Intensive care unit. Doctor uses a stethoscope to check the heartbeat of a man in an intensive care unit. Attached to the man's body is a pulse meter (attached to the man's finger, lower right) and a blood gas probe (not seen). A vital signs monitor (top right corner) records the patient's blood pressure, heart rate, blood oxygen and respiration rate. If any of these signs become abnormal an alarm will sound. An oxygen mask is attached to the patient's face. This kind of care unit is required for patients who are recovering from a heart attack, major surgery or are unconscious.