Monopolar cautery: A rare, potential cause of perioperative cardiac arrhythmias.

Sir,

We describe a 30-year old, American Society of Anaesthesiologists Grade-I female who presented with moderate to severe pain right hypochondrium and a solid lesion in segment VI of liver on contrast-enhanced computed tomography abdomen which later proved to be focal nodular hyperplasia on final histopathology. She had intra-operative ventricular fibrillation (VF) during segment VI resection, occurring possibly due to the use of electrocautery during hemostatisis. Her pre-operative biochemistry and haematological tests including liver function tests, serum electrolytes and pre-operative 12 lead electrocardiogram (ECG) were normal. Standard per operative monitoring was employed. Induction and maintenance of anesthesia was done as per standard protocol. Three and half hours later after removal of tumor, sudden VF occurred when the surgeon was performing hemostasis of oozing from the raw surface of liver, with a monopolar cautery in spray mode with energy of 50 W. There was no retractor in place during this step. Surgery was stopped immediately, defibrillation with 200 J was done and rhythm was restored to sinus within 90 sec with a single shock. Surgery was resumed and post event arterial blood gas analysis including serum potassium levels was normal. Rest of the surgical period was uneventful and patient was extubated in the operating room at the end of the surgery. Post-operative 12 lead ECG, two-dimensional echocardiograph, arterial blood gas, serum potassium levels and cardiac markers were all normal. Her post-operative stay in hospital was normal and she was discharged on 5th post-operative day.

Dyselectrolytemia and cardiac disease were ruled out as causes for VF, on the basis of normal potassium levels peri-operatively and no signs of myocardial injury post operatively. The occurrence of intra-operative VF during electrocautery usage and its reversal with a single defibrillating shock suggests that VF was due to an electrical energy resulting from a low frequency leakage of current generated during electrocautery use.

Monopolar mode of cautery can cause leakage of low frequency (50-60 Hz) unwanted currents which are in range with the sensitive frequency for the myocardium (30-110 Hz) and thus have potential to induce arrhythmias.[1] In our case the occurrence of an arc between the diaphragm and tip of electrode when dissecting and controlling bleeding by the coagulation mode probably led to the generation of low frequency leakage current. Owing to the proximity of right ventricle overlying the diaphragm it seems that a far field stimulation lead to the occurrence of this event. Also the inserted central line and saline fluid increased the risk of inducing VF in our patient. The role of an intra-cardiac catheter, pulmonary artery catheter or a central venous catheter as a vector for leakage current has been pointed out earlier.[1]

Fu et al. reported a case of VF during a thoracotomy with electrocautery use and stated the proximity of the surgical site to the cardiac region as the most likely cause of cardiac arrest.[2] Klop et al. have described a case of VF during use of electrocautery in a gastric banding gastroplasty by laparoscopic approach.[3] Perzanowki has reported sudden onset VF during use of unipolar electrocautery near angle of His during a gastric bypass surgery.[4] Yan et al. have reported the occurrence of VF following application of electrocautery to left diaphragm during a laparoscopic subphrenic mass resection and suggested capacitive coupling to be involved in generation of a low frequency current.[1]

This case highlights the possible complication of intra-operative VF with the use of electrocautery during liver resection. Such accidents can be prevented using argon or fibrin glue to control the bleeding from the raw surface of liver. Their limitation though is high cost. In our experience of more than 150 cases of liver resections in last 8 years this is the first such event. Since then we are using electrocautery at a much lower energy, i.e., 20 W as a preventive measure.

Strict vigilance, continuous alert monitoring and availability of advanced resuscitation equipments should be ensured during liver resections.