Vital Signs and Temperature Basics

Vital signs are measurements of the most basic body functions including temperature, pulse, respiration, and blood pressure.
Pain is the 5th vital sign.
Vital signs can be observed, measured, and monitored to assess an individual's functioning.
Normal ranges for vital signs fluctuate with age and medical conditions.
Vital signs are valuable in detecting or monitoring health problems.

Body temperature regulation requires the coordination of multiple body systems.
Heat production needs to equal heat loss for core temperature to remain stable.
The hypothalamus, located in the brain, acts as the body's thermostat, detecting small temperature changes and triggering appropriate responses in the nervous, circulatory, skin, and sweat gland systems to maintain homeostasis.
Normal body temperature for a healthy individual ranges from 97.8°F (36.5°C) to 99°F (37.2°C).
Body temperature can be monitored using oral, axillary, rectal, skin-site (forehead, abdomen), and ear-site (tympanic membrane) methods.

Basal metabolic rate (BMR) is the rate at which the body uses energy for essential activities.
Muscle activity, including shivering, significantly increases metabolic rate.
Thyroxin output increases cellular metabolism throughout the body.
Epinephrine and sympathetic stimulation immediately increase cellular metabolism in various tissues.
Age and gender impact temperature.
Diurnal variation (daily fluctuations) affects temperature.
Exercise can raise body temperature.

Pyrexia, hyperthermia, or fever is a core body temperature above the usual range (> 38 °C or 100.4 °F).
Hyperpyrexia is a very high fever above 41°C or 105.8 °F
Febrile indicates a client with a fever, while afebrile indicates a client without a fever.

Hypothermia is a core body temperature below the lower limit of normal (< 36°C or 96.8 °F).
Three physiological mechanisms contribute to hypothermia: excessive heat loss, inadequate heat production, and impaired hypothalamic thermoregulation.

Onset (cold or chill phase): Increased heart rate, increased respiratory rate, shivering, pallid and cold skin, complaints of feeling cold, cyanotic nail beds, cessation of sweating.
Course (plateau phase): Absence of chills, warm skin, photosensitivity, glassy-eyed appearance, increased pulse and respiratory rate, increased thirst, dehydration.

Pulse is a wave of blood created by the contraction of the left ventricle of the heart.
Provides data about cardiovascular status.
Normal adult pulse ranges from 60 to 100 beats per minute.
Bradycardia is a heart rate below 60 beats per minute in an adult.
Tachycardia is a heart rate above 100 beats per minute in an adult.
Pulse rhythm indicates the regularity of the heartbeat: regular (evenly spaced beats), irregular (unevenly spaced beats), dysrhythmia (arrhythmia, irregular rhythm due to early, late, or missed heartbeats).

Factors increasing pulse rate: pain, fever, stress, exercise, bleeding, low blood pressure, some medications
Factors slowing pulse rate: rest, increasing age, thin body size, some medications, thyroid gland disturbances.

Pulmonary ventilation (breathing) involves the movement of air in and out of the lungs.
Inspiration (inhalation) is breathing in.
Expiration (exhalation) is breathing out.

Normal breathing is automatic and involuntary.
Resting adults have a normal respiratory rate of 12 to 20 breaths per minute, while infants have a rate of 30 to 60 breaths per minute.
Tachypnea is an abnormally fast respiratory rate (above 20 breaths per minute in adults).
Bradypnea is an abnormally slow respiratory rate (below 12 breaths per minute in adults).
Apnea is the absence of respirations and is often described by the duration of no respirations.

Blood pressure is the force exerted by blood against the blood vessel walls.
Systemic arterial blood pressure is commonly measured clinically.
Blood pressure is expressed in millimeters of mercury (mm Hg).
Normal BP is 120/80 mmHg.
Hypertension is a systolic blood pressure above 120 mm Hg or 20 to 30 mm Hg higher than the client's typical systolic pressure.
Hypotension is a systolic blood pressure below 90 mm Hg or 20 to 30 mm Hg lower than the client's typical systolic pressure.

Direct method: Involves a catheter placed inside an artery, providing continuous BP readings, typically used in critical care settings.
Indirect method: Uses an inflatable cuff to temporarily block arterial blood flow in a limb. As the cuff deflates and flow returns, BP is determined by palpation, auscultation, or oscillations.