Vital Signs and Body Temperature Regulation

Vital Signs

• Vital signs are four objective assessment data that indicate how well the body is functioning and are sensitive to physiological changes.
• They indicate the overall health status of the body.
• Vital signs include body temperature, pulse, respirations, and blood pressure.
• Body temperature is the balance between heat production and heat loss, measured in degrees.
• Normal body temperature range is 36.4 - 37.4°C (98.6°F - 99.3°F)
• Fahrenheit scale: 32°F as freezing point and 212°F as boiling point
• Centigrade scale: 0°C as freezing point and 100°C as boiling point

Body Temperature Regulation

• Hypothalamus: a brain structure that controls metabolic activities and temperature regulation.
• The hypothalamus sends signals to reduce temperature when heat is detected.
• Temperatures above 105.8°F (41°C) or below 93.2°F (34°C) indicate problems with the hypothalamic regulatory center.
• Extreme temperatures (above 110°F or below 84°F) can significantly decrease survival chance.

Types of Body Temperature

• Core temperature: Deep tissue temperature (thorax and abdomen) is relatively constant.
• Surface temperature: Skin and subcutaneous tissue temperatures fluctuate with environmental changes.

Ways of Heat Loss

• Radiation: Transfer of heat without direct contact.
• Conduction: Transfer of heat between molecules.
• Convection: Dispersion of heat by air currents.
• Evaporation: Continuous evaporation of moisture from the respiratory tract.

Body Temperature Terms

• Pyrexia (fever/hyperthermia): body temperature above normal range (38-40°C).
• Hyperpyrexia: very high temperature (above 40°C).
• Hypothermia: body temperature below normal range (below 35°C)
• Febrile: client with fever
• Afebrile: client without fever

Clinical Signs of Fever

• Increased heart rate
• Increased respiratory rate
• Shivering
• Pale skin
• Cyanosis (bluish discoloration) of nail beds
• Increased thirst
• Loss of appetite

Assessment Sites of Body Temperature

• Oral: Convenient and accessible, but can be inaccurate if the patient has recently eaten hot/cold food or drinks, is uncooperative, or has a seizure disorder or is a child. It is 0.5°C lower than rectal temperature.
• Rectal: Most reliable, but can be embarrassing and may injure the rectum. It is 0.5°C higher than oral temperature.
• Auxiliary: Safe and noninvasive for infants and unconscious patients, but takes longer for accurate reading. It is 0.5°C lower than oral temperature.
• Tympanic: Very fast and accessible, especially for children, but right and left measurements can vary, and too-deep insertion may damage the tympanic membrane.

Contraindications of Different Temperature Methods

• Oral: Uncooperative patients, unconscious patients, following oral trauma or surgery, patients receiving oxygen therapy (oxygen cools the mouth causing inaccurate temperature measurements).
• Rectal: Prolapsed rectum, following rectal surgery, severe diarrhea, bleeding tendency (e.g., leukemia, thrombocytopenia).
• Tympanic: Infected or draining ears, lesions or incisions adjacent to the ear.

Types of Thermometers

• Mercury glass thermometer
• Electronic thermometer
• Skin tape thermometer
• Tympanic thermometer

Instruments & Materials

• Thermometers (glass, oral, rectal)
• Electronic thermometers with protective sheaths
• Tympanic membrane thermometers with probe covers
• Disposable single-use chemical strip thermometers
• Lubricants for rectal and glass thermometers
• Two pairs of non-sterile gloves
• Tissues

Pulse

• Pulse: wave of blood created by ventricular contraction.
• Cardiac output = Stroke volume * Heart rate
• Types of pulse: peripheral (foot, hand) and apical (above the apex of the heart)
• Pulse deficit: difference between apical and radial pulse rates

Pulse Sites

• Temporal
• Carotid
• Radial
• Brachial
• Apical
• Popliteal
• Posterior tibial
• Dorsal pedis
• Femoral

Pulse Terms

• Tachycardia: pulse rate over 100 bpm
• Bradycardia: pulse rate below 60 bpm
• Normal heart rate: 60-100 bpm (infants have higher rates)
• Athletes: typically have lower resting pulse rates than average.
• Pulse rhythm: pattern of beats
• Dysrhythmia/arrhythmia: irregular pulse rhythm
• Pulse volume: force of blood with each beat

Respirations

• Respiration: the act of breathing.
• Normal respiratory rate: 12-20 breaths per minute (bpm)
• External respiration: exchange of gases (oxygen and carbon dioxide) between alveoli and blood.
• Internal respiration: exchange of gases between blood and body tissues.
• Muscles of respiration: diaphragm, intercostal muscles, and sternocleidomastoid.
• In females, chest movement is mainly observed.
• In males, abdominal movement is mainly observed.

Respiration Terms

• Eupnea: normal breathing rate and depth
• Bradypnea: slow breathing
• Tachypnea: fast breathing rate
• Dyspnea: difficulty breathing
• Orthopnea: ability to breathe only in a sitting or standing position

Respiration Secretions and Coughing

• Hemoptysis: blood in sputum
• Productive cough: cough with secretions
• Nonproductive cough: dry, harsh cough without secretions

Regulation of Respiration

• Controlled by the respiratory center in the medulla oblongata.
• Chemoreceptors in the medulla and peripheral areas (carotid and aortic bodies) are involved.

Blood Pressure

• Blood pressure: measurement of pressure exerted by blood flowing through arteries.
• Systolic blood pressure: pressure during ventricular contraction.
• Diastolic blood pressure: pressure when ventricles are at rest.
• Pulse pressure: difference between systolic and diastolic pressures.
• Mean arterial pressure (MAP): important indicator of tissue perfusion (1/3 systolic + 2/3 diastolic)
• Hypertension: consistently high blood pressure
• Hypotension: consistently low blood pressure
• Orthostatic hypotension: decrease in blood pressure when rising from sitting or lying down
• Accurate blood pressure measurements depend on patient posture (sitting, back supported, arm bared).
• Accurate BP measurements need quiet and a warm environment
• Taking readings should be done after 30 minutes of avoiding caffeine, tobacco, or alcohol.

Blood Pressure Measurement Equipment

• Cuffs (appropriate size for the patient)
• Manometers (types and calibration required)
• Non-invasive devices such as semi-automatic and automated devices

Blood Pressure Measurement Technique

• Use of Korotkoff sounds (and the identification of phases 1-5), to accurately identify systolic and diastolic pressures
• Positioning both arms, especially for patients with possible peripheral and arterial disorders
• Standing BP measurement should be considered for elderly and diabetic patients to assess orthostatic hypotension.
• Cuff should be positioned at heart level, respecting the patient's position,
• Use calibration

Ambulatory Blood Pressure Monitoring (ABPM)

• Takes several blood pressure readings over time.
• Helps with diagnoses of hypertension, clarify conditions (white coat, resistant or nocturnal), and define uncontrolled BP.
• Used in national health surveys to accurately estimate hypertension prevalence.

Home Blood Pressure Measurement

• Encourages patient involvement in monitoring their condition
• Useful for assessing patients with hypertension, suspected non-adherence, white coat hypertension, or masked hypertension.
• Average BP equal to or above 135/85 mmHg requires further attention.

General Guidelines for Blood Pressure Measurement

• Avoid caffeine, tobacco, and alcohol for 30 minutes before measurements.
• Sit or lie down for 3-5 minutes.
• Use a properly sized cuff
• Ensure the cuff center corresponds with the brachial artery for the arm position
• Keep arm at heart level during measurements

Further Notes on Vital Signs

• Correct assessment techniques, including equipment selection and patient preparation are critical for accuracy.
• Additional specific guidelines could be recommended based on patient and disease situations.