Ice Ice Baby! A Decade of Therapeutic Hypothermia
For as long as I can remember, the American Heart Association (AHA) has promoted a concept of "4 links" in the chain of survival when a patient suffers a cardiac arrest: early access (to prehospital care), early CPR, early defibrillation, and advanced cardiac life support. During the past decade, however, the utility of advanced cardiac life support has been questioned in favor of basic life support, and the benefits of early cardio-pulmonary resuscitation has also been questioned in favor of simple chest compressions only. Fortunately, as 2 of the links were coming unraveled, a new "missing link" was being discovered. Post-arrest care (PAC) has become the "fifth link" in the chain of survival, and the most celebrated aspect of PAC has been therapeutic hypothermia (TH).
In 2002, The New England Journal of Medicine published 2 randomized studies that brought TH to the forefront of cardiac arrest care. Patients who suffered cardiac arrest associated with ventricular fibrillation or pulseless ventricular tachycardia (VF/VT) and had return of spontaneous circulation (ROSC) were cooled to 32°C-34°C for 12-24 hours. Marked improvements in outcome were noted: The number of patients needed to treat (NNT) to allow 1 additional patient to survive was 7, and the NNT to improve neurologic outcome was 5. Numerous subsequent observational studies supported the benefits of TH, and it was endorsed as the first therapy in cardiac arrest victims since defibrillation to be both life-saving and neurologic-sparing.
Two recent articles from the cardiology literature have summarized the past decade in TH advances and the current state of knowledge on this topic. I recommend all emergency care providers read the full articles, but I'll summarize some of the key points.
Introduction
For as long as I can remember, the American Heart Association (AHA) has promoted a concept of "4 links" in the chain of survival when a patient suffers a cardiac arrest: early access (to prehospital care), early CPR, early defibrillation, and advanced cardiac life support. During the past decade, however, the utility of advanced cardiac life support has been questioned in favor of basic life support, and the benefits of early cardio-pulmonary resuscitation has also been questioned in favor of simple chest compressions only. Fortunately, as 2 of the links were coming unraveled, a new "missing link" was being discovered. Post-arrest care (PAC) has become the "fifth link" in the chain of survival, and the most celebrated aspect of PAC has been therapeutic hypothermia (TH).
In 2002, The New England Journal of Medicine published 2 randomized studies that brought TH to the forefront of cardiac arrest care. Patients who suffered cardiac arrest associated with ventricular fibrillation or pulseless ventricular tachycardia (VF/VT) and had return of spontaneous circulation (ROSC) were cooled to 32°C-34°C for 12-24 hours. Marked improvements in outcome were noted: The number of patients needed to treat (NNT) to allow 1 additional patient to survive was 7, and the NNT to improve neurologic outcome was 5. Numerous subsequent observational studies supported the benefits of TH, and it was endorsed as the first therapy in cardiac arrest victims since defibrillation to be both life-saving and neurologic-sparing.
Two recent articles from the cardiology literature have summarized the past decade in TH advances and the current state of knowledge on this topic. I recommend all emergency care providers read the full articles, but I'll summarize some of the key points.