Effect of Inhaled Xenon on Cardiac Function in Comatose Survivors of Out-of-Hospital Cardiac Arrest—A Substudy of the Xenon in Combination With Hypothermia After Cardiac Arrest Trial

OBJECTIVES: This explorative substudy aimed at determining the effect ofinhaled xenon on left ventricular function by echocardiography in comatose survivorsof out-of-hospital cardiac arrest.DESIGN: A randomized two-group single-blinded phase 2 clinical drug trial.SETTING: A multipurpose ICU in two university hospitals.PATIENTS: Of the 110 randomized comatose survivors after out-of-hospital cardiacarrest with a shockable rhythm in the xenon in combination with hypothermiaafter cardiac arrest trial, 38 patients (24–76 yr old) with complete echocardiographywere included in this study.INTERVENTIONS: Patients were randomized to receive either inhaled xenoncombined with hypothermia (33 C) for 24 hours or hypothermia treatment alone.Echocardiography was performed at hospital admission and 24 4 hours afterhypothermia.MEASUREMENTS AND MAIN RESULTS: Left ventricular ejection fraction,myocardial longitudinal systolic strain, and diastolic function were analyzedblinded to treatment. There were 17 xenon and 21 control patients in whom echocardiographywas completed. Clinical characteristics did not differ significantlybetween the groups. At admission, ejection fraction was similar in xenon and controlpatients (39% 10% vs 38% 11%; p = 0.711) but higher in xenon thancontrol patients after hypothermia (50% 10% vs 42% 10%; p = 0.014).Global longitudinal systolic strain was similar in xenon and control patients atadmission (–9.0% 3.8% vs –8.1% 3.6%; p = 0.555) but better in xenonthan control patients after hypothermia (–14.4.0% 4.0% vs –10.5% 4.0%;p = 0.006). In patients with coronary artery disease, longitudinal strain improved inthe nonischemic myocardial segments in xenon patients. There were no changesin diastolic function between the groups.