Doctor finds defibrillator statistics questionable
|From Ocean Navigator #104 |
As a cardiologist and ocean-sailing cruiser, I was pretty surprised at the January/February Chartroom Chatter sidebar touting automatic defibrillators aboard sailboats. Mostly, I was astounded by the 90% (or 98%) survival rate claimed by the would-be purveyors of this equipment. By way of contrast, a large multi-center study reported in the March 1999 American Journal of Cardiology described a survival rate of 50% after one month in patients whose defibrillation was performed immediately after observed arrest.
No question, defibrillation is usually effective in restoring normal heart rhythm, if used promptlyat least, for a time. This does not, however, equate with survival. If (as is commonly true) the cause of the arrest was obstruction of a coronary artery (heart attack), then there is a substantial likelihood of ongoing cardiac damage, despite restoration of normal rhythm, and the mortality risk remains high. Optimal management of this situation requires admission to a technically sophisticated coronary care unit, or intensive care unit. Unfortunately, as cited above, this is no guarantee of success, either.
I can think of few less favorable venues for treatment of a heart attack than a sailboat at sea, with no recourse to rapid transfer ashore of a critically ill patient. This is not a situation where an ambulance can quickly reach a defibrillated survivor at a mall, or at an airport following in-air resuscitation: the delay of effective hospitalization is measured in days, not minutes, making true long-term survival even less likely than that cited above. Prevention, not expensive high-tech arrhythmia management, seems more appropriate for this milieu. Given the choice between the defibrillator, and a small dose of aspirin daily (assuming no aspirin intolerance), I would surely elect the latter.