Authors: Stiell IG et al., Circulation 2014 Sep 24;
A large prehospital study found that survival was highest when chest compression depths were between 4.0 and 5.5 cm.
In 2010, the American Heart Association (AHA) suggested an increase in the target depth of chest compressions to at least 5 cm. However, there have been no large clinical trials to determine whether this depth is optimal. Investigators from the Resuscitations Outcomes Consortium analyzed prospectively gathered data from a randomized trial and a large registry to determine the association between compression depth (the accelerometer-measured posterior depression of the anterior chest wall) and survival to hospital discharge.
Of 9266 patients with out-of-hospital cardiac arrest, 31% had return of spontaneous circulation and 7% survived to hospital discharge. In both men and women, survival increased with compression depth until it peaked at a depth of 4.6 cm (adjusted odds ratio for survival, 1.04 per 5-mm increment). Survival was highest when compression depth was between 4.0 and 5.5 cm.
Effective cardiopulmonary resuscitation requires high-quality chest compressions, and we should aim for a compression depth of 4.0 to 5.5 cm. Notably, 36% of cases in this study still had an average depth less than 3.8 cm (the minimum depth recommended in the old 2005 AHA guidelines), so we still need to push a little harder. Real-time feedback from an accelerometer will help providers achieve this target depth.