Therapeutic Hypothermia After Perioperative Cardiac Arrest in Cardiac Surgical Patients

Background. Therapeutic hypothermia (TH) has been established as an effective treatment for preserving neurological function after out-of-hospital cardiac arrest (CA). Use of TH has been limited in cardiac surgery patients in particular because of concern about adverse effects such as hemorrhage and dysrhythmia. Little published data describe efficacy or safety of TH in cardiac surgical patients who suffer unintentional CA. However, the benefits of TH are such as may suggest clinical equipoise, even in this high-risk patient population. Objective. To report a series of 3 patients in our institution's cardiac surgery ICU who suffered unintentional CA within 48 hours of cardiac surgery and were treated with TH. Methods. After institutional review board approval, study patients were identified by diagnosis of undesired intraoperative CA or arrest on ICU days 1 to 2, as well as having documented TH. The institution's electronic medical record and the Society of Thoracic Surgeons database were retrospectively reviewed for demographic information, comorbid diagnoses, surgical procedure, and outcomes, including hemorrhage, rewarming dysrhythmias, infection, in-hospital mortality, and neurologic outcome were assessed. TH was initiated and monitored using active cooling pads according to written institutional protocol. Results. Four patients received TH after perioperative arrest. One patient was inadequately cooled and had massive surgical bleeding, and was therefore excluded from this review. The remaining 3 patients had a predicted mortality of 14.6% (±13.3) based on Euroscore calculation and were cooled for 17.6 ± 4.0 hours after CA. Coagulopathy, hypovolemia, severe electrolyte abnormalities, and rewarming dysrhythmias were not identified in any patient. Two patients were discharged home and one was discharged to a long-term care facility. Conclusion. Herein we report the safe and successful use of TH after unintentional perioperative CA in 3 cardiac surgery patients. These data suggest that further investigation of this therapy may be warranted given the potential benefit and apparent safety in a small series.