Tuesday, December 20, 2005

New Guidelines continued--Defibrillation

The other major change in the new guidelines is the recommendation for one shock followed by two minutes of CPR before re-evaluation of the rhythm and pulse. That recommendation is strange indeed. It appears to be based on recognition of the problem with current automated-external-defibrillator (AED) algorithms that require long no-compression intervals for rhythm analysis. So why not change the recommendation just for AEDs? I suspect that at least in part the reason is to avoid pointing to a disadvantage of AEDs in comparison to manual defibrillators. If they changed the algorithm just for AEDs, the fact that manual defibrillators don't require such long hands-off periods would be more obvious.

So now we're not supposed to look at the rhythm after a shock until after two minutes of CPR? Does that include shocks given before CPR is started, when the patient quickly regains a perfusing rhythm? The guidelines now seem to be saying this almost never happens, but it is hardly a rare occurrence. This is nutty.

So the one-shock-then-CPR guideline is based on the finding that biphasic defibrillators have a high first-shock success rate. How many hospitals in the US, not to mention the wider world, have biphasic defibrillators? Mine doesn't--at least not in large numbers--and it's not exactly a backwater in the world of health care.

The chapter on electrical therapies shows how truly ga-ga AHA/ILCOR is about AEDs. Most of the chapter concerns AEDs, with a briefer discussion of manual defibrillation toward the end. What's so great about AEDs? There is little doubt that they are useful in certain settings, but for years the AHA has virtually ignored the obvious problem of long mandatory no-compressions intervals in the algorithm. This latest change in the guidelines is a ham-fisted attempt to correct that huge mistake while continuing to gloss over the disadvantages of AED use. Even with the new algorithm, you're waiting ten seconds or more for the device to recognize V-fib--something a minimally-trained human can do almost instantly.

I repeat: this is nutty.

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