Extracorporeal membrane oxygenation in infants with congenital diaphragmatic hernia: a systematic review of the evidence.

AIM: The aim of this study was to evaluate the evidence supporting the use of extracorporeal membrane oxygenation (ECMO) in infants with congenital diaphragmatic hernia (CDH) and severe respiratory failure.

METHODS

Medline, Embase, ISI Current Contents and Biosis databases were searched using a defined strategy. Case reports and opinion articles were excluded. We performed: 1) a systematic review of non randomised studies comparing mortality when ECMO was not available with a period when ECMO was available. Mortality was classified as "early" (before hospital discharge) and "late" (after discharge). Patients were classified as "ECMO" and "non-ECMO" candidates according to criteria reported by the authors; 2) a meta-analysis of randomised controlled trials (RCTs) comparing ECMO and conventional mechanical ventilation (CMV). Differences in mortality are reported as relative risk (RR) and 95 % confidence intervals.

RESULTS

A) SYSTEMATIC REVIEW: 658 studies and 21 (2043 patients) fulfilled the entry criteria. Both early (RR 0.60 [0.51-0.70]; p < 0.001) and late mortality (RR 0.63 [0.53-0.73]; p < 0.001) were significantly lower when ECMO was available than when ECMO was unavailable. This difference in mortality was observed in "ECMO candidates" (RR 0.46 [0.32-0.68]; p < 0.001) but not in "non-ECMO candidates" (RR 0.80 [0.58-1.10]; p = 0.17). B) META-ANALYSIS: 3 trials comparing ECMO and conventional ventilation were identified which included 39 infants with CDH. The early mortality was significantly lower with ECMO compared to CMV (RR 0.73 [95 % CI 0.55-0.99]; p < 0.04), however, late mortality was similar in the two groups (RR 0.83 [0.66-1.05]; p = 0.12).

CONCLUSIONS

Non randomised studies suggest a reduction in mortality with ECMO. However, differences in the indications for ECMO and improvements in other treatment modalities may contribute to this reduction. The meta-analysis of RCTs indicates a reduction in early mortality with ECMO but no long-term benefit. A large RCT in infants with CDH and severe respiratory failure is warranted.