Is Extracorporeal Membrane Oxygenation the Standard Care for Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

Abstract

Background: Acute respiratory distress syndrome (ARDS) is a type of acute respiratory failure syndrome characterised by severe respiratory distress and stubborn hypoxaemia. Patients with ARDS have a prolonged hospital stay and high mortality rate. Over long-term follow-up, ARDS is found to be associated with a high incidence of long-term complications and decreased quality of life. Venovenous extracorporeal membrane oxygenation (vv-ECMO) has been widely used for the treatment of refractory ARDS. However, it is not the standard treatment as recommended by ARDS guidelines.

Aim: The aim of this study was to compare the effects of ECMO (vv-ECMO) and conventional mechanical ventilation (CMV) on the clinical outcomes in patients with ARDS.

Method: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Medline, EMBASE, Web of Science, and PubMed databases up to November 2019. We selected appropriate studies according to our inclusion and exclusion criteria, and extracted and analysed the data using RevMan 5.0 software to evaluate the effectiveness of ECMO systematically.

Results: A total of 18 articles and 2,399 patients were included in this meta-analysis: 898 patients in the ECMO group and 1,501 patients in the CMV group. Treatment with ECMO may be associated with reduced 1-year mortality (95% confidence interval [CI], 0.27-0.83; p=0.009) and 60-day mortality (95% CI, 0.37-0.86; p=0.008), but increased Intensive Care Unit mortality (95% CI, 1.26-2.36; p=0.0007) of patients with ARDS. Extracorporeal membrane oxygenation may not be related to 30-day mortality or complications such as nosocomial pneumonia, haemorrhagic stroke, or continuous renal replacement therapy in patients with ARDS. However, some results showed heterogeneity, such as bleeding complications and in-hospital mortality. Subgroup analysis showed that ECMO treatment might increase ICU mortality (p=0.002) and nosocomial pneumonia complications (p=0.03) in patients with H1N1 ARDS.

Conclusions: Compared with CMV, ECMO contributed to lower 60-day and 1-year mortality, and increased ICU mortality in patients with ARDS. However, H1N1 ARDS was independently associated with higher ICU mortality and nosocomial pneumonia. The results were not affected by removing retrospective control studies or articles published >20 years ago from the sensitivity analysis. This meta-analysis demonstrates the effectiveness of ECMO and its importance in standard treatment of patients with ARDS.

Keywords: ARDS; Complications; ECMO; H1N1; Mortality.

Figure 1

Study flowchart.

Figure 2

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: 30-day mortality (Mantel–Haenszel statistic [MH], 1.37; 95% confidence interval [CI] –0.62 to 3.00; n=3).

Figure 3

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: 60-day mortality (Mantel–Haenszel statistic [MH], 0.57; 95% confidence interval [CI], 0.37–0.86; n=3).

Figure 4

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: Intensive Care Unit mortality (Mantel–Haenszel statistic [MH], 1.72; 95% confidence interval [CI], 1.26–2.36; n=6).

Figure 5

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: in-hospital mortality (Mantel–Haenszel statistic [MH], 1.06; 95% confidence interval [CI], 0.81–1.38; n=9).

Figure 6

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: 1-year mortality (Mantel–Haenszel statistic [MH], 0.48; 95% confidence interval [CI], 0.27–0.83; n=2).

Figure 7

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: nosocomial pneumonia (Mantel–Haenszel statistic [MH], 1.21; 95% confidence interval [CI], 0.82–1.78; n=4).

Figure 8

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: bleeding complications (Mantel–Haenszel statistic [MH], 3.68; 95% confidence interval [CI] 2.34–5.81; n=3).

Figure 9

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: haemorrhagic stroke (Mantel–Haenszel statistic [MH], 1.00; 95% confidence interval [CI], 0.32–3.08; n=3).

Figure 10

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: continuous renal replacement therapy (Mantel–Haenszel statistic [MH], 1.56; 95% confidence interval [CI], 0.91–2.67; n=4).

Figure 11

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) score (Mantel–Haenszel statistic [MH], 2.70; 95% confidence interval [CI], 2.48–2.93; n=4).

Figure 12

Extracorporeal membrane oxygenation (ECMO) versus conventional mechanical ventilation: Sequential Organ Failure Assessment (SOFA) score (Mantel–Haenszel statistic [MH], 2.56; 95% confidence interval [CI], 2.47–2.65; n=7).