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Restoring Coronary Perfusion Pressure before Defibrillation after Chest Compression Interruptions

Coronary perfusion pressure (CPP), also known as simply perfusion pressure, refers to the pressure gradient that drives coronary blood pressure, meaning the difference between the diastolic aortic pressure and the left ventricular end diastolic pressure. Sufficient CPP to provide myocardial reperfusion is required for defibrillation success after prolonged ventricular fibrillation (VF) cardiac arrest. However, when chest compression interruptions occur during cardiopulmonary resuscitation (CPR), there is a precipitous and sustained loss of CPP. The purpose of this study was to quantify the extent to which CPP recovers to pre-pause levels following chest compression interruptions.

This was a secondary analysis of prospectively collected data from two similar IACUC approved protocols. Animal handling and all surgical procedures were in strict compliance with the NIH Guide for the Care and Use of Animals. Both studies were conducted in our USDA-certified laboratory. A total of 105 female Yorkshire swine (weighing 30 - 35 kg) were included. 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). The primary outcome was defined as the ratio of CPP recovery (CPP3- CPP2) to the drop in CPP (CPP1-CPP2).

The results indicated that interrupting chest compressions to analyze the ECG VF rhythm caused a significant drop in CPP from 29.8 mmHg to 6.8 mmHg. Resuming CPR for 20 seconds prior to RS delivery restored 83% (95%CI: 78%, 86%) of the CPP lost during the CPR interruption.


Article by Timothy J. Mader, et al, from Tufts University School of Medicine, Springfield, USA.

Full access: http://mrw.so/4pxQby

Image by Dana Arena, from Flickr-cc.

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