Successful resuscitation of cardiac arrest caused by CO2 embolism with intra-aortic injection of epinephrine during off-pump coronary bypass surgery -a case report-
A 72-year-old male patient with acute coronary syndrome underwent OPCAB. He had a left ventricular ejection fraction of 42% and regional wall motion abnormalities compatible with multi-vessel territories. The patient was in normal sinus rhythm. Coronary angiography findings revealed total occlusion at the proximal left anterior descending artery (LAD), 50-75% stenosis at the mid to distal left circumflex artery, and 90% stenosis at the mid right coronary artery (RCA).\nCardiac surgery was performed through a median sternotomy, and the heart was displaced using a deep pericardial retraction suture, gauze swab, and tissue stabilizer. After confirming the lack of atheroma burden in the ascending aorta by epiaortic ultrasound examination, the left radial artery was connected to the ascending aorta. After completing the LAD grafting using the left internal thoracic artery, grafting was performed on the obtuse marginalis (OM) branch. The patient was in the Trendelenburg position, and norepinephrine was infused at a dose of 0.15 µg/kg/min. After stabilizer application, there was a temporary deterioration in the patient's hemodynamic status, which was stabilized without the aid of incremental doses of norepinephrine dosage.\nAfter opening the anastomotic site at the OM branch, the surgeon informed us the patient was bleeding from the arteriotomy site despite placement of a proximal snare. The CO2 blower was more aggressively used to aid grafting at a flow rate of 3-5 L/min. Bleeding was replaced by colloid solution, and all hemodynamic variables were stable: systemic blood pressure 121/58 mmHg, heart rate 59 beats/min, pulmonary arterial pressure 24/11 mmHg, cardiac index 2.6 L/min/m2 and mixed venous oxygen saturation 82%. Approximately 5 minutes after the commencement of grafting, the surgeon decided to insert an intracoronary shunt for better visualization. Suddenly, the patient's systemic blood pressure decreased to 64/56 mmHg despite increasing the norepinephrine dose from 0.05 µg/kg/min to 0.30 µg/kg/min. The pulmonary arterial pressure increased to 34/20 mmHg, and the mixed venous oxygen saturation decreased to 66%. Vasopressin 0.6 IU was quickly administered intravenously, and the transesophageal echocardiography (TEE) revealed a massive gas floating at the orifice of the RCA (). On the TEE, no gas was visible in the right heart without any patent foramen ovale. Although the patient remained in normal sinus rhythm, complete heart block occurred within minutes, and ventricular pacing was commenced. Over the next several minutes, ventricular fibrillation developed; despite aggressive treatment, including defibrillation, epinephrine, and direct manual cardiac massage, adequate circulation could not be restored, and cardiac massage was continued. Upon preparing for emergent conversion to cardiopulmonary bypass (CPB), epinephrine 300 µg was injected directly to the aortic root by the surgeon using a 26-gauge needle. Subsequently, manual cardiac massage was continued for several cycles, and spontaneous recovery of unspecified cardiac rhythm was observed. Then the patient's systemic mean arterial pressure gradually rose from 38 to 103 mmHg, and recovery of normal sinus rhythm and contractile performance followed immediately. Other hemodynamic parameters, including pulmonary arterial pressure, also returned to normal levels. The remaining grafts were performed successfully without conversion to CPB, and no sign of bleeding was observed at the puncture site in the aorta. The patient had an unremarkable postoperative course without neurologic deficits and was discharged 10 days after the surgery.