Abstract 2230: Lower Extremity Counterpulsation During The Decompression Phase of CPR Improves Hemodynamics And Provides Continuous Forward Carotid Blood Flow.

Abstract

Background: We hypothesize that lower extremity counterpulsations (LECP) during the decompression phase of CPR will increase diastolic aortic pressure without raising the intracranial pressure (ICP) and significantly increase forward carotid blood flow. Methods: In 6 (24±4Kg) pigs, 4 minutes of untreated VF were followed by 2 minutes epochs of standard (STD) CPR, STD +LECP, active compression decompression (ACD) +ITD and ACD + inspiratory impedance threshold device (ITD)+LECP. Compressions and ventilations were performed according to the 2005 AHA guidelines. A large blood pressure cuff that was circumferentially placed around the pig’s thighs avoiding the abdominal cavity was inflated with air to the point that manometer pressure started to rise. Compressions over the cuff were performed manually and synchronized with the thoracic decompression phase. The cuff was compressed up to 200mmHg. Basic hemodynamic parameters and common carotid blood flow (CCBF) (ml/min) were continuously measured. Cerebral perfusion pressure (CerPP) (mean arterial pressure - mean ICP) and CPP (diastolic AoP - diastolic RAP) were calculated at the end of the 2 minute epochs. Statistical analysis was performed with ANOVA. Results: LECP significantly increased diastolic aortic pressure, CPP and CerPP both when added on STD and on ACD+ITD CPR. The largest benefit was observed with ACD+ITD+LECP were there was a 2-fold increase in CPP and CerPP with a 2.5-fold increase in common carotid blood flow compared to STD CPR. LECP did not alter ICP. (Table 1 ). Decompression phase CCBF during ACD+ITD+LECP CPR was positive and reached pre cardiac arrest levels. Conclusion: LECP during thoracic decompression significantly augmented aortic diastolic pressure, CPP and CerPP without increasing the ICP . LECP led to a continuous positive cerebral perfusion pressure gradient during CPR cycles and in combination with ACD + ITD CPR common carotid blood flow reached pre-arrest levels. Hemodynamic Parameters