Management of Patients With Cardiovascular Implantable Electronic Devices in Dental, Oral, and Maxillofacial Surgery

The article that I'd like to review is called, The Management of Patients with Cardiovascular Implantable Electronic Devices, or CIEDs, in Dental and Oral Maxillofacial Surgery. This is from the Journal of Anesthesia Progress, volume three, 2016, pages 95 to 103. The name of the authors is James Tom. In 2012, approximately three million patients have these types of advices implanted. 250,000, or a quarter of a million, are placed each year. Concerns for dental professional include electronic magnetic interferences, or EMI, from electrosurge, electrocautery devices, APEX locators, lasers, electrical hand pieces, radiation, and from magnets in bibs, bib clips, headrests, etc. Number two, vasoactive drugs such as epinephrine. Pacemakers, these are generally for symptomatic bradycardias. There are two main parts. There's a pulse generator and then an insulated wire that has cardiac leads that implants into the myocardium. It is implanted into the left pectoralis muscle usually and a magnet reed valve controls pacemakers with the use of a magnet. Lithium batteries last for approximately 10 years in these and need to be replaced. 

The classical concern with pacemakers is to prevent rhythm disturbances with electrosurge and cautery units and a magnet is placed near the pacemaker to enable an asynchronous mode or pacing mode. In other words not synchronizing the patient. There can be problems though with restoring synchrony or with the patient having arrhythmias with this intervention, with the placement of a magnet. There are implantable cardioverter defibrillator, or ICDs, and these are for unstable tackarrhythmias, ventricular tachycardia, etc. they can cardiovert or they can defibrillate the patient. They have similar components to pacemakers and a magnet will also suspend shocks. If a person has more than three shocks in 24 hours, termed repeated shocks, they are associated with what's called an electric storm and have a high mortality rate.

Your preoperative evaluation for this patient is to get an idea of what their activity tolerance is and therefore they're metabolic equivalence. They also recommend that you get a device interrogation within 30 days of the procedure, meaning the cardiac team interrogates the device to see what kind of events have occurred and gives us a report of those events. If you're doing moderate sedation to general anesthesia, you're encouraged to get a 12 lead EKG and to consult with the cardiac team, especially when it's a prolonged procedure or if you're using vasal active medications. These patients by definition are typically ASA3 or ASA4 patients.

Now the American Society of Anesthesiology and the Heart Rhythm Society recommend "having a magnet immediately available." Now I can tell you I do not have a magnet immediately available in my clinic but I suppose by dialing 911 that may be considered immediately available. For paraoperative management your primary concern is with EMI or electromagnetic interference. Different issues and things to look from our electrosurge. Electrosurge was discussed and of course monopolar is considered low risk of interfering with either of those two implantable devices. ICDs, bipolar of course is better and make sure you put the grounding pads away from the ICD.

Number two, electronic and piezoelectric dental scalars, APEX locators, light curing units, and other common dental instruments all emit a low EMI, but there have been no documented cases of issues and therefore the concern is minimal. Laser surgery, so theoretically it's possible, no cases or problems have ever been reported in literature, and the threat is minimal and so there is little concern. Radiation, 2.5% of pacemakers and 6.8% of ICDs fail when under direct radiation therapy for oncological reasons. Keep in mind this is not diagnostic imaging, and the same dose with diagnostic imaging, it is with actual therapeutic radiation for cancer treatment. The article suggests contacting the cardiac team before using diagnostic radiation. I personally think this is kind of ludicrous. I am not going to do that. The amount of radiation that is actually absorbed and given during sten or dental x-rays is minuscule in comparison and in fact they acknowledge that the amount in orders of magnitude less than therapeutic radiation. 

For instance, a lateral sef is approximately 125 microsebers or .000125 microsebers and head and neck oncology patients received between six to 10 gray instead of .000125 gray. This is on an order of 10,000 to 100,000 times difference and keep in mind that the six to 10 gray only causes problems in 2.5 to 6.8% of the time, so roughly 7% or less of the time. Now an MRI is contraindicated in these patients, unless of course the device is compatible. Of course, the suggestion is to use shielding and we use shielding anyways with our patients for all sorts of reasons. Anesthesia and medications. You want to be cautious with sympathomimetics, such as epinephrine. General guidelines include, number one, avoid hyperventilation. Number two, avoid hypovolemia. Number three, avoid acid base shifts. Number four, watch out for intervascular overloading. Number five, large volume blood transfusions should be avoided.

Just as a side note, I always find this interesting because when does anyone try not to avoid a large volume blood transfusion or any of these things as far as that goes, but I think it's important from an academic perspective to go through these things so that you know what to watch out for. Also be cautious with beta blockers and anticholinergics. Biz monitoring does not interfere with IEDs or ICDs but ICDs can interfere with biz monitoring, which is interesting. Watch out for magnet big clips. Be cautious with these. In fact just avoid them because you'd hate to have a magnet that's powerful enough to effect the actual implantable device and to make it asynchronous. Yikes. The iPad 2 has triggered magnet modes and so that should not be placed directly over the device as well. Watch out for magnet headsets or cushions or headrests. Essentially anything magnet that could go near there. 

Resuscitation, possible but a small, yet still insignificant risk to rescuers. Basically what that means is that if someone's getting defibrillated or shocked internally from their ICD, you can get a small shock if you're the one doing chest compressions but it won't hurt you. ACLS is still used along with all the drugs, all the interventions, including cardioversion and transcutaneous pacing.

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