REVIEW QUESTION

In patients with non-asphyxial out-of-hospital cardiac arrest (OHCA), which method of CPR-continuous or interrupted chest compressions-will better enable survival to hospital admission or discharge?

TYPE OF REVIEW

A systematic review of four randomized controlled trials (RCTs).

RELEVANCE FOR NURSING

OHCA affects approximately 700,000 people annually in the United States and Europe. It is estimated that only about one in 10 patients suffering OHCA will survive to hospital discharge. Early, high-quality CPR is associated with improved survival rates. For many years, conventional CPR required chest compressions to be interrupted for rescue breaths-most recently at a ratio of 30 compressions to two breaths. Continuous chest compressions, on the other hand, are characterized by rescue breaths given either asynchronously or not at all.

CHARACTERISTICS OF THE EVIDENCE

This review sought to identify differences in patient outcomes between continuous chest compressions with or without rescue breathing (intervention group) and chest compressions interrupted by rescue breathing (control group), specifically in non-asphyxial OHCA. Non-asphyxial cardiac arrest is related to abnormalities in cardiac function, unlike asphyxial cardiac arrest, which is related to reduced oxygen levels (due to choking or drowning, for example). Four studies were included in the review: three RCTs and one cluster RCT, for a total of 26,742 patients. In three studies, CPR was delivered by untrained bystanders listening to emergency medical service (EMS) instructions by telephone; in the remaining study, CPR was provided by EMS professionals.

Primary outcomes were survival to hospital admission with spontaneous circulation and a measurable blood pressure, and survival to hospital discharge. Secondary outcomes included return of spontaneous circulation (ROSC) and neurologic outcomes.

In the three untrained bystander-CPR studies (n = 3,031), the pooled data on survival to discharge showed better survival for the intervention group than the control group (14% versus 11.6%). In one trial (n = 520) there was no significant difference in survival to hospital admission between the two groups. Similarly, another trial (n = 1,286) reported no significant differences in neurologic outcomes between the groups.

In the one EMS professional-CPR study (n = 23,711), participants received either the intervention (continuous chest compressions [100 per minute] and asynchronous rescue breathing [10 per minute]) or the control CPR (interrupted chest compressions with pauses for rescue breathing at a 30:2 ratio). Compared with the control group, the intervention group had a not significantly lower survival-to-discharge rate (9% versus 9.7%) and a significantly lower survival-to-admission rate (24.6% versus 25.9%). There were no significant differences in rates of ROSC or in neurologic outcomes.

BEST PRACTICE RECOMMENDATIONS

When delivered by untrained bystanders receiving instruction over the telephone, CPR consisting of continuous compressions with no rescue breaths is associated with higher rates of survival to hospital discharge than conventional, interrupted chest compressions and rescue breathing. In the case of CPR performed by EMS professionals, continuous chest compressions did not yield better outcomes.

RESEARCH RECOMMENDATIONS

More research into this issue is required, particularly on the impact of increased automatic external defibrillator availability and the use of continuous chest compressions in pediatric cardiac arrest.

REFERENCE