EFFECT OF VEST CARDIOPULMONARY-RESUSCITATION ON CEREBRAL AND CORONARYPERFUSION IN AN INFANT PORCINE MODEL

Objectives: To determine cerebral and myocardial blood now rates durin g vest cardiopulmonary resuscitation (CPR) without direct cardiac comp ression in an infant porcine model. Also, to determine if circumferent ial chest compression without the chest deformity ordinarily associate d with precordial compression maintains cerebral and myocardial blood flow rates during prolonged CPR. Finally, to establish the effect of c ompression rate and duty cycle on cerebral and myocardial blood flow r ates during vest CPR in this model. Design: Prospective, randomized co mparison of two compression rates and two duty cycles in four groups d uring prolonged CPR. Setting: University cerebral resuscitation labora tory. Subjects: Thirty-two infant domestic swine. Interventions: Micro sphere-determined cerebral and myocardial blood flow rates, perfusion pressures, and chest dimensions, were measured before and during prolo nged vest CPR Immediately after ventricular fibrillation, epinephrine administration was started and thoracic vest CPR was performed using a single combination of compression rates of 100 or 150/ min and duty c ycles of 30% or 60%. Measurements were made before and at 5, 10, 20, 3 5, and 50 mins of CPR. Measurements and Main Results: Five minutes int o CPR, between-group comparisons showed that cerebral blood flow was 1 6 to 20 mL/min/100 g and myocardial blood flow was 34 to 45 mL/min/100 g (48% to 62% and 25% to 33% of prearrest values). When CPR was prolo nged, cerebral blood Bow deteriorated similarly in all groups. Myocard ial blood flow decreased over time but was better maintained in the gr oups with a 30% duty cycle (24 vs. 4 mL/min/100 g; p < .006). There we re no differences between the two compression rates. Chest deformity a fter cessation of 50 mins of compression was < 3%. Conclusions: Cerebr al and myocardial blood flow rates produced by vest CPR are comparable with rates reported using other types of CPR in this model. Deteriora tion in blood flow during prolonged CPR occurs despite a lack of chest deformation. The deterioration in myocardial blood flow during prolon ged CPR is greater when a long duty cycle is used in this model.