66 - Compression Fraction Alone Does Not Adequately Measure Cardiopulmonary Resuscitation Quality in Out-of-Hospital Cardiac Arrest
Thursday, May 14, 2020
8:12 AM – 8:24 AM
Location: Vail: Majestic Level
Participants should be aware of the following financial/non-financial relationships:
Angelica Loza-Gomez: No financial relationships or conflicts of interest
Megan Johnson: No disclosure data submitted.
Lawrence H. Brown, PhD: No financial relationships or conflicts of interest
Marianne Newby: No disclosure data submitted.
Todd leGassick: No disclosure data submitted.
Baxter Larmon: No disclosure data submitted.
Angelica Loza: No disclosure data submitted.
Background and Objectives: High quality CPR with minimal interruptions maximizes survival with good neurological outcome in out-of-hospital cardiac arrest (OOHCA). Current efforts to maximize CPR quality focus on compression fraction (CF), defined as the percentage of time chest compressions are performed during the OOHCA case duration. CF does not account for "compressions in target" (CiT); that is, the proportion of compressions at the recommended rate (100-120/min) and depth (2.0-2.4 inches). The purpose of this study was to evaluate whether CF correlates with CiT in OOHCA. Our null hypotheses were (1) there would be no linear correlation between CiT and CF, and (2) CiT would not differ for events with high (≥60%) and low (<60%) CF.
Methods: This prospective observational study included adult non-traumatic OOHCA cases attended by three EMS agencies in Los Angeles County, California between January 1 and September 30, 2019. All OOHCA cases recorded by the EMS agencies were eligible. Exclusion criteria were pregnancy, prisoners, CPR time less than 3 minutes, and weight less than 90 lbs. CF, CiT, depth and rate were automatically recorded by the monitor/defibrillator. CiT and CF are reported as median and IQR. Correlation between CiT and CF was evaluated using Spearman's rank correlation; CiT among cases with high and low CF was compared using Wilcoxon Rank Sum test. An a priori power calculation indicated a sample size of 85 cases would provide 80% power to detect a moderate (r = 0.30) linear association between CiT and CF.
Results: A total of 120 patients met inclusion criteria. The median age was 72.5 years (IQR 61-82); 55 (45.8%) were witnessed arrests; 51 (42.5%) received citizen CPR, and 46 (38.3%) achieved ROSC. Median CF was 83% (IQR 72%-90%) and median CiT was 13% (5%-29%). There was no significant correlation between CiT and CF (Spearman’s Rho = 0.165, p=0.072); CiT also did not differ among cases with high CF (CiT = 13%, IQR 4%-29%) and low CF (CiT = 11%, IQR 5%-27%).
Conclusion: In this study, CF was high at 83%, but CiT was low at 13%. There was no correlation between CiT and CF, whether measured linearly or when dichotomizing CF as higher or lower than 60%. These results question the current focus on CF as the sole metric of CPR quality. Future larger prospective studies are needed to explore CiT as an additional or alternative measure of CPR quality.