Temperature Regulation & Measurement

• Vital signs (VS), also called signs of life or cardinal signs, are indicators used to monitor the body’s function.
• Traditional vital signs include body temperature (T), pulse rate (PR), respiration rate (RR), and blood pressure (BP).
• Many health agencies have designated pain as the fifth vital sign.
• Arterial blood oxygen saturation (SO2) also viewed as a vital sign.
• Special graphic forms are used to record VS to facilitate data comparison at a glance.

When to measure vital signs

• Upon admission or discharge from a health care facility
• When a client has a change in health status, such as loss of consciousness, chest pain or feeling hot
• Before, during, and after surgery or an invasive procedure
• Before and after administering medications/interventions that could affect vital signs
• Before, during, and after a transfusion of blood and blood products
• At the start of every shift or as routine nursing care

Body Temperature (T)

• Reflects the balance between heat produced by metabolism and heat lost.
• Heat is lost through radiation, conduction, convection, and evaporation.

Kinds of body temperature

• Core temperature: Temperature of deep body tissues.
  • It remains constant, the core internal temperature does not vary more than 0.77°C and is generally about 37°C.
• Surface temperature: Temperature of the skin, subcutaneous tissue, and fat
  • Rises and falls in response to the environment.

Factors affecting body's heat production

• Basal Metabolic Rate (BMR): Rate of energy utilization required to maintain essential activities such as breathing.
  • Decreases with age, higher in younger individuals
• Muscular activity: Increases metabolic rate.
• Thyroxine output: Increased thyroxine output increases BMR.
• Epinephrine, norepinephrine, and sympathetic stimulation: Increases the rate of cellular metabolism.
• Fever: Increases the rate of cellular metabolism.

Factors affecting body temperature

• Age: Infants are greatly influenced by environmental temperature and must be protected from extreme changes Metobolic rate is higher in younger persons and decreases with old age.
• Children's temperature varies more than adults until puberty.
• Older adults are at risk of hypothermia due to inadequate diet, loss of subcutaneous fat, lack of activity, and reduced thermoregulatory efficiency.
• Variations: Body temperature normally changes throughout the day (1.0°C between early morning and late afternoon).
  • Typically highest from 4:00-6:00 PM, and lowest during sleep (4:00-6:00 AM).
• Physical activity: Hard work or exercise can increase BMR and cause body temperature to rise.
• Gender (Hormones): Women usually experience more hormone fluctuations. Progesterone secretion at the time of ovulation raises body temperature by about 0.3-0.6°C.
• Stress: Stimulation of sympathetic nervous system can increase the production of epinephrine and norepinephrine.
• Environment: High environmental temperature, humidity, and a hot bath can elevate body temperature. Decreased temperature, lack of clothing or shelter, or submersion in cold water can lower body temperature.

Alterations in Body Temperature

• Normal adult range: 36.0°C - 37.5°C (96.8°F - 99.5°F).

Pyrexia, hyperthermia, fever

• Core body temperature above the usual range (greater than 38°C or 100.4°F)
  • Hyperpyrexia: Very high fever, above 41°C or 105.8°F
  • Febrile: A client who has a fever.
  • Afebrile: A client who does not have a fever.

Hypothermia

• Core body temperature below the lower limit of normal (less than 36°C or 96.8°F).
  • Three physiological mechanisms: excessive heat loss, inadequate heat production, and impaired hypothalamic thermoregulation

Clinical Manifestations of Hypothermia

• Decreased body temperature, pulse rate, and respiratory rate
• Severe shivering
• Feelings of cold and chills
• Pale, cool, waxy skin
• Frostbite
• Hypotension
• Decreased urinary output
• Lack of muscle coordination
• Disorientation, drowsiness progressing to coma

Nursing Interventions for Clients with Hypothermia

• Provide a warm environment and bath
• Provide dry clothing, warm blankets, and pads
• Keep limbs close to the body
• Cover the client’s scalp
• Provide warm oral fluids
• Administer warm intravenous (IV) fluids as ordered

Types of Fever

• Intermittent: Body temperature alternates at regular intervals between fever and normal/subnormal temperature.
• Remittent: Wide range of temperature fluctuations (greater than 2°C) above normal over a 24-hour period.
• Relapsing (Recurrent): Temperature returns to normal for 1-2 days, followed by 1-2 days of higher temperature.
• Constant (Sustained): Body temperature fluctuates minimally but remains above normal.

Clinical manifestations of fever

• Course (plateau phase): Absence of chills, skin feels warm, photosensitivity, glassy-eyed appearance, Increased pulse and respiratory rate.
• Onset (cold or chill phase): Increased heart rate and respiratory rate, shivering, pallid, cold skin, complaints of feeling cold, cyanotic nail beds, cessation of sweating.
• Flush phase: Skin appears flushed and feels warm, sweating, decreased shivering, possible dehydration. Other possible symptoms
• Increased thirst, mild to severe dehydration
• Drowsiness, restlessness, delirium, or convulsions
• Herpetic lesion of the mouth
• Muscle weakness, malaise and aching.

Nursing Interventions for Clients with Fever (Goal)

• support the body's normal physiological processes, provide comfort, and prevent complications.
• Monitor vital signs, skin color and temperature, WBC count and relevant lab tests
• Remove excess blankets when client feels warm, but provide extra blankets when chilled
• Encourage adequate nutrition/fluids (2500-3000 ml/day), measure intake and output
• Reduce physical activity, administer antipyretics, and maintain oral hygiene
• Provide a tepid sponge bath and dry clothing/bed linens

Sites/Methods for Assessing Body Temperature

• Oral Site (Orally)
  • Advantage: Accessible & convenient
  • Disadvantage: Inaccurate if client ingested hot/cold food or smoked. Not applicable for patients who have oral & nose pathologies, receiving oxygen or unable to breathe through the nose / children or confused patients or thermometers break

Rectal Site

• Advantage: Accurate
• Disadvantage: Unpleasant, difficult for clients who cannot turn, may injure the rectum, presence of stool may interfere, contraindicated after rectal surgery in clients with diarrhea, or cardiac patients. Also has a risk of Valsalva's maneuver.

Axillary Site

• The preferred site for newborns and infants
• Advantage: Safe, noninvasive, and easily accessible
• Disadvantage: Least accurate.

Tympanic Membrane Site

• Advantage: Readily accessible, reflects core temperature, and very fast
• Disadvantage: Uncomfortable, risk of injury, and presence of cerumen can affect reading

Temporal Artery Site

• Used in newborns and infants
• Advantage: Safe, noninvasive, and very fast
• Disadvantage: Technique variation needed with perspiration

Skin Site

• Forehead, abdomen
• Advantage: Easily accessible, available in disposable strips
• Disadvantage: Less accurate, perspiration interferes

Temperature Scales

• The Centigrade or Fahrenheit scale is used to measure and record body temperature.

Conversions

• Celsius (Centigrade) to Fahrenheit: Multiply by 9/5 & add 32
• Fahrenheit to Celsius: Deduct 32 & multiply by 5/9

Pulse Rate (PR)

• Pulse is a wave of blood created by the contraction of the left ventricles of the heart; it reflects how often the heart beats per minute
• Normal adult pulse rate range: 60-100 bpm; Newborn range: 120-140 bpm.

Cardiac output

• Blood volume pumped into the arteries by the heart in one minute.
• Measured by multiplying heart rate by stroke volume; adult on rest pumps 5 liters of blood a minute.
• Stroke volume: Amount of blood that exits the left ventricle and enters the aorta with each ventricular contraction (60 to 70 ml).
• Pulse volume: Force of blood with each beat.
• Pulse rhythm: The spacing/regularity of beats. Irregular if skips beats.

Dysrhythmia or arrhythmia

• Pulse with an irregular rhythm and force
• Sign of some forms of heart disease or overactive thyroid gland.
• Peripheral pulse: Reflects HR and adequacy of circulation to a body part such as an extremity away from the heart

Altered in Pulse Rate

• Tachycardia: Pulse rate above normal (100 bpm in adults).
• Bradycardia: Pulse rate less than normal (60 bpm in adults).

Methods for Measuring Pulse Rate

• Palpation: Feeling with fingers (do not use the thumb)
• Auscultation with a stethoscope: Listening to sounds at the apex of the heart provides the most accurate pulse rate.
• Doppler ultrasound stethoscope: Used for peripheral pulses difficult to assess.

Pulse Measurement Sites

• Radial: On the thumb side of the inner aspect of the wrist.
• Temporal: Superior and lateral to the eye when the radial pulse is inaccessible.
• Brachial: Inner aspect between biceps and triceps muscles, used to measure blood pressure and during cardiac arrest in infants. Femoral: Alongside the inguinal ligament, for cardiac arrest/shock, and leg circulation.
• Carotid: Under lower jaw in neck. Used during cardiac arrest/shock in adults to determine circulation to the brain.
• Popliteal: Behind the knee, used to determine circulation to the lower leg.
• Posterior Tibial: Medial surface of the ankle, circulation to the foot.
• Dorsalis Pedis (Pedal): Over instep, used to determine circulation to the foot.

Apical

• Apex of heart (in adult), on the left side of the chest.
• Indicated for clients with irregular/unavailable peripheral pulse, cardiovascular/pulmonary/renal diseases, medication affecting heart rate, and infants/children (up to 2-3 years).

Notes on pulse

• Normal pulse characteristics: quality, rate, rhythm, volumes, arterial wall elasticity, and bilateral equality.
• Regular rhythm: Count for 15 seconds and multiply by 4.
• Irregular: Count pulse for a full 60 seconds. Do not disrupt cerebral flow when assessing carotid pulse, apply light pressure to only one carotid artery.
• Pulse Deficit: Difference between apical and radial rates.

Factors Affecting Pulse Rate

• Age: Pulse rate decreases with age.
• Gender: After puberty, males have slightly lower than females.
• Exercise: Pulse rate increases with activity due to increased BMR, oxygen demand, stroke volume, and cardiac output.
• Medication: Decrease PR include digoxin/antihypertensives while epinephrine/theophylline and atropine increase PR.
• Body Temperature: With a fever, each degree of Fahrenheit increases heart rate by 10 bpm. When the body cools, each degree decreases the heat rate by 10 bpm.
• Blood Volume: Hypervolemia causes a full and bounding PR whereas Hypovolemia weakens and increases the PR.
• Stress, Fear, Anxiety, and Severe Pain: Increase HR as a result of sympathetic stimulation.
• Position: Pulse rate increases upon sitting or standing due to blood usually pooling in the dependent vessels.
• Pathological Processes: Obstructive pulmonary or cardiovascular diseases can affect the pulse rate.

Respiration Rate RR

• Act of breathing.
• Normal respiration is: Slightly observable, quiet, effortless, regular, and automatic.

Respiration Defined

• External respiration: Exchange of O2 and CO2 between alveoli of the lungs.
• Internal respiration: Interchange of O2 and CO2 between the circulating blood and cells.
• Inspiration: Intake of air into the lungs
• Expiration: Breathing out (movement of gases from the lung to the atmosphere)
• Ventilation: Movement if air in and out of the lungs
• Respiratory rhythm: Regularity of expiration and inspiration (regular or irregular)
• Eupnea: Normal breathing rate and depth.

Type of Breathing

• Costal (thoracic) breathing: Involves intercostal muscle and other accessory muscles.
• Diaphragmatic (abdominal) breathing: Involves the contraction and relaxation of the diaphragm.

Regulation of Breathing

• Respiratory centers in the medulla oblongata and the pons of the brain
• Chemoreceptors are in the medulla and in the carotid/aortic bodies

Assessing Respiration

• Observe chest wall expansion and bilateral symmetrical movement of the thorax. Normal adult RR: 12-20 breaths/minute.
• Respiratory depth can be established by watching the movement of the chest or normal, deep or shallow.
• Deep: large volume of air is inhaled and exhaled, inflating most of the lung.
• Shallow: Involves the exchange of a small volume of air, minimal use of lung tissue.

Factors Affecting Respiration

• Factors increase the respiratory rate: exercise, stress, anxiety, acute pain, fever, increased temperature, decrease oxygen concentration, anemia, respiratory and heart disease, some medications, smoking.
• Factors decrease the respiratory rate include: decreased environmental temperature, certain medication (e.g narcotics, sedative), increased intracranial pressure and old age.

Altered Breathing Patterns and Sounds

• Altered Breathing Rate
  • Bradypnea: Abnormally slow respiration (less than 10 breaths/minute)
  • Tachypnea: Abnormally fast respiration (greater than 20 breathes/minute)
  • Apnea: Cessation or absence of breathing
• Altered Breathing Volume
  • Hypoventilation : shallow respiration
  • Hyperventilation: over expansion of the lungs, characterized by very deep, rapid respiration.
• Altered Breathing Effort Dyspnea: Use of accessory muscles in the chest/neck
  • Orthopnea: Able to breathe only in an upright position.
• Secretion And Coughing
  • Hemoptysis: Presence of blood in sputum
  • Productive cough: Cough with expectorated secretions Nonproductive cough: A dry, harsh cough without secretion.
• Breath Sounds
  • Stridor: Harsh sound during inspiration with laryngeal obstruction.
  • Wheeze: Continuous, high-pitched musical squeak/whistling sound when air moves with a narrowed airway.
• Respirations are under both involuntary and voluntary control.
• NOTE*
• Count Regular respiratory rhythms for 30 second and multiply by 2/ count irregular respiratory rhythms for a full minute.
• Use other vital signs to decide the clients condition who falls to fewer than 10 shallow breaths per minute as an adult

Blood Pressure (BP)

• Measurement of the force of moving blood against arterial walls.
• Measured in millimeters of mercury (mm Hg); Atypical BP for a healthy adult should be no more than 120/80 mmHg.
• Arterial blood pressure: Measure of the exerted pressure as blood flows through the arteries.
• Systolic pressure: Height of the blood wave
• Diastolic pressure: Phase in which the ventricles are at rest. Lower pressure.
• Pulse pressure: The difference between diastolic and systolic pressure (normally, about 40 mmHg).
• Consistently elevated pulse pressure occurs in arteriosclerosis; low pulse pressure occurs in severe heart failure.

Hemodynamic Regulators for BP Control

• Peripheral vascular resistance: Capillaries diameter/ar Terioles capacity, this can increase BP; especially diastolic BP (capillaries)
• Pumping action of the heart: Lower cardiac output; decrease BP and higher cardiac output; increased BP Blood volume: Decrease when fluids in arteries decrease during Hemorrhage/ dehydration, conversely, increase volume; increase BP
• Blood viscosity: High proportion of RBCs to blood plasma; increased BP

Factors Affecting Blood Pressure

• Age: Pressure rises with age, peaking at puberty and then declining
• Exercise and Physical Activity: BP rises with exercise and physical activity
• Stress: BP rises under sympathetic nerves system; increasing cardiac output.
• Medical conditions and medication: Any condition affecting the cardiac output has a direct effect on BP and arteries has a direct effect on the BP.
• Race Sex: After puberty: females have lower BP than males
• Obesity: Predisposed to hypertension
• Diurnal Variation: BP is lowest the early morning then rises.
• Temperature: Fever can increase BP and External heat causes vasodilation and decreases BP, external cold causes vasoconstriction and increases BP. Position: BP is higher when a person is standing
• Diurnal variation: BP usually lowest at in early morning

Methods for Assessing BP

• Direct: Catheter inserted directly into the brachial, radial, or femoral artery
• Indirect (noninvasive): Auscultatory and palpatory methods

Blood Pressure Assessment Sites

• The Common Site: Client's upper arm (brachial artery)
• Radial: Lower arm as possible for infants or clients w/large upper arms
• Thigh (popliteal artery): BP cant be measured on either arm, to compare with BP in the other thigh.
• Do not measure where there, Injury, surgically removed or has Intravenous in the limb.

Classification of Blood Pressure

Alterations in Blood Pressure

• Hypertension: The Systolic and or diastolic is higher than 140 or 90
• Hypotension: BP below normal. Systolic reading consistantly is between 85 to 110

Explore the principles of body temperature regulation, measurement techniques, and factors affecting temperature. Review contraindications, accurate methods for newborns, and the influence of the sympathetic nervous system. Understand how the Basal Metabolic Rate affects temperature.