Eye injury
Eye injury
When operating in the periorbital area, patients should wear nonmetallic corneal shields, since sparks may arc toward the globe causing corneal damage and scarring. The corneal shields must be plastic rather than metal to prevent conducting the current toward the globe.32
Cardiac pacemaker, defibrillator, or deep-brain stimulator malfunction
Electrosurgery has the potential to interfere with cardiac pacemaker, implantable cardioverter–defibrillator (ICD), or deep-brain stimulator function. Pacemakers are generally classified as fixed rate or demand type. Fixed-rate pacemakers fire at a predetermined rate irrespective of the intrinsic cardiac rhythm. Demand-type pacemakers fire at a predetermined rate only in the absence of intrinsic cardiac rhythm.
Demand-type pacemakers are further subdivided into ventricular inhibited or ventricular triggered. The ventricular-inhibited, demand-type pacemaker is the most common pacemaker in the United States.
Since fixed-rate pacemakers fire at a fixed rate regardless of intrinsic cardiac rhythm, they lack sensing circuitry. Consequently, exogenous electrical signals from the active electrode pose no threat to the patient. Conversely, all demand pacemakers contain sensing circuitry and are therefore susceptible to interference from extraneous electrical current. The function of demand pacemakers is to prevent bradycardia and asystole. The ventricular-inhibited pacemakers do this by firing when the patient’s intrinsic cardiac rhythm is slower than the preset rate. A ventricular-triggered device fires with each spontaneous heartbeat as well as at a predetermined rate in the absence of intrinsic rhythm.28,33
The electromagnetic output of electrosurgery can interfere with the sensing circuitry of demand pacemakers causing them to erroneously perceive the electrical current from electrosurgery as spontaneous ventricular contraction. In the setting of a ventricularinhibited pacemaker, the pacemaker perceives this electrical current as a spontaneous heartbeat and erroneously enters stand-by mode. This can cause bradycardia and asystole leading to syncope, seizure, or death. In a ventricular-triggered device, the electrical current is misread as a spontaneous heartbeat causing the pacer to falsely stimulate ventricular contraction. This can cause life-threatening tachyarrhythmias or ventricular fibrillation. Although any electrosurgical procedure poses a risk for pacemaker-related complications, electrosection poses the highest risk.31,33
An ICD is a device that sends a defibrillatory shock to the heart if it senses tachyarrhythmia or ventricular fibrillation. It is usually inserted into an abdominal or infraclavicular subcutaneous pocket. Electrosurgery can cause an ICD to erroneously shock the heart, which is not only excruciatingly painful to an alert patient but can induce life-threatening tachyarrhythmias. Electrosurgery can also damage the ICD device itself.31
A deep-brain stimulator is an implanted device that generates electrical impulses to control movement disorders such as essential tremor or Parkinson’s disease. An electrode implanted in the brain is connected to a pulse generator that sits in a subcutaneous pocket in the chest, much like an ICD. As with an ICD, electrosurgery can interfere with functioning of the brain stimulator.
Electrosurgery in the setting of pacemakers, ICDs, or deep-brain stimulators poses life-threatening complications, but how common are they? A survey study of 166 Mohs surgeons with a total of 1959 years of experience examined the number and type of complications due to electrosurgery. The incidence of interference was exquisitely low with 1.6 cases/100 years of surgical practice. The incidence of clinical adverse events was even lower at 0.8 cases/100 years of surgical experience. There was no significant
morbidity or mortality. The 25 cases of interference were broken down as such: 8 patients experienced skipped beats, 6 patients had spontaneous reprogramming of their pacemaker, 4 patients had their ICD fire, 1 patient had a shortening of his pacer’s battery life, and 1 patient experienced tachyarrhythmia. Of these 25 cases, 18 of the patients experienced a clinical adverse outcome: 6 had syncope, 5 had altered sensorium, 3 experienced palpitations, 3 required an outpatient cardiology consult, and 1 experienced hemodynamic instability.29 There are only two reports of deep-brain stimulator interference.34
Despite this data, several groups, including the American Society of Anesthesiologists, recommend that the patient’s cardiologist be consulted prior to using monoterminal electrosurgery, and that devices be interrogated within a month after any monoterminal electrosurgical procedure, though the degree to which these suggestions are followed is unknown.35
Still, the use of electrosurgery in patients with implanted devices is very safe. This is in part due to the fact that modern-day pacemakers are designed with metallic covers and filters to protect the device from external electrical interference, and therefore minimize the risk of malfunction. However, precautions should still be taken. Place the grounding electrode at a site far from the heart and pacemaker and try to avoid having the heart lie directly in the path between the treatment and indifferent electrode. Keep electrosurgical current bursts to less than 5 seconds. If operating near a pacemaker or ICD, utilizing electrocautery or biterminal forceps will avoid or minimize current leakage in the patient. Similar precautions should be taken with patients who have cochlear implants.