This document discusses critical care nursing and the care of critically ill patients. It defines critical illness as a life-threatening condition requiring intense and vigilant nursing care. Critical care nurses work in intensive care units (ICUs) and emergency departments, caring for patients with issues like respiratory failure, shock, neurological problems, infections, or post-surgery using advanced technology and equipment. The needs of critically ill patients and their families are also outlined, such as physical, emotional and psychological stress from the ICU environment.