A preliminary study of dispatcher-instructed bystander cardiopulmonary resuscitation and a subsequent study of CPR in swine suggested that chest compression alone may be as effective as compression plus mouth-to-mouth ventilation. Prompted by these findings, investigators tested the hypothesis that dispatcher-instructed bystander CPR by chest compression alone would increase survival to hospital discharge by at least 3.5 percent over compression plus mouth-to-mouth.
Callers to an urban emergency medical system were assigned randomly to receive instruction in CPR by 1 of the 2 methods. Of 1296 calls, 776 were excluded on the basis of predetermined criteria and the remaining 520 were randomized. A total of 64 patients (12.3 percent) survived to hospital discharge, 14.6 percent of the chest-compression-only group and 10.4 percent of the compression-plus-mouth-to-mouth group; the difference was not statistically significant (P=0.18). When these data were combined with results from a preliminary (and identically designed) study, the lack of a statistically significant difference between groups was preserved. Age, location of arrest, and whether arrest was witnessed were predictors of survival to discharge.
Comment: The authors conclude that there is no difference in outcome between the 2 methods and that chest compression alone may be sufficient for bystander CPR to be effective. This is probably true, but failure to demonstrate a difference in a study such as this doesn't necessarily mean that there is no difference. Nevertheless, given the prestige of the New England Journal of Medicine, no one will blame a bystander for omitting mouth-to-mouth resuscitation from CPR.
— JS Bohan
Published in Journal Watch Emergency Medicine July 5, 2000