title: Adverse hemodynamic effects of interrupting chest compressions for rescue breathing during cardiopulmonary resuscitation for ventricular fibrillation cardiac arrest.
abstract: BACKGROUND
  Despite improving arterial oxygen saturation and pH, bystander cardiopulmonary resuscitation (CPR) with chest compressions plus rescue breathing (CC+RB) has not improved survival from ventricular fibrillation (VF) compared with chest compressions alone (CC) in numerous animal models and 2 clinical investigations.
  
  
  RESULTS
  After 3 minutes of untreated VF, 14 swine (32+/-1 kg) were randomly assigned to receive CC+RB or CC for 12 minutes, followed by advanced cardiac life support. All 14 animals survived 24 hours, 13 with good neurological outcome. For the CC+RB group, the aortic relaxation pressures routinely decreased during the 2 rescue breaths. Therefore, the mean coronary perfusion pressure of the first 2 compressions in each compression cycle was lower than those of the final 2 compressions (14+/-1 versus 21+/-2 mm Hg, P<0.001). During each minute of CPR, the number of chest compressions was also lower in the CC+RB group (62+/-1 versus 92+/-1 compressions, P<0.001). Consequently, the integrated coronary perfusion pressure was lower with CC+RB during each minute of CPR (P<0.05 for the first 8 minutes). Moreover, at 2 to 5 minutes of CPR, the median left ventricular blood flow by fluorescent microsphere technique was 60 mL. 100 g(-1). min(-1) with CC+RB versus 96 mL. 100 g(-1). min(-1) with CC, P<0.05. Because the arterial oxygen saturation was higher with CC+RB, the left ventricular myocardial oxygen delivery did not differ.
  
  
  CONCLUSIONS
  Interrupting chest compressions for rescue breathing can adversely affect hemodynamics during CPR for VF.
authors.affiliation: University of Arizona College of Medicine, Steele Memorial Children's Research Center, Department of Pediatrics, Sarver Heart Center, Tucson, Arizona, USA. rberg@peds.arizona.edu
authors.forename: R A
authors.initials: RA
authors.lastname: Berg
authors.forename: A B
authors.initials: AB
authors.lastname: Sanders
authors.forename: K B
authors.initials: KB
authors.lastname: Kern
authors.forename: R W
authors.initials: RW
authors.lastname: Hilwig
authors.forename: J W
authors.initials: JW
authors.lastname: Heidenreich
authors.forename: M E
authors.initials: ME
authors.lastname: Porter
authors.forename: G A
authors.initials: GA
authors.lastname: Ewy
mesh_terms: D000818:Animals; D001794:Blood Pressure; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D003326:Coronary Circulation; D006323:Heart Arrest / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D006336:Heart Massage / Q000379:methods*; D006439:Hemodynamics; D009206:Myocardium / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D012121:Respiration, Artificial / Q000009:adverse effects*; D013552:Swine; D014693:Ventricular Fibrillation / Q000628:therapy*
chemical_list: D010100:Oxygen