Critical care involves the care and treatment of individuals with severe, potentially life-threatening illnesses. It is often linked with pulmonary medicine because respiratory failure is a key risk factor for these patients. Most critical care patients reside in the Clinic's intensive care unit (ICU). At Lahey Clinic, an intensivist (a physician with special qualifications in critical care medicine) leads a multidisciplinary health care team in the care of critically ill patients. This program uses both innovative and established technologies in critical care and embraces the latest evidence-based practices in the treatment of critical care patients. A special focus of the program is the attention given to methods of weaning patients from mechanical ventilation and helping family members cope with the dilemma of deciding whether or not and when to withdraw or withhold life support from a hopelessly sick patient.