EFFECTS OF ACTIVE COMPRESSION-DECOMPRESSION RESUSCITATION ON MYOCARDIAL AND CEREBRAL BLOOD-FLOW IN PIGS

Background. This study was designed to assess the effects of a modifie d cardiopulmonary resuscitation (CPR) technique that consists of both active compression and active decompression of the chest (ACD CPR) ver sus standard CPR (STD CPR) on myocardial and cerebral blood flow durin g ventricular fibrillation both before and after epinephrine administr ation. Methods and Results. During a 30-second period of ventricular f ibrillation cardiac arrest, 14 pigs were randomized to receive either STD CPR (n=7) or ACD CPR (n=7), Both STD and ACD CPR were performed us ing an automated pneumatic piston device applied midsternum, designed to provide either active chest compression (1.5 to 2.0 in.) and decomp ression or only active compression of the chest at 80 compressions per minute and 50% duty cycle. Using radiolabeled microspheres, median to tal myocardial blood flow after 5 minutes of ventricular fibrillation was 14 (7 to 30, minimum to maximum) STD CPR versus 30 (9 to 46) mL . min-1 . 100 g-1 with ACD CPR (P<.05). Median cerebral blood flow was 1 5 (10 to 26) mL . min-1 . 100 g-1 with STD CPR and 30 (21 to 39) with ACD CPR (P<.01). When comparing STD with ACD CPR, aortic systolic (62 mm Hg [48 to 70] vs 80 [59 to 86]) and diastolic (22 [18 to 28] vs 28 [21 to 36]) pressures, calculated coronary systolic (30 [22 to 361 vs 49 [37 to 56]) and diastolic (18 [16 to 23] vs 26 [21 to 31]) perfusio n pressures, end-tidal CO2 (1.4% [0.8 to 1.8] vs 2.1 (1.8 to 2.4]), ce rebral O2 delivery (3.1 mL . min-1 . 100 g-1 [1.5 to 4.5] vs 5.3 [3.8 to 7.5]), and cerebral perfusion pressure (14 mm Hg [4 to 22] vs 26 [6 to 34]) were all significantly higher with ACD CPR. To compare these parameters before and after vasopressor therapy, a bolus of high-dose epinephrine (0.2 mg/kg) was given to all animals after 5 minutes of ve ntricular fibrillation. Organ blood flow and calculated perfusion pres sures increased significantly in both the STD and ACD groups after epi nephrine. The differences observed between STD and ACD CPR before epin ephrine were diminished 90 seconds after epinephrine but were again st atistically significant when assessed 5 minutes later, once the acute effects of epinephrine had decreased. No difference in short-term resu scitation success was found between the two groups. Conclusions. We co nclude that ACD CPR significantly increases myocardial and cerebral bl ood flow during cardiac arrest in the absence of vasopressor therapy c ompared with STD CPR.