Measuring Vital Signs - Vocabulary Flashcards

Key vocabulary terms and concise definitions covering vital signs concepts, measurement, interpretation, and related mechanisms from the lecture notes.

Vital signs

The four primary physiological measurements (temperature, pulse, respirations, and blood pressure) used to assess a patient’s essential body functions.

Thermoregulation

The body's process of maintaining a stable internal temperature by balancing heat production and heat loss, regulated by the hypothalamus.

Core temperature

Temperature of the body's interior (e.g., viscera); the most accurate indicator of true body temperature, higher than surface readings.

Surface temperature

Temperature measured at sites like oral, axillary, or skin; reflects skin temperature and is typically cooler than core temperature.

Hypothermia

Abnormally low core body temperature, usually below 35°C (95°F).

Hyperthermia

Elevated body temperature due to heat gain or impaired heat loss, not reset by the hypothalamus (includes heat stroke).

Fever (pyrexia)

Oral temperature >37.8°C (100°F) or rectal temperature >38.3°C (101°F); body's defense where the set point is raised by pyrogens.

Fever—pyrogens

Substances (e.g., interleukin-1) that trigger fever by raising the hypothalamic set point.

Set point

The hypothalamic thermostat setting that determines the body's acceptable temperature; raised during fever.

Hyperpyrexia

Very high fever, typically >41.0°C (105.8°F); dangerous and requires intervention.

Fever phases

phases: initial (chills as temp rises), course (fever remains high), defervescence (temp returns to normal with sweating).

Intermittent fever

Fever that alternates regularly between fever and normal or below-normal temperatures within 24 hours.

Remittent fever

Fever with fluctuations greater than 2°C (3.6°F) above normal within 24 hours.

Constant fever

Fever that remains above normal with little fluctuation.

Relapsing (recurrent) fever

Short periods of fever alternating with normal temperatures, each lasting 1–2 days.

Fahrenheit–Celsius conversion

To convert F to C: (F − 32) × 5/9; to convert C to F: (C × 9/5) + 32.

Core vs surface temperature difference

Core temperature is typically 0.6°C–1.2°C (1°F–2°F) higher than surface temperature.

Temperature measurement sites

Oral, rectal, axillary, tympanic membrane, and temporal artery; core sites include pulmonary artery (gold standard).

Radiation

Heat loss mechanism through emission of infrared waves from warmer surfaces to cooler surroundings.

Convection

Heat transfer by movement of air or water; used clinically to raise/lower body temperature.

Evaporation

Heat loss when water evaporates from skin or mucous membranes; contributes to cooling.

Conduction

Heat transfer through direct contact with a cooler surface.

Pulse

Rhythmic expansion and recoil of an artery as blood is pumped by the heart; measured in beats per minute.

Cardiac output

Total volume of blood pumped per minute; CO = stroke volume × heart rate.

Stroke volume

Amount of blood ejected by the left ventricle with each heartbeat (about 70 mL in healthy adults).

Pulse pressure

Difference between systolic and diastolic BP; PP = systolic − diastolic. Indicates left ventricular output.

Bradycardia

Pulse rate below 60 beats per minute.

Tachycardia

Pulse rate above 100 beats per minute.

Apical pulse

Pulse heard or felt at the apex of the heart; most accurate site, used when peripheral pulses are unreliable.

Pulse deficit

Difference between apical and peripheral (e.g., radial) pulse rates, indicating not all apical beats are transmitted or felt.

Dysrhythmia

Abnormal heart rhythm; irregular rhythms may require ECG assessment.

Peripheral pulse

Pulse felt at arteries away from the heart (e.g., radial, brachial, carotid).

Respirations

Breathing rate, the number of breaths per minute; can indicate overall respiratory function.

Eupnea

Normal, unlabored breathing; usually 12–20 breaths per minute in adults.

Bradypnea

Slow breathing; fewer than 10 breaths per minute.

Tachypnea

Rapid breathing; more than 24 breaths per minute.

Cheyne‑Stokes respiration

Abnormal breathing pattern with gradual changes in depth followed by apnea.

Biot respiration

Irregular breathing with varying depth and periods of apnea.

Kussmaul respiration

Very deep and labored breathing pattern often associated with metabolic acidosis.

Apnea

Absence of breathing.

Hypoxia

Inadequate cellular oxygenation in tissues.

Hyperventilation

rapid and deep breathing causing excessive CO2 loss (hypocapnia).

Hypoventilation

Decreased breathing rate or depth with CO2 retention.

Oxygen saturation (SpO2)

Percentage of hemoglobin binding sites occupied by oxygen in arterial blood; measured noninvasively by pulse oximetry.

Pulse oximetry

Noninvasive method to estimate arterial oxygen saturation using a sensor on a fingertip or earlobe.

ABG (arterial blood gas)

Invasive test measuring O2, CO2, and blood pH in arterial blood; provides comprehensive gas exchange data.

Arterial blood pressure (BP)

Force of blood against arterial walls during the cardiac cycle; measured in mm Hg.

Systolic pressure

Peak pressure during ventricular contraction (systole).

Diastolic pressure

minimum arterial pressure during heart relaxation (diastole).

Normal BP (adult)

Less than 120 systolic and less than 80 diastolic (reference values for normal BP).

Elevated BP

Systolic 120–129 and diastolic <80 mm Hg.

Stage I hypertension

Systolic 130–139 or diastolic 80–89 mm Hg.

Stage II hypertension

Systolic ≥140 or diastolic ≥90 mm Hg.

Hypertensive crisis

Systolic >180 and/or diastolic >120 mm Hg requiring urgent evaluation.

Orthostatic (postural) hypotension

Drop of ≥10 mm Hg diastolic or ≥20 mm Hg systolic within 2–5 minutes of standing.

Direct BP measurement

Invasive arterial BP measurement via arterial catheter with continuous monitoring.

Indirect BP measurement

Noninvasive BP measurement (auscultation or palpation) using a cuff and sphygmomanometer.

Korotkoff sounds

Five sounds heard during auscultation of BP; used to determine systolic and diastolic pressures.

Auscultatory gap

Temporary disappearance of Korotkoff sounds during cuff deflation; can cause misreading if not accounted for.

Cuff/bladder size

Cuff width about two-thirds of arm length; bladder encircles ~80% of arm; wrong size can cause large measurement error.

Sphygmomanometer

Device with cuff, bulb, and manometer used to measure BP.

Stethoscope

Instrument used to listen to heart and vascular sounds; contains bell and diaphragm.

Temperature measurement sites

Temporal artery, tympanic membrane, oral, rectal, axillary; selection depends on safety, accuracy, and patient condition.

Baseline vital signs

Initial measurements used to establish a patient’s normal reference point for comparison over time.

Pain as a vital sign

Pain is often considered the fifth vital sign; its assessment is multidimensional and context-dependent.