Good samaritans who skip mouth-to-mouth resuscitation while giving chest compression are more than twice as likely to save MI victims than those who give traditional CPR, Japanese research shows.
Investigators studied 4,068 adults who collapsed from cardiac arrest in front of witnesses. Current international guidelines in such situations call for 30 chest compressions, followed by two mouth-to-mouth ventilations, and 30 more compressions. But the study found that compression-only resuscitation worked better for patients with apnea (6.2% survival vs. 3.1% survival), or shockable rhythm (19.4% vs. 11.2%) and for those who started receiving the compressions within four minutes of arrest (10.1% vs. 5.1%). There was no benefit from adding mouth-to-mouth rescue in any subgroup, the researchers report in The Lancet (2007;369:920-26).
Gordon A. Ewy, MD, director of the Sarver Heart Center in Tucson and a long-time advocate of compression, faults guidelines for recommending the same approach for different conditions. “In primary cardiac arrest, the arterial blood is well oxygenated at the time of the arrest, whereas in respiratory arrest, arterial blood is so severely desaturated that it contributes to the low blood pressure and secondary cardiac arrest,” Dr. Ewy explains. “In cardiac arrest, the forward blood flow through chest compression is so marginal that interrupting that for anything, including ventilation, is lethal.”
Respiratory arrest occurs in drowning, drug overdose, asphyxia, and most cases cases of sudden collapse that involve children.
Mouth-to-mouth resuscitation also deters bystanders for fear of contracting a disease and because of the complexity of the technique. In the new study, 72% of the MI victims received no CPR at all despite the presence of witnesses.