Therapeutic Hypothermia Following Emergent Coronary Artery Bypass Grafting After Failed Percutaneous Coronary Intervention in a Comatose Post-Cardiac Arrest Patient
A 60-yr-old female without a significant past medical history presented to the emergency department (ED) with cardiac arrest on March 14, 2012. A security guard found her at her apartment and called for the emergency medical services (EMS). EMS personnel transported her to the ED without patient monitoring or basic life support for 10 min. She had collapsed 25 min before ED arrival and was in asystole. Return of spontaneous circulation (ROSC) was achieved after 14 min of advanced life support, including the application of 3 shocks, orotracheal intubation, and the administration of 4 mg adrenaline and 300 mg amiodarone. Her initial blood pressure was 68/49 mmHg, her pulse was 90 beats per minute, and her tympanic temperature was 36℃. The patient was comatose (Glasgow coma scale score E1VTM2=4) with a pupillary light reflex and self-respiration. The initial electrocardiogram showed atrial fibrillation with ST-segment elevation in leads V5-6, II, III, and aVF, indicating STEMI (). A blood gas analysis was significant for severe acidosis (pH 6.97; lactate 6.1 mM/L; BE -10.8). A 2D-echocardiogram performed by a cardiologist in the ED revealed moderate left ventricle systolic dysfunction, an ejection fraction of 30%-40% and akinesis of the basal-apical inferolateral wall and lateral wall. At 55 min after ROSC, she underwent PCI, which failed because the guide wire could not pass the lesion of completely occluded left proximal circumflex artery (LCx) due to extreme angulation. She also had 70% diffuse stenosis of the proximal and middle left anterior descending coronary artery on coronary angiogram. An intra-aortic balloon pump was applied because of her unstable vital signs, and she was transferred to the operating room for an emergent CABG at approximately 4 hr after ROSC. A hard segment in the proximal area of the LCx was observed in the heart, and the aortocoronary saphenous vein graft (SVG) was anastomosed to the second obtuse marginal branch of the LCx. The CABG was finished in 6 hr 20 min. She was brought to the intensive care unit (ICU) at 10 hr 25 min after ROSC. On arrival in the ICU her rectal temperature was 34.6℃. For cerebral protection, TH was initiated using an endovascular cooling system (Alsius Corp., Irvine, CA) with sedative and neuromuscular blocker infusion despite the risk of hypothermia-induced coagulation abnormalities after CABG. At 2 hr after TH initiation, her body temperature reached the target rectal temperature of 34℃, which was maintained for 12 hr. The patient was actively rewarmed to 36.5℃ at a rate of 0.25℃/hr (). During the maintenance of TH, her 12-hr postoperative blood loss was approximately 1,060 mL, and blood products, including 4 U of fresh-frozen plasma, 1 U of packed red blood cells and 1 U of single-donor platelets, were required to stabilise the patient. During TH, several coagulation parameters were altered, including prothrombin time (PT, 15.3-50.6 sec; reference range, 10-14 sec), international normalised ratio (INR, 1.36-4.23; reference range, 0.85-1.5), and activated partial thromboplastin time (aPPT, 46.2->120 sec; reference range, 23-35 sec). No complications were associated with hypothermia, except for coagulation abnormalities. On day 2, amplitude-integrated electroencephalography showed continuous normal voltage, and somatosensory-evoked potential showed bilateral N20 peaks. The patient regained consciousness at 36 hr after ROSC and was successfully extubated on day 5. Her mental state continued to show improvement to baseline despite a minor calculation disorder. She suffered pneumonia and pancreatitis during her stay in the ward and was discharged home with a cerebral performance category scale (CPC) score of 1 six weeks later.