Restoring Coronary Perfusion Pressure before Defibrillation after Chest Compression Interruptions

Background: Sufficient coronary perfusion pressure (CPP) to provide myocardial reperfusion is required for defibrillation success after prolonged ventricular fibrillation (VF) cardiac arrest. Chest compression interruptions cause a precipitous drop in CPP. Objective: To quantify the ex- tent to which CPP recovers to pre-pause levels following chest compression interruptions. Me- thods: This was a secondary analysis of data from two similar IACUC approved protocols. A total of 105 Yorkshire swine were included and VF was electrically induced. After 10 minutes of untreated VF in the first study (n = 52) and 12 minutes of untreated VF in the second (n = 53), CPR began and epinephrine was administered approximately 2 minutes prior to a planned 10-second pause to record an artifact-free ECG waveform segment. Following this pause, CPR was resumed for 20- seconds prior to defibrillation. CPP data were extracted from three time points: 2 minutes after epinephrine delivery (CPP1); following the chest compression pause (CPP2); and immediately before defibrillation (CPP3). Our primary outcome was defined as the ratio of CPP recovery (CPP3- CPP2) to the drop in CPP (CPP1-CPP2). Results: Interrupting compressions resulted in a significant drop in CPP (29.8 mmHg [95%CI: 26.2, 33.4] to 6.8 mmHg [95%CI: 5.4, 8.2]). Resuming CPR for restored 83% (95%CI: 78%, 86%) of the CPP lost. Conclusion: This study demonstrates that 83% of the decline in CPP values during a planned 10-second interruption in CPR can be restored with a short period of precordial compressions prior to defibrillation.