EVALUATION OF STANDARD AND ACTIVE COMPRESSION-DECOMPRESSION CPR IN ANACUTE HUMAN-MODEL OF VENTRICULAR-FIBRILLATION

Background The mechanisms that underlie cardiopulmonary resuscitation (CPR) in humans remain controversial and difficult to study. This repo rt describes a new human model to evaluate CPR during the first 1 to 2 minutes after the onset of ventricular fibrillation (VF). With this m odel, standard CPR was compared with active compression-decompression (ACD) CPR, a method that uses a handheld suction device to actively co mpress and actively decompress the chest. Methods and Results During r outine inductions of VF as part of a transvenous lead cardioverter/def ibrillator implantation procedure, CPR was performed in 21 patients if the first defibrillation shock failed and until a successful rescue s hock was delivered. Compressions during CPR were performed according t o American Heart Association guidelines. For ACD CPR, decompression wa s performed with up to -30 lbs. Radial arterial and right atrial press ures were measured in all patients. Esophageal pressures, intratrachea l pressures, or minute ventilation was measured in the last 13 patient s. Application of both CPR techniques increased arterial and right atr ial pressures. The mean coronary perfusion pressure was increased thro ughout the entire CPR cycle with ACD CPR (compression, 21.5+/-9.0 mmHg ; decompression, 21.9+/-8.7 mm Hg) compared with standard CPR (compres sion, 17.9+/-8.2 mm Hg; decompression, 18.5+/-6.9 mm Hg; P<.02 and P<. 02, respectively). Ventilation per compression-decempression cycle was 97.3+/-65.6 mt with standard CPR and 168.4+/-68.6 mt with ACD CPR (n= 7, P<.001). Negative inspiratory pressure was -0.8+/-4.8 mm Hg with st andard CPR and -11.4+/-6.3 mm Hg with ACD CPR (n=6, P<.04). Conclusion s Patients undergoing multiple inductions of VF during cardioverter/de fibrillator implantation with transvenous leads provide a well-control led and reproducible model to study the mechanisms of CPR. Using this model, ACD CPR significantly increased arterial blood pressure, corona ry perfusion pressure, minute ventilation, and negative inspiratory pr essure compared with standard CPR.