"Critical" is one of the five words that can be used to inform other medical professionals, family members or members of the media of a patient's condition. It is the most serious of the five conditions. The other four conditions are "undetermined," "good," "fair" and "serious."
According to the American Hospital Association (AHA), a patient who has been declared to be in critical condition has some vital signs that are above or below normal and/or are not stable. For example, a car-wreck victim may have a blood pressure measurement that fluctuates between extreme highs and lows and has a head injury that is causing intermittent unconsciousness.
A patient listed in critical condition also may be unconscious. She may be in a coma or fully awake. Unconsciousness alone is not an indicator of a patient being in critical condition.
Critical, but Stable
Doctors and nurses use the term "critical, but stable" to distinguish patients with life-threatening ailments or injuries from those who have a better prognosis. Because this term is contradictory, it is recommended by the AHA that medical professionals do not use it in when speaking to families or the media, as it can be misleading