ABSTRACT
OBJECTIVES: Tailoring hypothermia duration to ischemia duration may improve outcome from out-of-hospital cardiac arrest. We investigated the association between the hypothermia/ischemia ratio and functional outcome in a secondary analysis of data from the Resuscitation Outcomes Consortium Amiodarone, Lidocaine, or Placebo Study trial. DESIGN: Cohort study of out-of-hospital cardiac arrest patients screened for Resuscitation Outcomes Consortium-Amiodarone, Lidocaine, or Placebo Study. SETTING: Multicenter study across North America. PATIENTS: Adult, nontraumatic, out-of-hospital cardiac arrest patients screened for Resuscitation Outcomes Consortium-Amiodarone, Lidocaine, or Placebo Study who survived to hospital admission and received targeted temperature management between May 2012 and October 2015. INTERVENTIONS: Targeted temperature management in comatose survivors of out-of-hospital cardiac arrest. We defined hypothermia/ischemia ratio as total targeted temperature management time (initiation through rewarming) divided by calculated total ischemia time (approximate time of arrest [9-1-1 call or emergency medical services-witnessed] to return of spontaneous circulation). MEASUREMENTS AND MAIN RESULTS: The primary outcome was hospital survival with good functional status (modified Rankin Score, 0-3) at hospital discharge. We fitted logistic regression models to estimate the association between hypothermia/ischemia ratio and the primary outcome, adjusting for demographics, arrest characteristics, and Resuscitation Outcomes Consortium enrolling site. A total of 3,429 patients were eligible for inclusion, of whom 36.2% were discharged with good functional outcome. Patients had a mean age of 62.0 years (SD, 15.8), with 69.7% male, and 58.0% receiving lay-rescuer cardiopulmonary resuscitation. Median time to return of spontaneous circulation was 21.1 minutes (interquartile range, 16.1-26.9), and median duration of targeted temperature management was 32.9 hours (interquartile range, 23.7-37.8). A total of 2,579 had complete data and were included in adjusted regression analyses. After adjustment for patient characteristics and Resuscitation Outcomes Consortium site, a greater hypothermia/ischemia ratio was associated with increased survival with good functional outcome (odds ratio, 2.01; 95% CI, 1.82-2.23). This relationship, however, appears to be primarily driven by time to return of spontaneous circulation in this patient cohort. CONCLUSIONS: Although a larger hypothermia/ischemia ratio was associated with good functional outcome after out-of-hospital cardiac arrest in this cohort, this association is primarily driven by duration of time to return of spontaneous circulation. Tailoring duration of targeted temperature management based on duration of time to return of spontaneous circulation or patient characteristics requires prospective study.
Subject(s)
Coma/etiology , Coma/therapy , Hypothermia, Induced/methods , Myocardial Ischemia/physiopathology , Out-of-Hospital Cardiac Arrest/complications , Adult , Age Factors , Aged , Aged, 80 and over , Body Temperature , Coma/mortality , Emergency Medical Services , Female , Hospital Mortality/trends , Humans , Hypothermia, Induced/mortality , Male , Middle Aged , Myocardial Ischemia/etiology , North America , Out-of-Hospital Cardiac Arrest/mortality , Out-of-Hospital Cardiac Arrest/therapy , Outcome and Process Assessment, Health Care , Patient Discharge , Prospective Studies , Retrospective Studies , Socioeconomic Factors , Time Factors , Trauma Centers/statistics & numerical dataABSTRACT
STUDY OBJECTIVE: Emergency cardiac care guidelines emphasize treatment of cardiopulmonary arrest with continuous uninterrupted cardiopulmonary resuscitation (CPR) chest compressions. Paramedics in the United States perform endotracheal intubation on nearly all victims of out-of-hospital cardiopulmonary arrest. We quantified the frequency and duration of CPR chest compression interruptions associated with paramedic endotracheal intubation efforts during out-of-hospital cardiopulmonary arrest. METHODS: We studied adult out-of-hospital cardiopulmonary arrest treated by an urban and a rural emergency medical services agency from the Resuscitation Outcomes Consortium during November 2006 to June 2007. Cardiac monitors with compression sensors continuously recorded rescuer CPR chest compressions. A digital audio channel recorded all resuscitation events. We identified CPR interruptions related to endotracheal intubation efforts, including airway suctioning, laryngoscopy, endotracheal tube placement, confirmation and adjustment, securing the tube in place, bag-valve-mask ventilation between intubation attempts, and alternate airway insertion. We identified the number and duration of CPR interruptions associated with endotracheal intubation efforts. RESULTS: We included 100 of 182 out-of-hospital cardiopulmonary arrests in the analysis. The median number of endotracheal intubation-associated CPR interruption was 2 (interquartile range [IQR] 1 to 3; range 1 to 9). The median duration of the first endotracheal intubation-associated CPR interruption was 46.5 seconds (IQR 23.5 to 73 seconds; range 7 to 221 seconds); almost one third exceeded 1 minute. The median total duration of all endotracheal intubation-associated CPR interruptions was 109.5 seconds (IQR 54 to 198 seconds; range 13 to 446 seconds); one fourth exceeded 3 minutes. Endotracheal intubation-associated CPR pauses composed approximately 22.8% (IQR 12.6-36.5%; range 1.0% to 93.4%) of all CPR interruptions. CONCLUSION: In this series, paramedic out-of-hospital endotracheal intubation efforts were associated with multiple and prolonged CPR interruptions.