Analysing 837 rhythms from 135 consecutive patients, the investigators compared AED recommendations against physician interpretation. Importantly, the AED concluded that:
- 16% of deemed shockable rhythms were not shockable (and therefore not treated)
This was due to artefact, fine VF, error or a combination of factors, and the subsequent omission or delay of defibrillation was thought to be clinically relevant in 6 cases.
- 4% of non-shockable rhythms were shockable (and therefore treatment recommended)
This was again due to artefact, and in one case an internal defibrillator firing. These recommendations resulted in 15 spurious shocks, although no deleterious consequences resulted
To me this reinforces the fact that, as health professionals, we should be doing the rhythm interpretation and not blindly following an AED. This a substantial error rate that may, in shockable rhythms especially, lead to poorer outcomes.
So, in places with an AED on the resus trolley, it is important to know how to override the machine and push it into a manual mode (for those that display the rhythm and allow this, at least) so the clinician can control the machine, not vice versa. The process for doing this is different for each manufacturer/model. It tends to be fairly simple, so if you're in this circumstance, it may be worthwhile working out if you can drive your AED.
In the absence of a clinician able to interpret the rhythm, however, using an AED in combination with good quality CPR, and following its recommendations will still save more lives than not using one.