Nicolas Segal1, Aaron E Robinson2, Paul S Berger3, Michael C Lick4, Johanna C Moore5, Bayert J Salverda2, Mason B Hinke2, Andrew A Ashton6, Angela M McArthur6, Keith G Lurie7, Anja K Metzger8. 1. Department of Emergency Medicine, University of Minnesota, Minneapolis, MN, United States. 2. Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, MN, United States. 3. ZOLL Medical, Minneapolis, MN, United States. 4. Minneapolis Medical Research Foundation, Hennepin County Medical Center, Minneapolis, MN, United States. 5. Department of Emergency Medicine, University of Minnesota, Minneapolis, MN, United States; Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, MN, United States. 6. Anatomy Bequest Program, University of Minnesota Medical School, Minneapolis, MN, United States. 7. Department of Medicine, Cardiovascular Division, University of Minnesota, Minneapolis, MN, United States. 8. Department of Emergency Medicine, University of Minnesota, Minneapolis, MN, United States; ZOLL Medical, Minneapolis, MN, United States. Electronic address: kohl0005@umn.edu.
Abstract
INTRODUCTION: Chest compliance plays a fundamental role in the generation of circulation during cardiopulmonary resuscitation (CPR). To study potential changes in chest compliance over time, anterior posterior (AP) chest height measurements were performed on newly deceased (never frozen) human cadavers during CPR before and after 5min of automated CPR. We tested the hypothesis that after 5min of CPR chest compliance would be significantly increased. METHODS: Static compression (30, 40, and 50kg) and decompression forces (-10, -15kg) were applied with a manual ACD-CPR device (ResQPUMP, ZOLL) before and after 5min of automated CPR. Lateral chest x-rays were obtained with multiple reference markers to assess changes in AP distance. RESULTS: In 9 cadavers, changes (mean±SD) in the AP distance (cm) during the applied forces were 2.1±1.2 for a compression force of 30kg, 2.9±1.3 for 40kg, 4.3±1.0 for 50kg, 1.0±0.8 for a decompression force of -10kg and 1.8±0.6 for -15kg. After 5min of automated CPR, AP excursion distances were significantly greater (p<0.05). AP distance increased to 3.7±1.4 for a compression force of 30kg, 4.9±1.6 for 40kg, 6.3±1.9 for 50kg, 2.3±0.9 for -10kg of lift and 2.7±1.1 for -15kg of lift. CONCLUSIONS: These data demonstrate chest compliance increases significantly over time as demonstrated by the significant increase in the measured AP distance after 5min of CPR. These findings suggest that adjustments in compression and decompression forces may be needed to optimize CPR over time.
INTRODUCTION: Chest compliance plays a fundamental role in the generation of circulation during cardiopulmonary resuscitation (CPR). To study potential changes in chest compliance over time, anterior posterior (AP) chest height measurements were performed on newly deceased (never frozen) human cadavers during CPR before and after 5min of automated CPR. We tested the hypothesis that after 5min of CPR chest compliance would be significantly increased. METHODS: Static compression (30, 40, and 50kg) and decompression forces (-10, -15kg) were applied with a manual ACD-CPR device (ResQPUMP, ZOLL) before and after 5min of automated CPR. Lateral chest x-rays were obtained with multiple reference markers to assess changes in AP distance. RESULTS: In 9 cadavers, changes (mean±SD) in the AP distance (cm) during the applied forces were 2.1±1.2 for a compression force of 30kg, 2.9±1.3 for 40kg, 4.3±1.0 for 50kg, 1.0±0.8 for a decompression force of -10kg and 1.8±0.6 for -15kg. After 5min of automated CPR, AP excursion distances were significantly greater (p<0.05). AP distance increased to 3.7±1.4 for a compression force of 30kg, 4.9±1.6 for 40kg, 6.3±1.9 for 50kg, 2.3±0.9 for -10kg of lift and 2.7±1.1 for -15kg of lift. CONCLUSIONS: These data demonstrate chest compliance increases significantly over time as demonstrated by the significant increase in the measured AP distance after 5min of CPR. These findings suggest that adjustments in compression and decompression forces may be needed to optimize CPR over time.