Effects of manual high-impulse CPR on myocardial perfusion during cardiac arrest in pigs

The aim of the study was to compare the effect of a 30 and 50% duty cycle on coronary perfusion pressure (CPP) and end tidal carbon dioxide (ETCO2) and to determine whether a duty cycle of 30% can be achieved manually. After 3 min of ventricular fibrillation cardiac arrest, pigs were resuscitated in two groups with changing duty cycles every 3 min: group A starting with 50 and then 30%; and group B starting with 30 and then 50%. After administration of epinephrine, duty cycles in group A were 50 and then 30%, in group B initially 30% and then 50% Before administration of epinephrine, no significant differences in CPP between the 30 and 50% duty cycles were found; after epinephrine CPP increased with both duty cycles. ETCO2 did not vary before epinephrine; after epinephrine, there were statistically significant differences but there is doubt regarding the clinical relevance of these differences. Survival was 4/6 in group A and 3/5 in group B (NS). It is possible to perform a manual duty cycle of 30%. However, our data do not support the use of a 30% duty cycle during cardiopulmonary resuscitation (CPR).