Abstract
Background The American Heart Association recommends use of physiologic feedback when available to optimize chest compression delivery. We compared hemodynamic parameters during cardiopulmonary resuscitation in which either end-tidal carbon dioxide ( ETCO (2)) or diastolic blood pressure ( DBP ) levels were used to guide chest compression delivery after asphyxial cardiac arrest. Methods and Results One- to 2-week-old swine underwent a 17-minute asphyxial-fibrillatory cardiac arrest followed by alternating 2-minute periods of ETCO (2)-guided and DBP -guided chest compressions during 10 minutes of basic life support and 10 minutes of advanced life support. Ten animals underwent resuscitation. We found significant changes to ETCO (2) and DBP levels within 30 s of switching chest compression delivery methods. The overall mean ETCO (2) level was greater during ETCO (2)-guided cardiopulmonary resuscitation (26.4±5.6 versus 22.5±5.2 mm Hg; P=0.003), whereas the overall mean DBP was greater during DBP -guided cardiopulmonary resuscitation (13.9±2.3 versus 9.4±2.6 mm Hg; P=0.003). ETCO (2)-guided chest compressions resulted in a faster compression rate (149±3 versus 120±5 compressions/min; P=0.0001) and a higher intracranial pressure (21.7±2.3 versus 16.0±1.1 mm Hg; P=0.002). DBP -guided chest compressions were associated with a higher myocardial perfusion pressure (6.0±2.8 versus 2.4±3.2; P=0.02) and cerebral perfusion pressure (9.0±3.0 versus 5.5±4.3; P=0.047). Conclusions Using the ETCO (2) or DBP level to optimize chest compression delivery results in physiologic changes that are method-specific and occur within 30 s. Additional studies are needed to develop protocols for the use of these potentially conflicting physiologic targets to improve outcomes of prolonged cardiopulmonary resuscitation.