Clinical Question: Which method of resuscitation optimizes outcomes of out-of-hospital cardiac arrest: manual chest compression or the use of an automated chest compression device?

Setting: Population-based

Study Design: Randomized controlled trial (nonblinded)

Allocation: Unconcealed

Synopsis: The investigators randomized (allocation not concealed) 1,071 eligible adults 18 years or older, with out-of-hospital cardiac arrest presumed to be of cardiac origin, to cardiopulmonary resuscitation (CPR) via standard manual chest compression or the use of an automated load-distributing band (LDB) chest compression device. Study outcomes included survival with spontaneous circulation at four hours, survival to hospital discharge, and neurologic function at discharge.

Individuals assessing outcomes were not blinded to treatment group survival, but the major outcome of interest (i.e., mortality) is not subject to interpretation. Follow-up occurred for all eligible patients until hospital discharge. Using intention-to-treat analysis, no significant difference occurred in the end point of survival to four hours between the manual CPR and LDB groups. Survival to hospital discharge was nonsignificantly higher in the manual CPR group than in the LDB group (9.9 versus 5.8 percent), but the safety monitoring board stopped the study before completion. Neurologic outcome at hospital discharge was significantly better in the manual CPR group, with 7.5 versus 3.1 percent of patients achieving a cerebral performance category score of 1 or 2.

A similar report in the same issue (Ong ME, et al. Use of an automated, load-distributing band chest compression device for out-of-hospital cardiac arrest resuscitation. JAMA 2006;295:2629–37) used a before-after study design; in that study, resuscitation with a LDB device was associated with a slightly but significantly improved rate of survival to hospital discharge. However, among patients surviving to hospital discharge, overall neurologic outcomes were similar between groups. In an accompanying editorial in the same issue (Lewis RJ, Niemann JT. Manual vs device-assisted CPR: reconciling apparently contradictory results. JAMA 2006;295:2661–4) the authors indicate that the seemingly contradictory results are most likely the result of methodologic differences and possible sources of bias in both studies, including the differences in deployment time required for the LDP device, enrollment bias caused by the nonconcealed allocation assignment, and the potential for the Hawthorne effect (i.e., improved performance during the study as a result of being closely observed) in the manual CPR group.

Bottom Line: Current evidence is unable to support a recommendation for the use of manual chest compression or an automated chest compression device for out-of-hospital cardiac arrest resuscitation. Overall survival with good neurologic function at hospital discharge occurs in fewer than 10 percent of individuals with the use of either CPR method. (Level of Evidence: 1b–)