Table Some Causes of Agitation or Confusion in Critical Care Patients Mechanism Examples Underlying disorder Head injury Shock Toxin ingestion Pain and discomfort (eg, caused by injuries, surgical procedures, endotracheal intubation, IVs, blood drawing, or nasogastric tube) Complications Hypoxia (see Oxygen Desaturation) Hypotension Sepsis Organ failure (eg, hepatic encephalopathy) Pulmonary embolism Drugs Sedatives and other drugs active in the central nervous system, particularly opioids, benzodiazepines, H2 blockers, and antihistamines Withdrawal from alcohol, drugs, or both Intensive care unit (ICU) environment * Sleep deprivation (eg, due to noise, bright lights, or round-the-clock medical interventions) Fear of death Anxiety about unpleasant medical procedures * Particularly a problem for older adults.