Nursing Questions on Vital Signs PDF

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make them nursing questions nurrsing context: create 100 question related to the reading mulitple choice and select all applies and give explanations at the end for the reasonings of the answers: make it nurses questions specicfually nuringn school only, add nurisnf contect and have answes and explanarion: make it nurses questions specicfually nuringn school only, add nurisnf contect and have answes and explanarion CHAPTER 18 Measuring Vital Signs Learning Outcomes After completing this chapter, you should be able to: Describe the physiological processes involved in regulating body temperature, pulse, respirations, and blood pressure. Convert between the Fahrenheit and centigrade temperature scales. Discuss expected normal vital signs findings for various age-groups. Recognize patient vital signs readings that should be referred to the primary care provider. Define arterial oxygen saturation, hypoxia, hyperventilation, and hypoventilation. Define hypotension, hypertension, essential hypertension, and secondary hypertension. Select the correct site and equipment for measuring the temperature, pulse, respiration, and blood pressure of patients in various age-groups. Demonstrate correct technique and procedures for measuring temperature, pulse, respiration, and blood pressure. Explain the importance of several measurements to interpret a patient’s blood pressure. State at least one nursing diagnosis to describe a problem for each of the vital signs: temperature, pulse, respirations, and blood pressure. Describe nursing interventions for the patient (1) with temperature alterations, (2) with impaired respiratory status, (3) diagnosed with high blood pressure (hypertension), and (4) with alterations in pulse parameters. Identify important tips to teach your patients in managing their hypertension. Key Concepts Oxygenation (respirations) Perfusion (pulse, blood pressure) Thermoregulation Vital signs Related Concepts See the Concept Map at the end of this chapter. Example Client Conditions Hyperthermia/Heat Stroke Hypothermia Hypotension Hypertension Meet Your Patients Your instructor has scheduled a clinical day at a local community health fair for students to answer health-related questions, administer flu vaccines, check blood sugar levels, and take vital signs: temperature, pulse, respirations, and blood pressure (BP). You have been asked to check vital signs. Jason. The first person who arrives at the booth is Rosemary, a young mother, with Jason, her 2-year-old son. She tells you he has been eating poorly and is very irritable. The child’s skin is warm and dry, and he is flushed. Rosemary explains that she does not have a thermometer, and she would like you to take her son’s temperature. Jason’s axillary temperature is 38.8°C (101.8°F). Now it is time to think like a nurse. What could this temperature reading mean? What, if any, additional data should you collect? How will you explain your findings to Rosemary? What action would you advise Rosemary to take? You may not yet have all the theoretical knowledge you need to answer these questions, but try to do so anyway, based on your present knowledge base and your life experiences. Ms. Sharma. The next person to arrive at the booth is Ms. Sharma, an active 80-year-old woman who works part time in a local literacy program and walks 3 miles four times per week. Ms. Sharma notes that she has “lost a little pep. I don’t feel sick, but I’m tired lately.” Her pulse is difficult to feel. The rhythm is irregular, and the strength of the pulse is uneven—some beats are strong, while others are weak. What might this finding mean? What questions do you have for Ms. Sharma? What, if any, additional data should you collect? How will you explain your findings to Ms. Sharma? What action would you advise her to take? Mr. Jackson. As Mr. Jackson sits down next to you, you notice he is short of breath. His respiratory rate is 28 breaths/min, and he appears to be struggling to breathe. What do you think this respiratory rate means? What should be your next action? What would you say to Mr. Jackson? Lucas. The next patient to arrive is Lucas, a 35-year-old accountant who works for a firm in a nearby office building. Lucas tells you he has been under a lot of stress and is worried about his BP. You measure his BP as 150/98 mm Hg. Is this an acceptable BP? What does this reading mean? What should you discuss with Lucas? What advice should you offer? You will gain the theoretical knowledge you need to answer the preceding questions as you work through this chapter and learn more about vital signs. ABOUT THE KEY CONCEPTS The key concepts of thermoregulation, perfusion, and oxygenation pertain to specific vital signs you learn about in this chapter (temperature, pulse, respirations, and BP). A grasp of these underlying concepts will help you understand and remember the rationale for what you do when measuring and interpreting vital signs. WHAT ARE VITAL SIGNS? The concept of vital signs (VSs) suggests assessment of vital or critical physiological functions. Variations in temperature, pulse, respirations, or BP are indicators of a person’s state of health and function of the body systems. These four assessments are among the most frequent you will make as a nurse. Because of their importance, accurate measurements and documentation of each VS are a top priority. Do not become complacent when a patient’s VSs are within normal limits. Although stable VSs may indicate physiological well-being, they do not guarantee it. VSs alone are limited in detecting some important physiological changes. For example, VSs may sometimes remain stable even when there is a moderately large amount of blood loss. KEY POINT: Evaluate the VSs in the context of your overall assessment of the patient. Other Vital Signs Some experts have recommended adding other factors that affect patient care and outcomes to the four traditional measures of physiological status: Pain. This is viewed by many as the fifth VS (Baker, 2017; Rosenberg, 2018). See Chapter 28. Oxygen saturation. Pulse oximetry provides important information on arterial blood oxygen concentration. Smoking status is important to assess based on the impact of smoking on body functions and thus VSs. Emotional distress. This can have an impact on overall physiological functioning. Rather than being overly concerned about whether these parameters should be referred to as VSs, we recommend that nurses include them in all of their ongoing assessments of patients. iCare 18-1 Measuring Vital Signs Measuring vital signs seems pretty straightforward. How can you incorporate caring into this technical task? Simple Solution: Approach every patient unhurriedly. Introduce yourself, make eye contact, and explain what you will be doing before you touch the person. Ensure your voice is low, calm, and kind. “Hello, Mr. Smith. My name is Annie Gates. I’m a student nurse. I need to take your vital signs, which includes taking your blood pressure and measuring your temperature, pulse, and breathing rate. Is it okay with you that I perform these tasks?” Introducing yourself and explaining your actions shows respect for the person’s autonomy. In addition, you are informing and educating the patient about the plan of care and allowing them an opportunity to consent or refuse. A warm and kind voice convey caring. When Should I Measure a Patient’s Vital Signs? In the Meet Your Patients scenario, patients asked you to take their VSs. However, in many clinical settings, VSs are measured and documented in the following commonly occurring circumstances: On admission to the hospital For inpatients, at the beginning of a shift At a visit to the healthcare provider’s office or clinic Before, during, and after surgery or certain procedures To monitor the effects of certain medications or activities Whenever the patient’s condition changes The ideal frequency for assessing VSs depends on the patient’s condition and the events taking place (Academy of Medical-Surgical Nurses [AMSN], 2019; Ghosh et al., 2018). Agency policies also determine the frequency for monitoring and recording VSs. The following list contains commonly used frequencies: In the hospital: once every 4 to 8 hours In the home health setting: at each visit In the clinic: at each visit In skilled nursing facilities, also known as convalescent hospitals: weekly to monthly It is up to the nurse to decide whether VSs need to be monitored more frequently than prescribed by the primary care provider. You must always obtain an initial set of VSs to establish the patient’s baseline. When a patient’s VSs vary from their baseline, you should assess and document them more frequently to determine a trend in the degree and severity of the variation. As a beginning practitioner, you should validate your clinical assessments with a more experienced nurse and determine how often to reassess. KEY POINT: A baseline is important for evaluating a change in the patient’s physiological status. Such a change may be caused by a disease state, the effect of therapies, or changes in physical activity or environment. Table 18-1 shows average or normal findings for adults, but it is important to remember that each person has their own baselines for “normal.” If a patient’s VSs vary from established norms, compare the findings with that person’s baselines. Table 18-1 Vital Signs: Average Normal Findings for Adults Mean Adult Temperature Oral Rectal 36.7°C–37°C (98°F–98.6°F)* 37.2°C–37.6°C (99°F–99.6)* Pulse Normal range Average 60–100 beats/min 80 beats/min Respirations Normal range 12–20 breaths/min Blood Pressure Normal range Less than 120 mm Hg systolic and less than 80 mm Hg diastolic Elevated 120–129 mm Hg systolic and less than 80 mm Hg diastolic Hypertension Stage 1 130–139 mm Hg systolic or 80–89 mm Hg diastolic Hypertension Stage 2 140 mm Hg or higher systolic or 90 mm Hg or higher diastolic Hypertensive Crisis Greater than 180 mm Hg systolic and/or greater than 120 mm Hg diastolic *This is revised downward from the traditional norms to reflect more recent research, Charbek (2015); Geneva et al. (2019); Mackowiak et al. (1992); Sund-Levander et al. (2002); Whelton et al., 2018). The systematic review reported the following mean normal temperatures: Oral 36.3°C (97.3°F), Rectal 36.9°C (98.3°F). The traditional Wunderlich (1871) average normal temperature is 37.0°C (98.6°F) to 37.5°C (99.5°F), depending on the measurement site. How Do I Document Vital Signs? Most agencies have special flow sheets for documenting VSs. If the VSs are not within normal limits, you will also document them in the nurses’ notes, along with any associated symptoms (e.g., cyanosis [blue-gray skin] with abnormal respirations). Nurses are required to take appropriate actions based on their assessment findings; therefore, you must also document your interventions (e.g., elevating the head of the bed when the patient has shortness of breath) in the electronic health record (EHR). BODY TEMPERATURE Body temperature is the degree of heat maintained by the body. It is the difference between heat produced by the body and heat lost to the environment. TheoreticalKnowledge knowing why You must understand the concept of thermoregulation to assess and support regulation of body temperature at a professional level. You will learn the normal temperature range, how heat is produced by and lost from the body, and factors that influence body temperature. What Is Thermoregulation? Thermoregulation is the process of maintaining a stable internal body temperature. To keep the body temperature constant, the body must balance heat production and heat loss. This balance is controlled by the hypothalamus, located between the cerebral hemispheres of the brain. Similar to a thermostat, the hypothalamus recognizes and responds to even small changes in body temperature that are sent to it by sensory receptors in the skin. Core Temperature Core temperature is the temperature deep within the body, such as in the viscera and liver. The temperature of the hypothalamus identifies the core body temperature. The pulmonary artery catheter measures the temperature of the blood and is the most accurate indicator of core body temperature. It is not routinely used in clinical practice because it requires an invasive procedure. KEY POINT: Rectal measurements are used to represent core temperatures, whereas oral and axillary measurements reflect surface temperatures. An adult’s normal internal (core) temperature ranges from about 36.1°C to 38.2°C (97°F to 100.8°F). Core temperature is typically 0.6°C to 1.2°C (1°F to 2°F) higher than surface (skin) temperature. What Is a Normal Temperature? No single number can be considered “normal,” because body temperature varies among individuals as a result of differences in metabolism. Furthermore, each person’s temperature fluctuates with age, exercise, and environmental conditions. However, the body does function optimally within a narrow temperature range. “Average” Normal Temperature There is little definitive evidence about what, exactly, is a normal temperature. You may see different values in the many sources you read. We can at least conclude that the traditional belief of 37°C (98.6°F) for an average normal reading is too high, based on available research. Older research found a mean normal adult oral temperature of 36.3°C (97.3°F) (Sund-Levander et al., 2002). (See Table 18-1.) A more recent study found a mean body temperature of 36.6°C (97.9°F), with a range of 35.3°C to 37.7°C (95.5°F to 99.8°F). It also found that older adults have lower body temperatures and noted variations in temperature based on gender (Obermeyer et al., 2017). Body temperature can be evaluated based on individual norms and variability (Marui et al., 2017; Sund-Levander et al., 2004). Table 18-2 shows age-related variations for all VSs, including temperature. Slight Variations in Temperature Variations of temperature above or below normal, if temporary, usually are not significant. Greater variations indicate a disturbance of function in some system or region of the body (Fig. 18-1). However, the degree of temperature elevation does not always indicate the seriousness of the underlying disease or condition. For example, some acute, even fatal, infections may cause only a mild temperature elevation. KEY POINT: A continuous elevation, even if slight, is cause for concern and indicates a need for further evaluation. What Is the Response to Variations in Temperature? The neurological feedback mechanism in the hypothalamus senses internal temperature changes and initiates compensatory mechanisms to maintain a stable environment. Decreasing the Body Temperature When heat sensors in the hypothalamus are stimulated, they send out impulses to reduce the body temperature. This activates compensatory mechanisms, such as peripheral vasodilation, sweating, and inhibition of heat production. Vasodilation (increase in the diameter of the blood vessels) diverts core-warmed blood to the body surface, where heat can be transferred to the surrounding environment. Increasing the Body Temperature When sensors in the hypothalamus detect cold, they send out impulses to increase heat production and reduce heat loss. To produce heat, the body responds by shivering and releasing epinephrine, which increases metabolism. To reduce heat loss, the blood vessels constrict. Vasoconstriction (narrowing of the blood vessels) conserves heat by shunting blood away from the periphery (where heat is lost) to the core of the body, where the blood is warmed. Piloerection (hairs standing on end) also occurs, but it is not an important heat-conserving mechanism in humans. FIGURE 18–1 Ranges of normal and altered body temperatures. Table 18-2 Comparison of Normal Vital Signs for Various Ages* AGE TEMPERATURE AVERAGE °C (°F) PULSE RANGE (beats per min) RESPIRATIONS RANGE (breaths per min) BLOOD PRESSURE AVERAGE (mm Hg) Newborn 36.8 (98.2)** axillary 130 (80–180) 30–60 80/40 1–3 years 37.7 (99.9)** rectal 110 (80–150) 20–40 98/64 6–8 years 37.0 (98.6)** oral 95 (75–115) 20–25 102/56 10 years 37.0 (98.6)** oral 90 (70–100) 17–22 110/58 Teen 37.0 (98.6)** oral 80 (55–105) 15–20 110/70 Adult 36.7 (98) oral 80 (60–100) 12–20 Less than 120/80 Adult older than 70 years 35–36.0 (95–96.8) oral 80 (60–100) 12–20 120/80, up to 160/95 *Note: Pulse and respirations are shown as ranges, not averages. This means that you might see either the low or high extreme for a short period of time without alarm. Ranges and averages should be used as guides, not absolutes. Example 1: A normal newborn’s respiratory rate may be as much as 60 when crying, or 30 when at rest. Example 2: An older adult being treated for hypertension may regularly have a blood pressure reading of up to 160/95. Although this is not desirable or “normal,” it may be normal for that patient but should be managed by a provider. **We speculate that based on recent literature for adult temperatures, these may all be slightly high. Definitive literature to support changes was not available. To interpret vital signs, you must know the patient’s baseline and the activity at the time of the measurement. Behavioral Control of Temperature People also engage in behaviors to maintain a comfortable body temperature. In response to feeling cold, you turn up the thermostat, put on more clothing, or move to a warmer place. When you feel too warm, you turn on an air conditioner, remove some clothing, or take a cool shower. How Is Heat Produced in the Body? The body produces heat through the interaction of three factors: metabolism, the movement of skeletal muscles, and nonshivering thermogenesis. Metabolism Metabolism is the sum of all physical and chemical processes and changes that take place in the body. Metabolism uses energy and generates heat. The basal metabolic rate (BMR) is the amount of energy required to maintain the body at rest. Body size, lean muscle mass, and numerous hormones influence BMR, for example: Hyperthyroidism (an increase in the thyroid hormone, thyroxine) increases the BMR. Patients with hyperthyroidism often complain of feeling warm even when in a cool environment. Hypothyroidism (a decrease in the thyroid hormone, thyroxine) decreases the BMR, and less heat is produced. Your patient may complain of feeling cold in a warm environment. The hormones epinephrine and norepinephrine also increase BMR and heat production. Skeletal Muscle Movement Skeletal muscles are used in all body movements. Muscles need fuel to function. The breakdown (catabolism) of fats and carbohydrates in muscle produces energy and heat. While it requires very little muscle activity to sit and read this text, if you were to go for a run, you would use more skeletal muscles. After your run, your body temperature would be higher, perhaps as high as 38.3°C to 40°C (101°F to 104°F). In contrast, if you were to go outside without a coat when the temperature was 1.6°C (35°F), your hypothalamus would sense a drop in body temperature, and you would begin to shiver to produce heat. This mechanism is so efficient that body heat production can rise to about four times the normal rate in just a few minutes. Nonshivering Thermogenesis Nonshivering thermogenesis is the metabolism of brown fat to produce heat. It is used by infants because they cannot produce heat through shivering like adults and children. This mechanism disappears in the first few months after birth. How Is Heat Exchanged Between the Body and the Environment? Heat moves from an area of higher to an area of lower temperature; that is, cool air and objects “pick up” heat from warmer ones. The mechanisms that affect the exchange of heat between the body and the environment are radiation, convection, evaporation, and conduction (Fig. 18-2). Radiation is the loss of heat through electromagnetic waves emitting from surfaces that are warmer than the surrounding air. If the uncovered skin is warmer than the air, the body loses heat through the skin. This is why a cool room warms when it is filled with many people. In contrast, a person can acquire heat by turning on a heat lamp or being in the sunlight. Radiation accounts for almost 50% of body heat loss. Convection is the transfer of heat through currents of air or water. Nurses use this principle to intentionally effect changes in a patient’s body temperature, by immersion in a warm bath to raise body temperature for a hypothermic patient or use of a fan to reduce a fever in a hyperthermic patient. FIGURE 18–2 Mechanisms of heat exchange with the environment: radiation, convection, evaporation, and conduction. Evaporation occurs when water is converted to vapor and lost from the skin (as perspiration) or the mucous membranes (through the breath). Evaporation causes cooling. Water loss by evaporation is called insensible loss. Evaporation is affected by the moisture in the environment (humidity). In areas with high humidity, less moisture evaporates from the skin and less cooling occurs. Conduction is the process whereby heat is transferred from a warm to a cool surface by direct contact. You should not put patients on uncovered cool surfaces such as metal radiology tables or weighing scales. It could cause a drop in the patient’s temperature. Together, the processes of convection and conduction account for approximately 15% to 20% of all heat loss to the environment. What Factors Influence Body Temperature? The following are examples of internal and external factors involved in the delicate balance of body temperature: Developmental Level Infants and older adults are most susceptible to the effects of environmental temperature extremes. Infants lose approximately 30% of their body heat through the head, which is proportionally larger than the rest of the body compared with adults. This places them at increased risk for decreased body temperature. Body temperature begins to stabilize during early childhood and remains relatively stable until older adulthood. Older adults have difficulty maintaining body heat because of slower metabolism, decreased vasomotor control, and loss of subcutaneous tissue. Recent research supports that the average body temperatures of older adults age 60 years and older were lower (36.5°C ± 0.48°C; 97.7°F to 98.56°F) than adults younger than age 60 years (36.69°C ± 0.34°C; 98.04°F to 98.65°F) (Geneva et al., 2019). KEY POINT: You should ask your older patients their baseline temperature range. Some research findings have identified the average normal temperature for older adults as about 35°C to 36°C (95°F to 96.8°F). You should establish a baseline temperature and be alert for changes. Environment The environment strongly influences body temperature, for example: Warm room temperatures, high humidity, or hot baths can increase body temperature. Very high external temperatures can significantly increase internal temperatures, causing heat stroke. Cold environments, especially with strong air currents, can lower body temperatures and, in severe cases, lead to hypothermia. Gender A woman’s body temperature varies (as much as 0.6°C [1°F]) with her menstrual cycle and pregnancy. Body temperature is lower when progesterone levels are low and increases as progesterone levels increase. Hormonal fluctuations during menopause, when menses stop, often cause temperature fluctuations commonly known as hot flashes, which can produce episodes of intense body heat and sweating. Exercise The increase in metabolism from hard work or strenuous exercise can increase body core temperature to 38.3°C (101°F) or higher depending on environmental conditions. The sweat that is produced during exercise evaporates and helps to cool the body. Emotions and Stress Emotional stress, excitement, anxiety, and nervousness stimulate the sympathetic nervous system, causing production of epinephrine and norepinephrine. These trigger an increase in the metabolic rate, which in turn increases body temperature. Circadian Rhythm The body has an internal physiological 24-hour cycle called the circadian rhythm. Certain physiological processes (e.g., changes in temperature and BP) occur every 24 hours. Temperature can fluctuate 0.6°C to 1.2°C (1°F to 2°F) and is usually lowest in the early morning hours and highest in late afternoon or early evening. You need to take several readings at different times of the day. ThinkLike a Nurse 18-1: Clinical Judgment in Action You notice the following temperature readings in your patient’s EHR: 0400: 97.4°F 0800: 97.9°F 1200: 98.4°F 1600: 99.6°F 2000: 100.9°F When you assess the patient’s temperature at midnight, it is 38.4°C (101.2°F). What do you notice about the pattern of the temperature readings? What is important in this scenario? As a nursing student, what should you do? KnowledgeCheck 18-1 Which age-groups are most susceptible to thermoregulation problems and why? List five factors that affect body temperature. What are the compensatory mechanisms for decreasing body temperature? What are the compensatory mechanisms for increasing body temperature? What Is a Fever (Pyrexia)? Fever, or pyrexia, is an oral temperature higher than 37.8°C (100°F) or a rectal temperature of 38.3°C (101°F) in an adult. A person with a fever is said to be febrile; one without fever is afebrile. Baseline effects—Because older adults have a lower-than-average baseline, they may experience fever at a temperature lower than the traditional definition given earlier. A moderate fever is the body’s natural defense against infection (up to 39.5°C [103°F]), and although uncomfortable, it does not pose a threat to most patients. A fever is beneficial because it enhances the immune response. Specifically, it: 1. >Kills or inhibits the growth of many microorganisms 2. Enhances phagocytosis 3. Causes the breakdown of lysosomes and self-destruction of virally infected cells 4. Causes the release of interferon, a substance that protects cells from viral infection KEY POINT: Older adults may be unable to reach the fever temperature range necessary to develop a strong inflammatory response to infectious diseases (Geneva et al., 2019). KEY POINT: Hyperpyrexia, a fever above 41.0°C (105.8°F), is dangerous and requires intervention to prevent damage to body cells, especially in the brain, leading to confusion, delirium, seizures, or coma. In addition, vascular collapse may follow, producing cerebral edema, shock, and death. Death usually results if body temperature becomes higher than 43°C to 44°C (109°F to 112°F) (McCance & Huether, 2019). However, some patients who are sensitive to slight temperature elevations (e.g., those with epilepsy) may experience these detrimental effects at temperature lower than 41.0°C (105.8°F). What Causes a Fever? Fever occurs when in response to pyrogens (fever-producing substances), the body’s thermostat resets at a higher temperature. The following occur: Pyrogens—When bacteria or other foreign substances invade the body, they stimulate phagocytes (specialized white blood cells), which ingest the invaders and secrete pyrogens (e.g., interleukin-1). Hypothalamus and set point—Pyrogens induce secretion of prostaglandins (substances that reset the hypothalamic thermostat at a higher temperature). The reset value is called the set point. The body’s heat-regulating mechanisms then act to bring the core temperature up to this new setting. When the stressor is removed, the set point resets at normal. Fever Occurs in Three Phases The following are the three phases in which fever occurs: Initial phase (febrile episode or onset): The period during which body temperature is rising but has not yet reached the new set point. The onset of fever may be sudden or gradual, depending on the condition causing it. The person usually feels chilly and generally uncomfortable and may shiver. Second phase (course): The period during which body temperature reaches its maximum (set point) and remains fairly constant at the new higher level. The person is flushed and feels warm and dry during this phase, which may last from a few days to a few weeks. Third phase (defervescence or crisis): The period during which the temperature returns to normal. The person feels warm and appears flushed in response to vasodilation. Diaphoresis occurs, which assists with heat loss by evaporation. This phase is commonly referred to as the fever’s “breaking.” Four Ways to Describe a Fever Intermittent fever: Temperature alternates regularly between periods of fever and periods of normal or below-normal temperature without pharmacological intervention, or the temperature returns to normal at least once every 24 hours. Remittent fever: Fluctuations in temperature (greater than 2°C [3.6°F]), all above normal, during a 24-hour period. Constant (sustained) fever: Temperature may fluctuate slightly (less than 0.55°C [1°F]) but is always above normal. Relapsing (or recurrent) fever: Short periods of fever alternating with periods of normal temperatures, each lasting 1 to 2 days. Example Client Condition: Hyperthermia/Heat Stroke Hyperthermia, like hyperpyrexia (fever), is a body temperature above normal. KEY POINT: However, in hyperthermia, the elevated body temperature is higher than the set point. The hypothalamic regulation of body temperature is overwhelmed and does not reset the set point as it does in fever. Hyperthermia occurs because the body cannot promote heat loss fast enough to balance heat production or high environmental temperatures. Example Client Condition: Hypothermia Hypothermia is an abnormally low core temperature, usually less than 35°C (less than 95°F) (Peiris et al., 2018). However, you must know the person’s usual normal range of temperature because some people, especially older adults, have a normal temperature of less than 35°C (less than 95°F). See the accompanying Example Client Condition: Hypothermia. PracticalKnowledge knowing how Now that you understand the concept of thermoregulation, you are ready to gain the practical knowledge of how to assess and support a patient’s body temperature. ASSESSMENT NP In our daily routines, we commonly assess temperature by touch. For example, you can use simple touch to detect fever; however, you cannot differentiate degrees of fever. Because VSs are used as indicators of a patient’s health status, it is essential to have an accurate measure. To see the sequence of steps to take when measuring a patient’s temperature, refer to Procedure 18-1. Temperature Measurement Scales: Fahrenheit and Centigrade Two scales are used for recording temperature: Fahrenheit and centigrade (or Celsius), a metric scale. Most people in the United States are familiar with the Fahrenheit scale; however, some healthcare agencies use centigrade. Electronic and tympanic membrane thermometers can usually measure temperature in either scale; often all you need to do is to flip a switch. Some types of thermometers provide only one scale (Fig. 18-3 shows both scales), so you may need to convert a reading from one scale to the other. You may have a conversion app on your cell phone or find a conversion tool on the Internet. If you need to convert scales and do not have access to a conversion chart, you can use a mathematical formula. KEY POINT: To convert from Fahrenheit to centigrade, subtract 32 from the Fahrenheit temperature and multiply by 5/9. Example: A patient has a temperature of 102°F. What is the temperature measured in centigrade? (102 – 32) × 5/9 = (70 × 5) ÷ 9 = 39°C KEY POINT: To convert a centigrade reading to Fahrenheit, multiply the centigrade temperature by 9/5, and add 32. As a cross-check, we can verify the preceding example: Example: A patient has a temperature of 39°C: (39 × 9/5) + 32 = (351 ÷ 5) + 32 = 102.2°F What Equipment Do I Need? Nurses measure temperature with various kinds of thermometers. Each type has advantages and disadvantages (see Table 18-3), so you need to think critically about the type of thermometer best suited for each patient situation. Glass Thermometers Historically, the thermometer was a glass mercury-filled tube marked in degrees Fahrenheit or centigrade and read visually. Because of dangers associated with broken glass and exposure to mercury, healthcare facilities have complied with the U.S. Environmental Protection Agency (EPA) and the American Hospital Association (AHA) advice against use of equipment containing mercury (EPA, 2018). Electronic digital thermometers or glass or plastic thermometers containing other liquids, such as alcohol or gallium-indium-tin (galinstan), have replaced those containing mercury. Electronic Thermometers Electronic thermometers are rechargeable units consisting of an electronic probe attached to a portable unit by a thin wire. A beep sounds when the peak temperature is reached. The probe is covered with disposable plastic sheaths to prevent transmission of infection. You should discard the sheath after each use. KEY POINT: Most units have a red probe for rectal temperatures and a blue probe for oral. Use the correct probe for each site. Electronic Infrared Thermometers Electronic infrared thermometers are rechargeable units. They contain a sensor that detects heat in the form of infrared energy given off by the body. The thermometer does not touch the actual sites (e.g., tympanic membrane, temporal artery). A beep sounds when the peak temperature is reached. Disposable Chemical Thermometers Disposable chemical thermometers consist of a thin plastic strip, patch, or tape that contains a matrix of chemicals designed to produce color changes at a designated body temperature. Most are used once for an oral or axillary reading and then discarded. Disposable thermometers are useful in the home and for patients in protective isolation. When using this method, abnormal temperatures should be validated with a more reliable thermometer (Black, 2016). EXAMPLE CLIENT CONDITION: Hyperthermia/Heat Stroke FIGURE 18–3 Some thermometers are available with degree markings in Fahrenheit or centigrade. Left, Centigrade scale. Right, Fahrenheit scale. What Sites Should I Use? You must choose the safest, most accurate, and most reliable site for each patient. The sites for intermittent measurement are the mouth, rectum, axillae, tympanic membrane, and skin over the temporal artery. These sites allow the thermometer to contact body tissues that are well supplied with blood vessels, which is essential for accurate measurement. Each site has advantages and disadvantages, so you must choose the safest, most accurate, and most reliable site for each patient (Table 18-4). Sites for Core Temperature Sites in the pulmonary artery, esophagus, and bladder accurately measure core temperature. These sites are used in surgery and intensive care, but they are invasive, expensive, and impractical for most clinical settings. Measurements from these sites require the use of specially designed thermometers and practitioners with advanced training. KEY POINT: Pulmonary artery temperature is considered the gold standard with which other sites are compared. Temperature Variations at Different Sites Although research on site differences is conflicting, generally from lowest to highest readings, the sites are thought to be axillary, oral, tympanic membrane, rectal, and temporal artery. For axillary, oral, and rectal temperatures, there is an approximately 0.4°C (0.8°F) difference between each site and the next higher one. For convenience, nurses tend to round the fraction up to a full 0.5°C (1°F). For example, an axillary temperature of 36.7°C (98.06°F) is similar to an oral reading of 37.3°C (99.1°F) or a rectal reading of 37.8°C (100.0°F). Use this only to help you understand your patient’s data. You cannot reliably convert temperatures mathematically between sites. When you measure a temperature, record the value you obtain and the site used. ThinkLike a Nurse 18-2: Clinical Judgment in Action Convert the following temperatures and analyze the readings. What might they mean? 38.5°C ________ °F 96.5°F ________ °C 37.0°C ________ °F Rank the expected early evening temperatures of the following individuals from lowest to highest: A 22-year-old college athlete A 5-year-old kindergarten student An 88-year-old nursing home resident Table 18-3 Advantages and Disadvantages of Various Thermometers ADVANTAGES DISADVANTAGES Glass Thermometer Flexibility of use: Can be used for measuring oral, rectal, or axillary temperature Inexpensive initial cost Accuracy, as indicated by several studies Easily disinfected Do not use glass thermometers containing mercury. If you find one, recommend that it be replaced immediately. Easily broken: There is ongoing cost of replacement and risk for injury. Slow: It takes 3–8 min to obtain an accurate reading, depending on the site. Difficult for some people to read accurately. Electronic Thermometer Flexibility of use: Can be used for measuring oral, rectal, or axillary temperature Ease of use Rapid measurement: Takes 2–60 sec to obtain reading, depending on the unit Expensive initial cost. Requires regular inspection and maintenance to ensure accuracy. Data are conflicting regarding their accuracy compared to other types of thermometer. Need to be kept charged. Electronic With Infrared Sensor Ease of use Rapid measurement: Takes 2–5 sec to measure the temperature May be the most cost-effective method because of time and labor savings from their rapid reading capabilities Low rate of operator error Expensive initial cost. Less accurate than electronic or glass/plastic thermometers when used for tympanic membrane temperatures, as some studies indicate. Requires regular inspection and maintenance to ensure accuracy. Batteries require recharging. Disposable Chemical Thermometer Ease of use; requires no special training. Equally as accurate as the electronic thermometer. Less expensive than purchasing supplies for and maintaining an electronic thermometer. Because it is disposable, it may prevent spread of infection among patients. Recommended for measuring axillary temperature among pediatric patients over the age of 2 years (Black, 2016). Less accurate/reliable than glass or plastic thermometers. The skin must be dry. Indicates only body surface temperature; does not reflect core. Guidelines presently recommend only for pediatric patients. Table 18-4 Disadvantages and Contraindications of Various Sites for Measuring Temperature ADVANTAGES DISADVANTAGES CONTRAINDICATIONS Temporal Artery (passing the probe of an infrared thermometer over the front of the forehead to the temporal area) Most accurate representation of core temperature. Fast. Most scanners provide a reading in about 3 sec. No discomfort is associated with the procedure. Safe. Can be used even for those who cannot follow instructions (e.g., infants). Less prone to error than tympanic thermometer. Requires special scanning thermometer. Any covering, hat, hair, etc., prevents heat from dissipating and causes the reading to be falsely high. This is also true for the side of the head lying on a pillow. Wounds on or near the forehead; May be affected by diaphoresis (sweating), exercise, and environmental temperatures (Robertson & Hill, 2019). Rectal (inserting the thermometer into the rectal cavity) Accurately represents core (internal) body temperature. Seen as “gold standard” for routine measurement of body temperature (El-Radhi, 2014). Use for patients who are unable to follow directions for oral temperature monitoring or in situations in which accuracy is crucial. Most patients find this method objectionable or embarrassing. Not recommended as the first choice of site because of the risk for injury to the rectal mucosa, especially infants. Requires special positioning of the patient. Presence of stool may cause inaccurate reading and present a hygienic concern. May be frightening for young children and psychologically harmful to older children (El-Radhi, 2014). Patients who may be injured by the method (e.g., patients who have a rectal disease, severe diarrhea, or rectal surgery. Patients with cardiac surgery and some heart conditions because this method can stimulate the vagus nerve and slow the heart rate. Patients with hemorrhoids. Immunosuppressed patients or those with clotting disorders. Oral (thermometer placed under the tongue [sublingual]) Simple, convenient. Comfortable for most patients. Safe for adults and children who are old enough to follow simple directions. Glass thermometers can break if bitten. Slow; requires up to 8 min to ensure an accurate reading (if glass thermometer used). Patient must keep their mouth closed for several minutes (glass thermometers). Eating, drinking (e.g., ice water, hot tea), and smoking in the 30 minutes before measurement affect the accuracy of the reading. Bradypnea may create false temperature elevations. Tachypnea is associated with lowered readings because it increases evaporative cooling of the oral cavity. Patients who cannot cooperate with the instructions or who might be injured (e.g., infants and small children; patients who have had oral surgery, breathe through the mouth, have chills, or are confused or unconscious). Axillary (placed under the armpits) Safe Easy to use; accessible Can be used for children and for uncooperative or unconscious patients Recommended over rectal site for routine measurements Not reflective of core temperature. At the onset of fever, peripheral vasoconstriction is intense so the skin is cooler. Considered one of the least accurate sites. Diaphoresis (sweating) can cause the reading to be lower. Thermometer may need to be left in place for a long time (8 min if glass is used). Patients who are perspiring heavily. Does not accurately diagnose fever. If fever is suspected, confirm with measurement from another route. Tympanic Membrane (thermometer inserted into the ear canal) Fast (2–5 sec). Easy to use Can be used for children over age 6 months (Massaro & Schmitt, 2018) and for uncooperative or unconscious patients. Requires a special thermometer, a relatively expensive initial purchase. More variable than oral and rectal sites. Must be carefully positioned to ensure accuracy; prone to caregiver measurement errors. Presence of cerumen (earwax) may affect accuracy. Significant differences have been found between readings in left and right ear of same patient. Risk of injury to tympanic membrane if not positioned carefully to avoid touching it. May be uncomfortable for the patient. Research is mixed on the accuracy and reliability of tympanic membrane instruments. Hearing aids must be removed. Patients who have had recent ear surgery. Contraindicated in the presence of ear infection. Skin (disposable; placed against the skin, e.g., on the forehead) Safe, convenient. Easy to use for nonprofessionals. Can be used when other sites are contraindicated. Inexpensive (chemical paper or tape is used). Forehead skin temperature is generally 1°C–2°C (2°F–4°F) less than core temperature; if marked deviations in skin temperatures are detected, the readings must be confirmed via a more reliable route. Should not be used when accurate, reliable readings are required (e.g., in the presence of hypothermia or heatstroke). Skin temperatures may be accurate and reliable when obtained with an infrared skin thermometer (Wane et al., 2016). ThinkLike a Nurse 18-3: Clinical Judgment in Action Recall the patients in the Meet Your Patients scenario. Two-year-old Jason’s axillary temperature was 38.8°C (101.8°F), and his skin was warm, dry, and flushed. His mother told you that he had been eating poorly and was very irritable. What changes in behavior alert you that something is wrong? Do you have enough theoretical knowledge or patient information to know what is going on? What, if any, additional information about the patient situation do you need? PULSE The concept of perfusion refers to the continuous supply of oxygenated blood through the blood vessels to all body cells. The pulse is the rhythmic expansion of an artery produced when a bolus of oxygenated blood is forced into it by contraction of the heart. How do you think the pulse affects perfusion? How might perfusion affect the pulse? TheoreticalKnowledge knowing why To assess and support regulation of a patient’s pulse, you need to understand the concept of perfusion and know the normal pulse range, how the pulse is produced and regulated, and factors that influence pulse rate. An important reason to assess the pulse is to identify when more advanced monitoring is required. What Is a Normal Pulse Rate? Pulse rate is measured in beats per minute. The normal range for healthy young and middle-aged adults is 60 to 100 beats/min, with an average rate of 70 to 80 beats/min (see Table 18-1). When the heart rate is of concern, you will most likely use a cardiac monitor to determine not only the rate but also the rhythm and intensity of the pulse. How Does the Body Produce and Regulate the Pulse? The pulse wave begins when the left heart ventricle contracts and ends when it relaxes. Each contraction forces blood into the already filled aorta, increasing pressure within the arterial system. The intermittent pressure and expansion of the arteries cause the blood to move along in a wave-like motion toward the capillaries. You can palpate a light tap at the peak of the wave, when the artery expands. The trough (low point) of a pulse wave occurs when the artery contracts to push the blood along its way. The peak of the wave corresponds to systole, or the contraction of the heart. The trough corresponds to diastole, or the resting phase of the heart. Stroke volume is the quantity of blood forced out by each contraction of the left ventricle. You will not usually know your patient’s actual stroke volume, though it averages 70 mL in most healthy adults. If stroke volume decreases (as in a large blood loss, or hemorrhage), the body tries to maintain the same cardiac output by increasing the pulse rate. Cardiac output is the total quantity of blood pumped per minute. It is expressed in liters per minute and calculated as follows: Cardiac output = Stroke volume × Pulse (heart) rate For a person with a pulse of 80 beats/min and an average stroke volume (70 mL), the cardiac output would be about 5,600 mL (or 5.6 L) per minute. The autonomic nervous system (ANS) regulates the heart rate. Sympathetic stimulation increases the heart rate (and thus the cardiac output), whereas parasympathetic stimulation decreases it. For more information on the ANS, see Chapter 34. What Factors Influence the Pulse Rate? In a healthy adult, the peripheral pulse rate is the same as the heart rate. Therefore, taking the pulse is a quick and simple way to assess the condition of the heart, blood vessels, and circulation. The pulse varies in response to: Changes in the volume of blood pumped through the heart. Variations in heart rate. Changes in the elasticity of the arterial walls. Any condition that interferes with heart function. Impaired functioning of the nervous system. The heart and blood vessels are regulated by the nervous system, so conditions that interfere with normal functioning of the nervous system also affect the pulse. Other factors that may cause variations in pulse rate, rhythm, or quality include the following: Developmental level. Newborns have a rapid pulse rate. The rate stabilizes in childhood and gradually slows through old age. The resting heart rate may not significantly change with age; however, variability changes. It may take longer for the pulse rate to increase with stress and exercise and also to decrease afterward (Medline Plus, 2020). Thus, you should not rely solely on changes in the pulse rate of older adults to detect their response to external stressors. Gender. Adult women have a slightly higher pulse rate than do adult men. Exercise. Muscle activity normally increases the pulse rate. After exercise, a well-conditioned heart returns to a normal rate more quickly. People who are well conditioned have lower heart rates, both before and during exercise, than those who are less conditioned. Food intake. Ingestion of a meal causes a slight increase in pulse rate for several hours. Stress. Stress triggers the fight-or-flight sympathetic nervous system response, which increases both pulse rate and strength of the heart contractions (stroke volume). Fever. The pulse rate tends to increase about 10 beats/min for each degree Fahrenheit of temperature elevation. The reasons are that (1) the metabolic rate increases, and (2) in response to the fever, peripheral vasodilation occurs, causing a decrease in BP. The body then causes the heart to beat faster to compensate for the decreased BP. Disease. Diseases, such as heart disease, hyperthyroidism, respiratory diseases, and infections, are generally associated with increased pulse rates. Hypothyroidism is associated with decreased pulse rates. Blood loss. A small blood loss is generally well tolerated and produces only a temporary increase in pulse rate. Theoretically, a large blood loss stimulates the sympathetic nervous system, bringing about an increase in pulse rate to compensate for the decreased blood volume. However, research suggests that VSs are limited in their ability to detect large blood losses; thus, a stable pulse and BP are unreliable measures of the amount of loss. Position changes. Standing and sitting positions generally cause a temporary increase in pulse rate as a result of blood pooling in the veins of the feet and legs. This causes decreased blood return to the heart, decreasing BP, and subsequently increasing heart rate. Medications. Stimulant drugs (e.g., epinephrine) increase pulse rate. Cardiotonics (e.g., digitalis) and opioids (e.g., narcotic analgesics) or sedative drugs decrease pulse rate. Toward Evidence-Based Practice Geneva, I., Cuzzo, B., Fazili, T., & Javaid, W. (2019). Normal body temperature: A systematic review. Open Forum Infections Diseases, 6(4), ofz032. https://doi.org/10.1093/ofid/ofz032 Evidence-based practice from research evolves over time. In the largest meta-analysis to date, the researchers’ findings questioned the normothermia baseline axillary temperature range of 37.0°C to 38°C (98.6°F to 100.4°F) established by Wunderlich in 1868 and the current published overall mean body temperature of 36.8°C (98.2°F). Their analysis established a lower overall mean of 36.59°C (97.86°F). Further, per measure site, the average temperatures were calculated as 35.97°C (96.75°F) (axillary); 36.57°C (97.8°F) (oral); 36.61°C (97.9°F) (urine); 36.64°C (97.95°F) (tympanic); and 37.04°C (98.67°F) (rectal). Researchers attributed the differences between rectal and urine temperatures, both core body temperatures, as the noninvasive processes used in previous research to measure urine temperatures. The findings supported the lower body temperature in healthy older adults but found gender differences in body temperature were not clinically significant. The researchers concluded that body temperature is influenced by several variables, most importantly the patient’s age and site of measurement. Takayama, A., Takeshima, T., Nakashima, Y., Yoshidomi, T., Nagamine, T., & Kotani, K. (2019). A comparison of methods to count breathing frequency. Respiratory Care, 64(5), 555–563. Changes in or abnormal respiratory rates are one of the first indicators of deterioration in patients’ clinical conditions. Numerous researchers have found that it is the highest neglected vital sign by healthcare providers. In addition, numerous methods are used to assess respirations. Researchers examine the reliability of two quick assessment methods: (1) 15-s quadruple—count for 15 seconds and multiply by 4, and (2) breathing time—count the time needed for a single breath and divide by 60, with the standard method 1-minute breath count—counting respirations for 1 full minute (60 seconds). Results revealed that the 15-s quadruple method overestimated breathing frequency. The breathing time method (the duration between the beginning of inspiration and the beginning of the next inspiration) had better agreement with the 1-minute breath count. 1. How can research findings impact clinical practice? 2. What are important considerations when evaluating a patient’s temperature? 3. Why do you think the breathing time measurement method would more closely align with the 1-minute breath count? PracticalKnowledge knowing how Now that you understand some of the concepts and factors that produce the pulse, you are ready to learn the practical knowledge to assess and support this aspect of physical functioning. ASSESSMENT NP Assess the pulse by palpation (feeling) or auscultation (listening with a stethoscope). To palpate the pulse, select the pulse site and lightly compress the patient’s artery against the underlying bone with your index and middle fingers. When a patient’s pulse is difficult to palpate, you may need to use a Doppler device, which has an ultrasound transducer that transmits the pulse sounds to an audio unit. For a summary of the steps for assessing a patient’s peripheral pulse, see Procedure 18-2. What Equipment Do I Need? To count the pulse, you need a watch or clock with a second hand or digital display. To auscultate the pulse, you will use a stethoscope. The stethoscope does not magnify sounds but rather blocks out noise so that you can hear the heartbeat and other faint sounds. A stethoscope consists of a sound-transmitting device (bell and diaphragm) attached to earpieces by rubber tubing and hollow metal tubes (Fig. 18-4): Bell—Use to hear low-frequency sounds (e.g., certain heart sounds) Diaphragm—Use to assess high-frequency sounds (e.g., lung sounds) Stethoscopes can be either single lumen or double lumen. A single-lumen stethoscope has one tube connected to the chest piece. A double-lumen stethoscope has two tubes attached to the chest piece. Double-lumen stethoscopes are more sensitive than single-lumen instruments. Most stethoscopes come with soft earpieces that help seal your ear canal to block room noise from interfering with the sound. Stethoscopes have varying lengths of tubing. Short tubing requires you to be close to the patient and to bend more, but the sound may be a bit better than with longer tubing, which is more likely to rub against the body or clothing. Some stethoscopes are made to work effectively through clothing. Unless you have that type, place the instrument directly on the skin. Digital stethoscopes are also available to provide sound clarity in noisy environments, for patients who are obese, and for care providers who have a hearing impairment. To prevent injury, do not wear a stethoscope around your neck. To prevent cross-contamination, always clean your stethoscope before and after using it to examine a patient. Use a 70% isopropyl alcohol, sodium hypochlorite, or benzalkonium chloride wipe. Alcohol pads are highly recommended because in addition to cleaning, they do not damage the rubber components (Rao et al., 2017). To inhibit recontamination of stethoscope membranes, some researchers also recommend using chlorhexidine (Alvarez et al., 2016). FIGURE 18–4 (A) A stethoscope. (B) The bell, for low-frequency sounds. (C) The diaphragm, for high-frequency sounds. What Sites Should I Use? Nurses assess the pulse at the apex of the heart (apical pulse) or at a place where an artery can be pressed by the fingers against a bone (peripheral pulses). Peripheral sites are shown in Figure 18-5. The choice of pulse site depends on the reason for assessing the pulse and/or the accessibility of a site. You would, for example, use the: Radial artery for routine assessment of VSs. This is the most commonly used site because it is easily found and readily accessible. Brachial artery when performing cardiopulmonary resuscitation (CPR) of infants. Carotid artery during CPR of adults and for assessing circulation to the brain. Temporal artery when assessing circulation to the head or when other sites are not easily accessible. Dorsalis pedis (also called pedal pulse) and posterior tibial arteries for assessing peripheral circulation to the feet and legs. Femoral artery to determine circulation to the legs and for children. Popliteal artery for assessing circulation to the lower leg. FIGURE 18–5 Sites commonly used for assessing a pulse. ThinkLike a Nurse 18-4: Clinical Judgment in Action If you obtain a very slow radial pulse, how might you check to be sure your count is accurate? What kind of nursing knowledge does this require (i.e., theoretical, practical, self, or ethical)? When Should I Take an Apical Pulse? KEY POINT: The apical pulse reading is the most accurate of the pulses. In a healthy person, the apical and peripheral pulses should be about the same rate. However, in some cardiovascular diseases, they can differ. If the heartbeat is weak, for example, some beats may be too weak to feel in a peripheral site. In this case, you would obtain a lower count for the radial than for the apical pulse. Use the apical site when: The radial pulse is weak or irregular. The rate is less than 60 beats/min or greater than 100 beats/min. The patient is taking cardiac medications (e.g., digitalis). The patient is an infant or is a child up to age 3 years (because peripheral pulses may be difficult to palpate). For children, the location is different, depending on age (Fig. 18-6). For a summary of steps for assessing an apical pulse, see Procedure 18-3. When Should I Take an Apical-Radial Pulse? You will sometimes need to obtain radial and apical pulse readings at the same time to assess for heart function or the presence of heart irregularities. A difference between the two counts (pulse deficit) indicates that not all apex beats are being transmitted or felt at the radial artery. As you are listening at the apical site, you will hear a beat without feeling a pulse at the radial artery. You may detect a pulse deficit in conditions that interfere with peripheral perfusion, such as atrial fibrillation. You should promptly report pulse deficits to the primary care provider. See Procedure 18-4 for step-by-step instructions. FIGURE 18–6 Location of apical pulse for adults and children. KnowledgeCheck 18-2 For each of the following, would you expect the pulse rate to be greater or less than the normal adult rate of 80 beats/min? A healthy, professional tennis player A newborn infant An adolescent who has just finished running track A patient who has just undergone a painful procedure A patient with a fever An accident victim who is hemorrhaging A 90-year-old man What Data Should I Collect? You will need data about three characteristics of the patient’s pulse: rate, rhythm, and quality. Pulse Rate To assess the pulse rate, count the number of beats per minute while palpating or auscultating. Begin the count with a beat that is counted as zero (Centers for Disease Control and Prevention [CDC], 2019a); however, due to discrepancies in the literature, follow your agency’s policy. For normal, healthy adults, you can determine the rate of a regular heart rhythm by counting the pulse for 15 seconds and multiplying the result by 4 or 30 seconds, and then multiply by 2. If the pulse is irregular or slow, always count for 1 full minute. Table 18-1 identifies average pulse rates for adults, while Table 18-2 provides pulse rates for other age groups. Bradycardia (brady = slow, cardia = heart)—Rates below 60 beats/min Tachycardia (tachy = rapid, cardia = heart)—Rates over 100 beats/min Pulse Rhythm The intervals between heartbeats establish a pattern known as the rhythm. Normally, the heart beats at regular intervals, much like a metronome. When the intervals between beats vary enough to be noticeable, the rhythm is abnormal (dysrhythmia). Abnormal rhythms may be (1) single beats that occur too early or too late, or (2) a group of irregular beats that form a pattern. When assessing an irregular pulse, it is important to determine whether the beat is regularly irregular (an irregular rhythm that forms a pattern) or irregularly irregular (an unpredictable rhythm). To make this distinction, you must count the rate for a full minute. An irregular heart rhythm can be very serious and may require additional assessment by electrocardiogram (ECG), a procedure that traces the electrical pattern of the heart. Pulse Quality The quality of the pulse is assessed by determining the pulse volume and bilateral (both sides) equality of pulses. Pulse Volume Pulse volume refers to the amount of force produced by the blood pulsing through the arteries. Normally, the pulse volume for each beat is the same. The following terminology refers to the characteristics of the pulse volume; the numbers are assigned on a scale of 0 to 3. 0—Absent: Pulse cannot be felt. 1—Weak or thready: Pulse is barely felt and can be easily obliterated by pressing with the fingers. 2—Normal quality: Pulse is easily palpated, not weak or bounding. 3—Bounding or full: Pulse is easily felt with little pressure; not easily obliterated. Bilateral Equality Bilateral equality is useful in determining whether the blood flow to a body part is adequate. Assess bilateral equality by comparing the pulses on both sides of the body for equal volume. For example, if you are concerned about the circulation to the left hand, assess both the right and left radial arteries to determine whether the volume is the same. If the pulses feel the same, they are said to be equal in strength bilaterally. If one pulse is stronger than the other, then the pulses are unequal bilaterally. You would record, “Radial pulses unequal in strength bilaterally; weaker in left arm.” You may also document the equality by using a pulse volume scale. For example, you might record, “Radial pulses unequal in strength bilaterally; Right 2, Left 1.” Absent or Weak Pulse If a peripheral pulse is absent or weak, it may be because the circulation is compromised in that extremity. Assess for pallor or cyanosis to confirm this. Cyanosis is a bluish or grayish discoloration of the skin resulting from deficient oxygen in the blood. Pallor refers to the paleness of skin in one area when compared with another part of the body. For example, when circulation to the lower extremities is compromised, the feet often appear pale in comparison with the trunk or arms, and the feet may feel cool to the touch. In addition, the dorsalis pedis and/or posterior tibial pulses may be weak or absent. ANALYSIS/NURSING DIAGNOSIS NP Pulse changes are symptoms, not problems. Therefore, nursing diagnoses are useful for describing the condition that is causing the pulse changes. Ineffective Tissue Perfusion (Peripheral) can be used when a pulse is absent or weak and cool, pale skin is present (Saba, 2017). Risk for Impaired Skin Integrity and Risk for Impaired Tissue Integrity may be used as secondary diagnoses when Ineffective Tissue Perfusion is present. If tissue is not adequately perfused, tissue ischemia and necrosis (death of tissue) may occur. Deficient Fluid Volume may cause the pulse to be weak and thready. Excess Fluid Volume may cause the pulse to be bounding and full. Decreased Cardiac Output may cause tachycardia, bradycardia, or changes in pulse volume. NOTE: By itself, a change in pulse (e.g., weak and thready) is not adequate to support the preceding diagnoses. Other symptoms must also be present (e.g., fatigue, delayed capillary refill). PLANNING OUTCOMES/EVALUATION NP NOC standardized outcomes include the following: Vital Signs Status is the only outcome that directly pertains to assessing the pulse. Other outcomes depend on the nursing diagnosis causing the pulse changes. For example, Ineffective Peripheral Tissue Perfusion can be monitored with the NOC label of Circulation Status. Some individualized goal/outcome statements you might write for pulse status follow: Apical pulse 60 to 80 beats/min when at rest. Pedal pulses 80 to 100 beats/min, 2 (on a scale of 0 to 3), and equal bilaterally. ThinkLike a Nurse 18-5: Clinical Judgment in Action Did you notice that the pulse rates in the preceding two goals are not the same as the full normal range shown in Table 18-1? What do you think might be a reason for this? PLANNING INTERVENTIONS/IMPLEMENTATION NP NIC standardized interventions include the following examples: Dysrhythmia Management, which applies to monitoring an abnormal pulse Vital Signs Monitoring, which may be used for general evaluation of patients who do not have an identified problem with the pulse. Specific nursing activities and focused assessments for a patient with a dysrhythmia depend on the cause of the problem and on specific prescriptions from the provider. For example, a patient with a pulse rate of 50 beats/min is usually considered to have bradycardia. However, such a slow resting heart rate would be perfectly normal for a well-trained athlete. Some dysrhythmias are benign; that is, they are not dangerous to the patient and require no interventions. Nursing strategies that address dysrhythmias, regardless of cause, include the following: Closely monitor the patient’s VSs. A reduced heart rate may alter BP and tissue perfusion. The extent of intervention depends on the effect of the dysrhythmia on the patient’s other VSs. Monitor the patient’s activity tolerance. Degree of activity, orientation, and level of fatigue while the dysrhythmia is present are indicators of the patient’s ability to tolerate the dysrhythmia. Monitor VSs before, during, and after activity. Collect and assess laboratory data as prescribed. Cardiac function depends on normal electrolyte balance, particularly potassium, calcium, and magnesium levels. If a patient is receiving medications that affect cardiac rhythm, serum levels of these medications must be checked periodically. Help determine the cause of the dysrhythmia. Determine when the patient experiences the dysrhythmia. Are there precipitating or alleviating factors? Administer antidysrhythmic medications. These are prescribed to control the heart rhythm. iCare Provide emotional support. The patient experiencing a dysrhythmia may be frightened by the experience. Explain all procedures to the patient and maintain a calm presence. Family members may also be frightened. Be sure to include them in your explanations and teaching. ThinkLike a Nurse 18-6: Clinical Judgment in Action Which of the following findings should be referred to the primary healthcare provider so that an electrocardiogram (ECG) can be prescribed? Why? Patient A, who has a radial pulse of 100 beats/min, regular, and equal bilaterally Patient B, who has a regular apical pulse of 100 beats/min Patient C, who has a very irregular apical pulse of 78 beats/min Recall the patients in the Meet Your Patients scenario. Ms. Sharma is an active 80-year-old woman who works part time and exercises four times per week. She is complaining of feeling tired. You find that her pulse is irregular and uneven. What other patient data do you need to know? How would you go about getting this additional information? What actions should you consider taking while meeting with Ms. Sharma? What theoretical knowledge (rationale) supports your beliefs and actions? RESPIRATION Respiration is the exchange of oxygen and carbon dioxide in the body. The process of respiration has two aspects: mechanical and chemical. Mechanical. The mechanical aspects of respirations involve the active movement of air into and out of the respiratory system. This is known as pulmonary ventilation or, more commonly, breathing. Chemical. The chemical aspects of respiration include the following: External respiration—The exchange of oxygen and carbon dioxide between the alveoli and the pulmonary blood supply Gas transport—The transport of these gases throughout the body Internal respiration—The exchange of these gases between the capillaries and body tissue cells This chapter focuses on the mechanical aspects of respiration. Chapters 33 and 34 explore gas exchange and transport throughout the body. TheoreticalKnowledge knowing why To assess and support patients’ respirations, you will need to know the normal range of respiratory rates, how respiration is regulated, the mechanics of breathing, and factors that affect respiration. What Is a Normal Respiratory Rate? Respiratory rate normally varies with age, exertion, emotions, and other factors. Normal adult respirations are identified in Table 18-1 and normal respiratory rates at other developmental stages in Table 18-2. How Does the Body Regulate Respiration? Special respiratory centers in the medulla oblongata and pons of the brain, along with nerve fibers of the autonomic nervous system, regulate breathing in response to minute changes in the concentrations of oxygen (O2) and carbon dioxide (CO2) in the arterial blood. KEY POINT: The primary stimulus for breathing is the level of CO2 tension in the blood. Central chemoreceptors, located in the respiratory centers, are sensitive to CO2 and hydrogen ion (pH) concentrations. Minor increases in either stimulate respirations. Peripheral chemoreceptors are located in the carotid and aortic bodies. The partial pressure of oxygen in arterial blood (PaO2) is normally between 80 and 100. When the PaO2 falls below normal, peripheral chemoreceptors stimulate respirations. Usually breathing is an involuntary action that requires little effort. However, it is possible to exert conscious control over respiration (e.g., a young child holding their breath during a temper tantrum; a person holding their breath when swimming). What Are the Mechanics of Breathing? Pulmonary ventilation depends on changes in the capacity of the chest cavity (Fig. 18-7). Inspiration In response to impulses sent from the respiratory center along the phrenic nerve, the thoracic muscles and the diaphragm contract. The ribs move upward from midline ½ to 1 inch (1.2 to 2.5 cm), the diaphragm moves downward and out about 0.4 inch (1 cm), and the abdominal organs move downward and forward, expanding the thorax in all directions. As expansion causes airway pressure to decrease below atmospheric pressure, air moves into and expands the lungs. This stage of respiration (drawing air into the lungs) is termed inspiration. Expiration When the diaphragm and thoracic muscles relax, the chest cavity decreases in size, and the lungs recoil, forcing air from the lungs until the pressure within the lungs again reaches atmospheric pressure. This stage, which involves the expulsion of air from the lungs, is called expiration. Expiration is passive and normally takes 2 to 3 seconds, compared with 1 to 1.5 seconds for inspiration. During normal breathing, the chest wall and abdomen gently rise and fall. FIGURE 18–7 Changes in thoracic cavity during inspiration and expiration. (A) During inspiration. (B) During expiration. KnowledgeCheck 18-3 Which two gases are exchanged through respiration? Which respiratory process involves the movement of air into and out of the lungs? What is external respiration? What is the primary stimulus for breathing? What mechanical forces allow the lungs to expand? What Factors Influence Respiration? KEY POINT: Changes in respiratory rate–altered breathing frequency is an early indication of clinical deterioration in patients. Therefore, you must conduct further assessments to formulate hypotheses about contributing factors. To interpret the meaning of your patients’ respiratory data, you need to be aware of factors that influence breathing. Developmental level. A newborn’s respiratory rate usually ranges from 40 to 60 breaths/min. However, some references give an upper limit of 90 breaths/min so long as it is for a short period of time (transient tachypnea). The rate gradually decreases until it reaches the normal adult rate of 12 to 20 breaths per minute. The respiratory rate decreases slightly in older adults. Respirations, often thought of as the forgotten VS (Loughlin et al., 2018), provide essential information on your patient. In older adults, respiratory rates greater than 28 beats/min are considered tachypneic in older adults (Charilaos & Bhardwaj, 2019). You should conduct a more thorough assessment of older adults to identify other cues of adverse events. Exercise. Muscular activity causes a temporary increase in respiratory rate and depth to increase oxygen availability to the tissues and to rid the body of excess carbon dioxide. Pain. Acute pain causes an increase in respiratory rate but a decrease in depth. Stress. Psychological stress, such as anxiety or fear, may markedly influence respiration as a result of sympathetic stimulation. The most common change is an increase in rate. Smoking. Chronic smoking increases resting respiratory rate as a result of changes in airway compliance (elasticity). Fever. When heart rate increases because of fever, respiratory rate also increases. For every 0.6°C (1°F) the temperature rises, the respiratory rate may increase up to 4 breaths/min. Hemoglobin. Respiratory rate and depth increase as a result of anemia (reduced hemoglobin), sickle cell anemia (abnormally shaped red blood cells), and high altitudes. When hemoglobin is decreased or abnormal, the rate and depth of respirations, as well as the heart rate, may increase to maintain adequate tissue oxygenation. High altitudes inhibit the binding of oxygen to hemoglobin and trigger similar compensation efforts. Disease. The rate of breathing may be increased or decreased by various diseases. For example, brainstem injuries and increased intracranial pressure may interfere with the respiratory center, inhibiting respirations or altering respiratory rhythm. Medications. Central nervous system depressants, such as morphine or general anesthetics, cause slower, deeper respirations. Caffeine and atropine can cause shallow, fast breathing. Position. Standing up maximizes respiratory depth; lying flat reduces respiratory depth. Slumping (sitting with shoulders forward and the back curved in a C shape) prevents chest expansion, which impedes breathing. ThinkLike a Nurse 18-7: Clinical Judgment in Action Consider the following patient situations. What effect would they have on respirations? A patient with four fractured ribs A woman who is 9 months pregnant A young child excited at their birthday party An adult who has consumed alcoholic beverages PracticalKnowledge knowing how Although you may assess the adequacy of external and internal respiration in various ways, it is pulmonary ventilation (breathing) that you assess as a VS. Accurate assessment of respirations depends on your ability to recognize normal breathing, abnormal breathing, and factors that affect breathing. This chapter discusses only assessment of respirations and analysis/diagnosis. For outcomes and interventions for respiratory problems, see Chapter 33. ASSESSMENT NP Because people can control their breathing rate, it is best to count respirations when the patient is unaware of what you are doing. One way to do this is to palpate and count the radial pulse, and then count the respirations before removing your fingers from the patient’s wrist. For the entire sequence of steps, see Procedure 18-5. What Equipment Do I Need? For measuring respiratory rate—a watch with a second hand or digital display For auscultating respirations—a stethoscope Many electronic thermometers have counter displays and signals that indicate 15-, 30-, and 60-second time intervals for counting respirations. What Data Should I Obtain? In addition to measuring the respiratory rate, you will observe indicators of overall respiratory function, including depth, rhythm, and effort, among others. For additional information on respiratory assessment, see Chapter 19 and Procedure 19-12. Respiratory Rate The respiratory rate is the number of times a person breathes (or completes a cycle of inhalation and exhalation) within 1 full minute. You can easily count and observe respirations by: Placing your hand on the patient’s chest (palpation) or observing (inspection) the number of times the patient’s chest or abdomen rises (inspiration) and falls (expiration) Placing your stethoscope on the patient’s chest (auscultation) and counting the number of inhalation and exhalation cycles KEY POINT: For a new patient or when you need to ensure accuracy, you must count for 60 seconds (Wheatley, 2018a). In some situations, agency policy may allow you to count for only 30 seconds and multiply by 2. If respirations vary from normal or you notice changes in the rate or depth, you should count for 1 minute by auscultation. Normal adult respirations are identified in Table 18-1 and for other developmental stages in Table 18-2. A person can tolerate apnea, cessation of breathing, for only a few minutes. If apnea continues for more than 4 to 6 minutes, brain damage and even death can occur. See Table 18-5 for terminology to describe respiratory rhythms. KEY POINT: Respiratory rate is a measure of the patient’s general condition, but rate alone is not a good indicator of the adequacy of respiration. You must also assess other characteristics of the respirations. Respiratory Depth Tidal volume is the amount of air taken in on inspiration—about 300 to 500 mL for a healthy adult. Specialized equipment is required to measure tidal volume. However, you can estimate the adequacy of tidal volume by observing the depth of a patient’s respirations. This is a subjective evaluation of how much or how little the chest or abdomen rises during breathing. Respiratory depth is described as: Deep—Taking in a very large volume of air and fully expanding one’s chest or abdomen Shallow—When the chest barely rises and is difficult to observe Normal—Falling between shallow and deep Respiratory Rhythm Rhythm is assessed simply as regular or irregular. Generally, the period between each respiratory cycle is the same, and there is a regular breathing pattern (see Eupnea in Table 18-5). Infant breathing rhythms are more likely to be irregular than adult rhythms. An abnormal breathing pattern may indicate other healthcare problems and deserves further assessment. Two abnormal breathing patterns, Cheyne-Stokes and Biot’s breathing, are discussed in Chapter 33. Respiratory Effort Respiratory effort refers to the degree of work required to breathe. Normal breathing is effortless. When diseases such as asthma or pneumonia are present, the person must work harder to breathe. Dyspnea is increased effort with breathing or labored breathing. Orthopnea is difficulty or inability to breathe when in a horizontal position. You will observe this in some patients with respiratory or cardiac conditions. iCare Breathing difficulties are uncomfortable for the patient and frequently produce fear, anxiety, and fatigue. Remain with the patient, initiate actions to improve breathing (e.g., positioning, respiratory treatment), and speak to the patient in a low, calming voice. Breath Sounds You will use a stethoscope to listen for breath sounds. Normal respirations are quiet. Abnormal (adventitious) sounds include the following: Wheezes are high-pitched, continuous musical sounds, usually heard on expiration. They are caused by narrowing of the airways. Wheezes can often be heard without a stethoscope. Rhonchi are low-pitched, continuous gurgling sounds caused by secretions in the large airways. They often clear with coughing. Crackles are caused by fluid in the alveoli. They are discontinuous sounds usually heard on inspiration, but they may be heard throughout the respiratory cycle. They may be high-pitched, popping sounds or low-pitched, bubbling sounds, and they have been described as being similar to the sound made by rubbing strands of hair together with the fingertips. Table 18-5 Respiratory Rates and Rhythm TYPE DESCRIPTION ILLUSTRATION Eupnea Normal respirations, with equal rate and depth, 12–20 breaths/min Bradypnea Slow respirations, less than 10 breaths/min Tachypnea Fast respirations, greater than 24 breaths/min, usually shallow Kussmaul respirations Respirations that are regular but abnormally deep and increased in rate Biot respirations Irregular respirations of variable depth (usually shallow), alternating with periods of apnea (absence of breathing) Cheyne-Stokes respirations Gradual increase in depth of respirations, followed by gradual decrease and then a period of apnea Apnea Absence of breathing Stridor is a piercing, high-pitched sound that is heard without a stethoscope, primarily during inspiration in infants who are experiencing respiratory distress or in someone with an obstructed airway. Stertor refers to labored breathing that produces a snoring sound. It is common with mouth breathing due to nasal congestion. The “death rattle” is a type of stertorous breathing. See Chapter 19 for further discussion of abnormal breath sounds. Chest and Abdomen Movement The chest or abdomen normally rises with inspiration and falls with expiration in a gentle and rhythmic pattern. When a person is having difficulty moving air into or out of the lungs, respiratory patterns change. Intercostal retraction refers to the visible sinking of tissues around and between the ribs that occurs when the person must use additional effort to breathe. Substernal retraction exists when tissues are drawn in beneath the sternum (breastbone). Suprasternal retraction exists when tissues are drawn in above the clavicle (shoulder girdle). Associated Clinical Signs When you assess respiration, it is important to assess for clinical signs of oxygenation. Hypoxia—Signs of hypoxia (inadequate cellular oxygenation) include pallor or cyanosis, restlessness, apprehension, confusion, dizziness, fatigue, decreased level of consciousness, tachycardia, tachypnea, and changes in BP. When evaluating cyanosis, the tongue and oral mucosa are the best indicators of hypoxia. Cyanosis of the nails, lips, and skin may be caused by hypoxia but may also be related to cold or reduced circulation in that area. Chronic hypoxia causes clubbing (loss of the nail angle) of the fingers. Cough—A cough is a forceful or violent expulsion of air during expiration. Coughs may be symptoms of allergic reactions, lung disease, respiratory infection, or heart conditions. Coughs may be constant (occurring frequently and consistently) or intermittent (occurring occasionally). The cough is productive if secretions are expectorated (coughed up). The cough is nonproductive or dry if no secretions are produced. A hacking cough is a series of dry coughs that occur together, whereas a whooping cough is a sudden, periodic cough that ends with a whooping sound on inspiration. KnowledgeCheck 18-4 How can you estimate a patient’s tidal volume? What is the range of normal for an adult’s respiratory rate? Besides the rate, what other characteristics of a patient’s respirations should you observe? What are common clinical signs associated with poor oxygenation? Arterial Oxygen Saturation The rate, quality, and depth of the respirations are indicators of the general health of the respiratory system. However, they do not measure the amounts of oxygen and carbon dioxide present in the blood—information that is essential for evaluating the effectiveness of respiratory effort. Two methods exist to measure O2 and CO2 blood levels. One method is invasive; the other is not. Arterial blood gas (ABG) sampling directly measures the partial pressures of oxygen, carbon dioxide, and blood pH, the gases in the arterial blood. This method requires the puncture of an artery followed by laboratory testing of the sample. It provides comprehensive data, but it is invasive, painful, time consuming, and relatively expensive. If you need more information about this diagnostic test, consult a medical-surgical nursing or laboratory tests text. Pulse oximetry is a noninvasive method of monitoring oxygenation with a device that measures oxygen saturation (an indication of the oxygen being carried by hemoglobin in the arterial blood). The oximeter emits light, and a photosensor placed on the patient’s finger or earlobe measures the light passing through the site and calculates a pulse saturation (SpO2) that is a good estimate of arterial oxygen saturation. The only risk in pulse oximetry is that clinicians may become too dependent on it or trust erroneous readings. Do not neglect the other aspects of holistic respiratory assessment. In many situations, oxygen saturation is monitored routinely along with the other VSs. To learn how to apply a pulse oximeter, see Procedure 33-2. ThinkLike a Nurse 18-8: Clinical Judgment in Action Mrs. Dowell has smoked two packs of cigarettes per day for 45 years. She has recently been diagnosed with pneumonia—an infection of the lungs. What VS assessments would be important for Mrs. Dowell, and why? Recall the patients in the Meet Your Patients scenario. Mr. Jackson is short of breath and struggling to breathe. His respiratory rate is 28 breaths/min. What else do you need to know about the patient situation? What is important and what is not important in this scenario? ANALYSIS/NURSING DIAGNOSIS NP As noted earlier, hypoxia refers to inadequate cellular oxygenation. It results from decreased oxygen intake, decreased ability of tissues to remove oxygen from blood, impaired ventilation or perfusion, impaired gas exchange between the blood and alveoli, or inadequate levels of hemoglobin. The following are two common alterations in respiration: Hyperventilation occurs when rapid and deep breathing result in excess loss of CO2 (hypocapnia). A patient who is hyperventilating may complain of feeling lightheaded and tingly. Causes of hyperventilation include anxiety, infection, shock, hypoxia, drugs (e.g., aspirin, amphetamines), diabetes mellitus, or acid-base imbalance. Hypoventilation occurs when the rate and depth of respirations are decreased and CO2 is retained or alveolar ventilation is compromised. Hypoventilation may be related to chronic obstructive pulmonary disease, general anesthesia, impending respiratory failure, or other conditions that result in decreased respirations. Two nursing diagnoses commonly used to describe various respiratory problems are Impaired Gas Exchange and Ineffective Breathing Patterns. For a more complete list, see Chapter 33. BLOOD PRESSURE BP is the pressure of the blood as it is forced against arterial walls during cardiac contraction. Systolic pressure is the peak pressure exerted against arterial walls as the ventricles contract and eject blood. Diastolic pressure is the minimum pressure exerted against arterial walls, between cardiac contractions when the heart is at rest. Adequate BP is essential for healthy tissue perfusion and is an important indicator of overall cardiovascular health. BP is measured in millimeters of mercury (mm Hg) and is recorded as systolic pressure over diastolic pressure (e.g., 110/74 mm Hg). Pulse Pressure Pulse pressure is the difference between the systolic and diastolic pressures. For a BP of 120/80 mm Hg, the pulse pressure is 40 mm Hg. It is an indication of the volume output of the left ventricle. Generally, the pulse pressure should be no greater than one-third of the systolic pressure, as in the example of a BP of 120/80 mm Hg, with a pulse pressure of 40 (1/3 × 120 = 40). Pulse pressure provides an indicator of heart health. A high pulse pressure may be a predictor of heart attacks or atherosclerosis, whereas a low pulse pressure can indicate poor heart functioning (Sheps, 2020). KnowledgeCheck 18-5 For a patient whose BP is 150/80 mm Hg, what is the pulse pressure? Is that normal? If so, explain. If not, what should the pulse pressure be? TheoreticalKnowledge knowing why To assess and support patients’ BP, you will need to understand how the concepts of systolic and diastolic BP contribute to tissue perfusion. Contraction of the heart (systolic pressure) forces a bolus of oxygenated blood into the arterial circulation to provide a continuous supply of oxygen to all body cells (perfusion). The heart then rests and refills with blood (diastolic pressure), which is pumped out to the tissues. Any factor that interferes with this cycle can cause impaired tissue perfusion. You will also need to know that an expert panel has classified a normal BP and the stages of hypertension (Whelton et al., 2018). How Are Blood Pressure Readings Categorized? The 2017 guidelines on the prevention, detection, evaluation, and treatment of high BP classify a “normal” BP as a systolic BP of less than 120 and a diastolic BP of less than 80. Table 18-6 identifies the classification of adult BP and the corresponding treatment. How Does the Body Regulate Blood Pressure? BP regulation is a highly complex process. It is influenced by three factors: cardiac function, peripheral vascular resistance, and blood volume. The body constantly regulates and adjusts arterial pressure to supply blood to body tissues via perfusion of the capillary beds. For in-depth discussion, see Chapter 34. Table 18-6 Classification of Adult Blood Pressure* CATEGORY SYSTOLIC (mm Hg) DIASTOLIC (mm Hg) FOLLOW-UP Normal Less than 120 and Less than 80 Encourage lifestyle modification if there are risk factors. Recheck in 1–2 years or sooner if there are risk factors. Elevated 120–129 and 80 or less Encourage lifestyle changes. Recheck in 3–6 months of nonpharmacological therapy. Stage I Hypertension 130–139 or 80–89 Low atherosclerotic cardiovascular disease (ASCVD): Encourage lifestyle changes. Recheck in 3–6 months of nonpharmacological therapy. High ASCVD: Manage with both nonpharmacological and antihypertensive drug therapy with repeat BP in 1 month. Stage II Hypertension 140 or higher or 90 or higher Evaluation by a primary care provider within 1 month of diagnosis; treat with nonpharmacological therapy and two different classes of antihypertensive drugs. Recheck BP in 1 month. Hypertensive Crisis Greater than 180 and/or Greater than 120 Consult your provider immediately. Note: If systolic and diastolic blood pressure fall within two categories, classify based on the higher category. Source: Data from Whelton, P., Carey, R., Aronow, W., Casey, D. E., Jr., Collins, K. J., Himmelfarb, C. D., DePalma, S. M., Gidding, S., Jamerson, K. A., Jones, D. W., MacLaughlin, E. J., Muntner, P., Ovbiagele, B., Smith, S. C., Jr., Spencer, C. C., Stafford, R. S., Taler, S. J., Thomas, R. J., Williams, K. A., et al. (2017). 2017 guideline for the prevention, detection, evaluation, and treatment of high blood pressure in adults, an update of the 2003 Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Journal of the American College of Cardiology, 23976. https://www.acc.org/~/media/Non-Clinical/Files-PDFs-Excel-MS-Word-etc/Guidelines/2017/Guid elines_Made_Simple_2017_HBP.pdf Whelton, P., Carey, R., Aronow, W., Casey, D. E., Jr., Collins, K. J., Himmelfarb, C. D., DePalma, S. M., Gidding, S., Jamerson, K. A., Jones, D. W., MacLaughlin, E. J., Muntner, P., Ovbiagele, B., Smith, S. C., Jr., Spencer, C. C., Stafford, R. S., Taler, S. J., Thomas, R. J., Williams, K. A., et al. (2018). 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Journal of the American College of Cardiology, 71(19), e127–e248. https://doi.org/10.1016/j.jacc.2017.11.006 Cardiac Function Recall that cardiac output is the volume of blood pumped by the heart per minute, and that it reflects the functioning of the heart. An increase in cardiac output causes an increase in BP; a decrease in cardiac output causes a decrease in BP (if all other factors remain the same). A change in either stroke volume or heart rate alters cardiac output. Increased Stroke Volume Conditions that increase cardiac output by increasing stroke volume include the following: Increased blood volume (e.g., as occurs during pregnancy) More forceful contraction of the ventricles (e.g., as occurs during exercise) Decreased Stroke Volume Conditions that decrease cardiac output by decreasing stroke volume include the following: Dehydration. Active bleeding. Damage to the heart (as seen after myocardial infarction, or heart attack). A very rapid heart rate (up to a point). While an increase in heart rate increases cardiac output, a very rapid heart rate limits the time allotted for the ventricles to fill, resulting in decreased stroke volume and, ultimately, decreased cardiac output. Peripheral Resistance Peripheral resistance refers to arterial and capillary resistance to blood flow as a result of friction between blood and the vessel walls. Increased peripheral resistance creates a temporary increase in BP. The amount of friction or resistance depends on blood viscosity, arterial size, and arterial compliance. The walls of the veins are thin and very distensible, so they have little influence on peripheral resistance and BP. Blood viscosity (thickness). Blood viscosity influences the ease with which blood flows through the vessels. Viscosity is determined by the hematocrit (the percentage of red blood cells in plasma). High hematocrit—elevates BP (Any disorder that increases hematocrit, e.g., dehydration, increases blood viscosity and, therefore, BP.) Low hematocrit—may reduce BP (A low hematocrit, as seen in anemia, lowers viscosity and may reduce BP.) Arterial size. The sympathetic nervous system controls vasoconstriction and vasodilation. The smaller the radius of a blood vessel, the more resistance it offers to blood flow. Constricted arteries prevent the free flow of blood and, subsequently, increase BP. Dilated arteries allow unrestricted flow of blood, thereby reducing BP. Arterial compliance (elasticity). Arteries with good elasticity can distend and recoil easily and adequately. When age- or disease-related changes in arterial structure cause a loss of elasticity, peripheral resistance, and possibly BP, increases. Arteriosclerosis (hardening of the arteries) is a common contributor to increased BP in middle-aged and older adults. Blood Volume The normal volume of blood in the body is about 5 liters (5,000 mL). A significant loss of blood, as occurs with hemorrhage, reduces vascular volume, and BP falls. When vascular volume is increased above the norm, as occurs with renal (kidney) failure and fluid retention, BP increases. What Factors Influence Blood Pressure? KEY POINT: BP normally changes from minute to minute with changes in activity or changes in body position. Therefore, you must establish BP patterns rather than relying on individual BP readings when determining whether a patient’s BP is normal or abnormal. This is even more important for older adults because their BP tends to fluctuate even more. The following are some factors that affect the BP: Developmental stage. An average newborn has a systolic BP of about 60 to 80 mm Hg and a diastolic BP of 40 to 50 mm Hg (Lowdermilk et al., 2019; Mersch, 2019). It increases gradually throughout childhood. A child’s or adolescent’s BP depends on body size; therefore, a smaller child or adolescent has a lower blood pressure than does a larger child or adolescent. Both systolic and diastolic BP continue to increase with age as a result of decreased arterial compliance and changes in the left ventricular wall. These normal aging process changes can lead to cardiovascular instability (Paneni et al., 2017). Sex. The average BP for men is slightly higher than that for women of comparable age. After menopause, a woman’s BP tends to increase, possibly due to a decrease in estrogen. Family history. A family history of hypertension markedly increases the likelihood of an individual developing hypertension. Lifestyle. Increased sodium consumption, smoking, and consumption of three or more alcoholic drinks per day have been shown to elevate BP. Caffeine may raise BP for a short while after ingestion, but it has no long-term effect on BP. Exercise. Physical fitness has been shown to reduce BP in many individuals. However, muscular exertion temporarily increases BP as a result of increased heart rate and cardiac output. You should, therefore, wait about 30 minutes before you assess the BP of someone who has been physically active. Body position. BP is higher when a person is standing than when they are sitting or lying down. Readings are higher if taken with the patient’s arm above heart level or if the arm is unsupported at the patient’s side. Seated readings are higher if the patient’s feet are dangling rather than resting on the floor or if the legs are crossed. Stress. Fear, worry, excitement, and other stressors cause BP to rise sharply because of sympathetic nervous system stimulation (fight-or-flight response). For example, “white-coat hypertension” occurs when a patient’s BP is elevated in the provider’s office or clinic—a situation in which they are likely to experience stress—but not at other times. However, if BP is consistently elevated with stress, treatment may be indicated. Pain. Pain often causes an increase in BP. However, severe or prolonged pain can significantly decrease BP. Race. People who are black have a higher rate of hypertension and a higher incidence of complications and hypertension-related deaths than other demographic groups (Whelton et al., 2018). Obesity. As a rule, obesity increases BP due to (1) the additional vascular supply required to perfuse the large body mass and (2) the resultant increase in peripheral resistance. Diurnal variations. Generally, BP varies according to the person’s daily schedules and routines. BP is lower while the person is sleeping and upon wakening, rises during the day, and drops again toward bedtime. Medications. Many medications alter BP. This effect may be intended, as with antihypertensive medications, or unintended, such as the drop in BP that often results when a patient receives pain medication. Many over-the-counter preparations, herbal products, and illicit drugs can affect BP. Teach your patient to consult with a pharmacist to identify the effect these products can have when taken with regularly prescribed medications. Diseases. BP may be affected by diseases that affect the circulatory system or any of the major organs of the body (e.g., the kidneys). Genetic variations/genes. Research has shown a link between genetic factors and hypertension (CDC, 2019b). ThinkLike a Nurse 18-9: Clinical Judgment in Action Evaluate the following adult blood pressures. Are they high, low, or normal? 116/90 mm Hg 80/50 mm Hg 184/102 mm Hg 140/90 mm Hg 40/0 mm Hg What theoretical knowledge did you use to evaluate the BPs? PracticalKnowledge knowing how Now that you understand the concept of perfusion and how BP is maintained and regulated, you are ready to gain practical knowledge of how to assess and support this aspect of physical functioning. ASSESSMENT NP BP may be assessed directly or indirectly. Direct Method In the direct method, a catheter is threaded into an artery under sterile conditions and attached to tubing that is connecte