This question is perennial and without consistent response.
I am an EP attending who is within a few years of fellowship.
I few points:
1.) The ASA, HR Society and device manufacturers all recommendations and none of them agree.
2.) the danger of electrocautery is twofold: A) detection leading to innapropriate ICD therapy. b) detection leading to inhibition of ventricular pacing in someone who is pacer dependant.
2.) The type of electrosurgery (cautery) being used is relevant. If it is bipolar, then there is really very little chance of either of the above occuring (you would need to be essentially right at the right ventricular lead tip. If it is unipolar (the more common type) then a good rule of thumb is that if you are six inches away from the RV lead tip (which is where the EMI would be detected by he device) you are probably ok and there is little chance of detecting electrocautery. This cataract surgery, extremity surgery, abdominal surgery (unless at the diaphragm level) etc would have really very very low chance of being near the RV lead tip.
3.) All modern pacemakers have noise detection algorithms which briefly switch pacing modes to VOO and thus eliminate chances of inhibition of ventricular pacing.
4.) Placing a magnent on an ICD will temporarily disable tachycardia detection (and permanently do so in a few older Guidant devices of which there are very few around still in breathing patients). Thus as soon as the magnet has been removed, the ICD is immediately "on." Placing a magnet on any ICD does NOTHING to the pacing mode of the ICD. To change the pacing mode of an ICD you need a programmer. In
5.) Placing a magnet on a PPM changes the pacing mode to asynchronous only for the duration that the magnet is on the PPM. (understand that when you say "pacemaker" you are really saying "this is not an ICD" { all ICDs are also capable of pacing }).
6.) The major device companies recommend that magnets be placed on ICDs to "turn them off for surgery" because the chance of sending the patient home with a magnet taped to their chest is low. This is in contrast to the risk of a patient being sent home with their ICD programmed "off." accidentally. This really does happen, I have seen it.
7.) To take the point of number six a little further, when you the physician call and ask that a company rep come and turn off a device, YOU are writing an order medico-legally speaking. The device rep documents your name in the chart. If that patient goes home with the ICD programmed off (because you forgot to ask the company rep to come back and program it back on { or for any other reason } you the physician are medico-legally responsible. This is regardless of whether you are a surgeon, anesthesiologist or if really know what you are doing or not. Each time you call the rep, you are legally responsible for what he or she does with the device. They cannot alter programming without a physicians order. This has been tested in the courts. The magnet method is safer.
Here is one method of dealing with this issue on the whole:
THIS IS NOT MEDICAL ADVICE.
Where on the body are you doing surgery? If you are more than six inches from the heart, do not touch the device.
If you are within six inches of the device in the chest or upper abdomen, then
1) Find out if the patient is pacemaker dependent.
2) Find out if the device is an ICD.
3) Find out who made the device (ie Medtronic, St. Jude, etc)
If they are pacemaker dependent, use a programmer to change the pacing mode to asynchronous. A magnet taped over the device is likely to be in the way of the sterile field. Realize that if it is a pacemaker, even this you probably don't need to do because pacemakers have EMI noise reversion modes that are designed to do this for you when they see EMI from cautery. Also realize that even if this fails, a couple (2 or 3) of seconds of asystole never hurt anyone (how long is the surgeon really using the bovie un-interrupted?!?).
If the device is an ICD you will want to turn off the ICD function (called "tachycardia detection") with a programmer (again a magnet will be in the surgical field.) Don't forget to turn it back on however.
_____________
one last thing... It makes all the sense in the world to me that anesthesiologists would take this bull by the horns and take ownership of this issue. They are perioperative medicine experts and it is clear to me that the most efficient means of handling these issues is for them to do it themselves (much has been the case with intraoperative TEE). Yes this would require some education but it really isnt all that complicated (much less so than intraoperative TEE).
