CRD summary

The authors concluded that the use of cardiopulmonary resuscitation (CPR) plus automated external defibrillators (AED) by trained non-healthcare professionals offered a survival advantage compared to only CPR in participants with out-of-hospital cardiac arrest (OHCA). This was a generally well-conducted review, however, the small number of available studies suggest a more cautious conclusion may be appropriate.

Authors' objectives

To compare the effectiveness of cardiopulmonary resuscitation (CPR) alone and CPR plus automated external defibrillator (AED) for out-of-hospital cardiac arrest (OHCA).

Searching

Pubmed, EMBASE, Cochrane CENTRAL Register and the Cochrane Collaboration were searched from inception to July 2007. Search terms were reported. Published resuscitation guidelines were consulted and major journals, conference proceedings and abstracts were handsearched. Other researchers were contacted for information about published trials.

Study selection

Randomised controlled trials (RCT) of CPR alone compared to CPR with AED used by non-healthcare professionals as a first-response treatment and measuring survival in participants with OHCA were eligible for inclusion. The included interventions were delivered by trained fire fighters, trained police or trained volunteer lay rescuers. One of the studies was classed as a non-randomised trial with a crossover design. Outcomes reported in included studies were survival to hospital admission and to discharge. Where reported, the mean age of participants in the included studies ranged from 64.1 to 67 years and the proportion of men ranged from 61 per cent to 77 per cent. All studies were carried out in urban settings.

The study selection was performed independently by two researchers.

Assessment of study quality

The methodological quality of included studies was assessed independently by two reviewers using the Jadad scale to assess randomisation, blinding, withdrawals and allocation concealment. The maximum achievable score was 5; only those scoring 3 or more were eligible for inclusion in the review.

Data extraction

Data were extracted independently by two reviewers. Data extracted were number of participants surviving to hospital admission and hospital discharge for CPR alone and CPR plus AED groups. Data were collected in order to calculate the number needed to treat (NNT). Data were analysed on intention-to-treat principles.

Methods of synthesis

Pooled relative risks (RR) with 95% confidence intervals (CI) were calculated using a random-effects model. Statistical heterogeneity was assessed using the Χ² test. A sensitivity analysis was carried out excluding the non-randomised trial. Funnel plots were used to assess for publication bias.

Results of the review

Three studies were included (n=1,583): two RCTs (n=704) and one non-randomised trial with a crossover design (n=879). All included studies were of generally good quality (one scored 4 on the Jadad scale and the others scored 3). Blinding was not possible in any of the studies.

CPR plus AED was associated with significantly greater chances of survival to hospital admission compared to CPR alone (RR 1.22, 95%CI: 1.04, 1.43, p=0.014). The NNT with CPR plus AED to gain one survival to hospital admission was 17 (NNT 17). CPR plus AED was also associated with significantly greater survival to hospital discharge compared to CPR alone (RR 1.39, 95% CI: 1.06, 1.83 p=0.019). The NNT with CPR plus AED to gain one survival to hospital discharge was 24 (NNT 24). When the non-randomised trial was excluded in a sensitivity analysis, CPR plus AED continued to show significant benefits in survival to hospital admission (RR 1.34, 95%CI: 1.09, 1.64) and survival to hospital discharge (RR 1.38, 95% CI: 0.99, 1.92).

There was no evidence of statistical heterogeneity for either of the outcomes. From examination of the funnels plots, the reviewers report that publication bias may exist.

Authors' conclusions

The use of CPR plus AED by trained non-healthcare professionals offers a survival advantage compared to CPR only in participants with OHCA.

CRD commentary

Inclusion criteria for intervention, participants, outcomes and study design were well defined and the rationale for the inclusion of a non-randomised study was stated clearly. Several relevant sources were searched with no language restrictions, thereby minimising the risk of language bias. Limited attempts were made to identify unpublished data. Publication bias was assessed using funnel plots and could not be ruled out. Appropriate steps were taken in the study selection, data extraction and validity assessment process to minimise reviewer error and bias. Methodological quality was assessed using a recognised tool and only studies of good quality were included. Statistical heterogeneity was assessed and the choice of meta-analysis was appropriate. Given that all the included studies were conducted in urban settings, it is unclear to what extent the findings may be generalised to other settings. This is a generally well-conducted review, however, the small number of available studies and the possibility of publication bias suggest a more cautious conclusion may be more appropriate.

Implications of the review for practice and research

Practice: the authors do not state any implications for practice.

Research: the authors do not state any implications for research.

Funding

Not stated.

Bibliographic details

Sanna T, La Torre G, de Waure C, Scapigliati A, Ricciardi W, Dello Russo A, Pelargonio G, Casella M, Bellocci F. Cardiopulmonary resuscitation alone vs cardiopulmonary resuscitation plus automated external defibrillator use by non-healthcare professionals: a meta-analysis on 1583 cases of out-of-hospital cardiac arrest. Resuscitation 2008; 76(2): 226-232. [PubMed: 17875357]

Indexing Status

Subject indexing assigned by NLM

MeSH

Cardiopulmonary Resuscitation /methods; Caregivers; Defibrillators; Electric Countershock /instrumentation; Emergency Medical Services /methods; Heart Arrest /therapy; Humans; Randomized Controlled Trials as Topic

AccessionNumber

12008103028

Database entry date

02/03/2009

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.