Abstract 13966: Left-sided Rib Fractures During Cardiopulmonary Resuscitation Are Associated With Better Coronary Perfusion Pressure in a Pig Model of Cardiac Arrest

Abstract

Introduction: Since its inception, concerns have been raised about the complications associated with cardiopulmonary resuscitation (CPR). To date, there is no evidence that these complications are linked to worsened outcomes. Hypothesis: The aim of this study was to describe the hemodynamic effect of rib fractures during automated mechanical CPR in a porcine model of cardiac arrest. Methods: We conducted a prospective observational study between November 2013 and November 2014. Animals were included if they developed rib fractures during CPR but prior to injection of any drugs. To determine the exact timing of the broken rib, only pigs with obvious thorax deformation were included. An autopsy was performed at the end of each study. A group of 11 control animals without broken ribs was also included to compare data between groups. Time points in the control group matched those in the broken rib group. Data are presented as mean ± standard error of mean. Results: Broken ribs were observed during CPR in 15 pigs at a mean time of 97 ± 10 sec after the start of CPR (12 with left chest deformation and 3 with right chest). The mean number of broken ribs was 4 ± 0.2. In the left-sided broken rib group, coronary perfusion pressure (CPP) and systolic blood pressure (SBP) increased after rib fractures (p for trend <0.001). EtCO2 increased similarly in the left broken rib group from 31 ± 5 prior to rib fracture to 43 ± 3, 46 ± 4 and 49 ± 4 at 10, 30 and 60 seconds after rib fracture, respectively (p for trend <0.001). This increase was not observed in the right-sided broken rib group (Fig 1). Return of spontaneous circulation was achieved in 12/12 animals with left broken ribs, 1/3 animals with right broken ribs and 6/11 animals in the control group (p=0.007). Conclusion: During CPR, left rib fractures improved CPP, SBP and EtCO2 compared to control animals. This may suggest direct cardiac compression as a means to the effect. Further studies are warranted to assess the impact on survival.