Vital signs (also known as vitals) are a group of the four to six most crucial medical signs that indicate the status of the body's vital (life-sustaining) functions. These measurements are taken to help assess the general physical health of a person, give clues to possible diseases, and show progress toward recovery. The normal ranges for a person's vital signs vary with age, weight, sex, and overall health.
There are four primary vital signs: body temperature, blood pressure, pulse (heart rate), and breathing rate (respiratory rate), often notated as BT, BP, HR, and RR. However, depending on the clinical setting, the vital signs may include other measurements called the "fifth vital sign" or "sixth vital sign". Vital signs are recorded using the LOINC internationally accepted standard coding system.
Early warning scores have been proposed that combine the individual values of vital signs into a single score. This was done in recognition that deteriorating vital signs often precede cardiac arrest and/or admission to the intensive care unit. Used appropriately, a rapid response team can assess and treat a deteriorating patient and prevent adverse outcomes.
Primary vital signs
There are four primary vital signs which are standard in most medical settings:
Body temperature
Heart rate or Pulse
Respiratory rate
Blood pressure
The equipment needed is a thermometer, a sphygmomanometer, and a watch. Although a pulse can be taken by hand, a stethoscope may be required for a patient with a very weak pulse.
Temperature
Temperature recording gives an indication of core body temperature which is normally tightly controlled (thermoregulation) as it affects the rate of chemical reactions. Body temperature is maintained through a balance of the heat produced by the body and the heat lost from the body.
Temperature can be recorded in order to establish a baseline for the individual's normal body temperature for the site and measuring conditions.
Temperature can be measured from the mouth, rectum, axilla (armpit), ear, or skin. Oral, rectal, and axillary temperature can be measured with either a glass or electronic thermometer. Note that rectal temperature measures approximately 0.5 °C higher than oral temperature, and axillary temperature approximately 0.5 °C less than oral temperature. Aural and skin temperature measurements require special devices designed to measure temperature from these locations.
While 37 °C (98.6 °F) is considered "normal" body temperature, there is some variance between individuals. Most have a normal body temperature set point that falls within the range of 36.0 °C to 37.5 °C (96.5–99.5 °F).
The main reason for checking body temperature is to solicit any signs of systemic infection or inflammation in the presence of a fever. Fever is considered temperature of 37.8 °C or above. Other causes of elevated temperature include hyperthermia, which results from unregulated heat generation or abnormalities in the body's heat exchange mechanisms.
Temperature depression (hypothermia) also needs to be evaluated. Hypothermia is classified as temperature below 35 °C (95 °F).
It is also recommended to review the trend of the patient's temperature over time. A fever of 38 °C does not necessarily indicate an ominous sign if the patient's previous temperature has been higher.