Clinical and hemodynamic comparison of 15:2 and 30:2 compression-to-ventilation ratios for cardiopulmonary resuscitation.

ABSTRACT

OBJECTIVE: To compare cardiopulmonary resuscitation (CPR) with a compression to ventilation (CV) ratio of 152 vs. 302, with and without use of an impedance threshold device (ITD). DESIGN: Prospective randomized animal and manikin study. SETTING: Animal laboratory and emergency medical technician training facilities. SUBJECTS: Twenty female pigs and 20 Basic Life Support (BLS)-certified rescuers. ANIMALS Acid-base status, cerebral, and cardiovascular hemodynamics were evaluated in 18 pigs in cardiac arrest randomized to a CV ratio of 152 or 302. After 6 mins of cardiac arrest and 6 mins of CPR, an ITD was added. Compared to 152, 302 significantly increased diastolic blood pressure (20 +/- 1 to 26 +/- 1; p < .01); coronary perfusion pressure (18 +/- 1 to 25 +/- 2; p = .04); cerebral perfusion pressure (16 +/- 3 to 18 +/- 3; p = .07); common carotid blood flow (48 +/- 5 to 82 +/- 5 mL/min; p < .001); end-tidal CO2 (7.7 +/- 0.9 to 15.7 +/- 2.4; p < .0001); and mixed venous oxygen saturation (26 +/- 5 to 36 +/- 5, p < .05). Hemodynamics improved further with the ITD. Oxygenation and arterial pH were similar. Only one of nine pigs had return of spontaneous circulation with 152, vs. six of nine with 302 (p < 0.03). HUMANS Fatigue and quality of CPR performance were evaluated in 20 BLS-certified rescuers randomized to perform CPR for 5 mins at 152 or 302 on a recording CPR manikin. There were no significant differences in the quality of CPR performance or measurement of fatigue. Significantly more compressions per minute were delivered with 302 in both the animal and human studies. CONCLUSIONS: These data strongly support the contention that a ratio of 302 is superior to 152 during manual CPR and that the ITD further enhances circulation with both CV ratios.