Critical care medicine or intensive care is a branch of medicine where the patient is on life support or organ support systems. Usually the patients in the critical care unit are gravely ill and may not survive. Critical care medicine is not about preventing death in many cases. Instead critical care medicine is about making the patient as comfortable as possible.

Nurses and doctors in the critical care medicine branch have to monitor the ventilation machines and other organ machines to ensure the patient will remain breathing. For patients who are not going to make it the nurses and doctors may turn the machines off at the request of the family. At other times in critical care medicine a person may be on the machines in a coma.