Patients and definitions
Initially, we enrolled 32 patients (aged > 18 years) that underwent ECPR at our institute between August 2016 and January 2019. However, two patients were excluded due to failure of return to spontaneous circulation. The demographic and clinical data of the 30 patients were retrospectively collected from our institutional computerized clinical database. This study was approved by the institutional ethics committee/review board of Gil Medical Center (Institutional Review Board No. GAIRB2019-209).
The primary endpoint was successful weaning from ECMO after ECPR. Procedure duration was defined as time between heparin administration and start of ECMO perfusion. Procedure complications included those related to peripheral cannulation and chest compression, such as bleeding, hemothorax, and pneumothorax. ECMO complications included leg ischemia, gastrointestinal bleeding, pulmonary edema, and abrupt ECMO flow disturbance. Loss of pulse pressure was defined as a pulse wave of arterial monitoring that persists less than 15mmHg for over 6 hours within 24 hours after ECPR. Given that no consensus for definition of pulse pressure (pulsatility), we decided pulsatility by referring to “Extracorporeal Life Support: The ELSO Red Book 5th edition” and a previous report.16,17 Arterial monitoring was performed using a radial or brachial artery. Mortality was defined as in-hospital death. Therapeutic hypothermia was induced using Arctic Sun® (Bard Medical, Covington, USA) at a core body temperature target of 33℃ within 6-8 hours after the return of spontaneous circulation (pulse). Core temperature was monitored using a rectal probe and hypothermia maintained for 12-24 hours. Subsequently, rewarming was performed at 0.3℃ per hour to 36.5℃, and then normothermia was maintained at this temperature for three days. Neurologic sequelae were defined as the absence of recovery of cognitive function and neurologic status to those before CPR.