CARING FOR THE CRITICALLY ILL PATIENT Association Between Arterial Hyperoxia Following Resuscitation From Cardiac Arrest and In-Hospital Mortality

SUDDEN CARDIAC ARREST IS THE most common lethal consequence of cardiovascular disease. Even if return of spontaneous circulation (ROSC) from cardiac arrest is achieved, approximately 60% of patients will not survive to hospital discharge. The high mortality is attributed to the postcardiac arrest syndrome, which involves global ischemiareperfusion injury, myocardial stunning, and anoxic brain injury. The recent success of therapeutic hypothermia for post-ROSC neuroprotection has increased momentum for investigating post-ROSC factors that can improve outcomes. In the search for modifiable postROSC factors, the role of supplemental oxygen, which is often administered in high concentrations to patients after cardiac arrest has come into controversy. There is a paradox with oxygen when delivered to the injured brain. Too little oxygen may potentiate anoxic injury. Too much oxygen may increase oxygen free radical production, possibly triggering cellular injury and