Vital signs are the four core bodily functions that are monitored in critical patients, generally with electronic monitors that sound an alarm when one of the signs is outside even an extreme range. The four signs are:
- Heart rate: Generally the pulse detected at the tip of the right index finger. This tends to be a more reliable indicator of health and circulation than the rate at the heart. It should not fall below 50 or rise above 120 in a patient at rest, and should remain steady.
- Respiration rate: This should be about 15 per minute. Too fast indicates respiratory distress. Too low indicates impending respiratory arrest.
- Blood pressure: measured at regular intervals by an automatically inflated cuff around the upper right arm. Ideally, it should be 120/80, but any lower figure from 60-100 is generally acceptable. If it drops lower, the patient will probably go into cardiac arrest. Too high and the patient will most likely suffer a stroke.
- Blood oxygenation: Should remain well over 90% (99-100% is normal). If it drops lower, the patient will most likely suffer cardiac arrest.