Robert A. Berg, MD; Arthur
B. Sanders, MD; Karl B. Kern, MD; Ronald W. Hilwig,
DVM, PhD; Joseph W. Heidenreich, BA; Matthew E.
Porter, BA; Gordon A. Ewy, MD
From the University of
Arizona College of Medicine, Steele Memorial Children’s Research Center and
Department of Pediatrics (R.A.B.), Sarver Heart Center (all authors),
Department of Surgery (A.B.S.), and Department of Medicine (K.B.K., G.A.E.),
Tucson, Ariz.
Correspondence to Robert A.
Berg, MD, University of Arizona, Department of Pediatrics/3302, PO Box 245073,
Tucson, AZ 85724-5073. E-mail rberg@peds.arizona.edu
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.
Methods and 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.
Key Words:
cardiopulmonary resuscitation • heart arrest • hemodynamics
• fibrillation • ventilation