Modern Protective Ventilation Strategies: Impact upon the Right Heart

‘Protective ventilation’ for acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) is a major advance in intensive care medicine. However, components of protective ventilation expose the right heart to challenges. Acute cor pulmonale (ACP), patent foramen ovale (PFO) and right ventricular failure (RVF) are recognised complications that could potentially reduce the benefit of protective ventilation. We sought to determine the rates of ACP, PFO and RVF in critically ill adults undergoing protective ventilation with ARDS/ALI and to identify their impact on mortality and critical illness acuity. A comprehensive search of electronic databases including Medline (OVID, EmBase) and CINAHL (EBSCO) was undertaken, including Cochrane Library and international registries, between January 1991 and December 2011. A systematic review identified a total of 248 articles; 27 were reviewed in full and 22 studies were included. All 22 included studies were observational or quasi-experimental with no randomised, controlled trials available. ACP was present in 16–100%, PFO 1.3–22.0% and RVF 9.6–26.0%. Neither ACP nor PFO was associated with an adverse effect on mortality and ACP seemed reversible in survivors; however both ACP and PFO were associated with prolonged need for ICU support. RVF was variously associated with no increase in mortality to an odds ratio 5.1 for death in multivariate analysis. There was marked heterogeneity in the studies included, explaining the range of observed values. Recommendations for future research and practice were produced. Modern protective ventilation during ARDS has been shown to exert inconsistent effects on the right heart which may be of clinical significance. Further research is needed to determine these effects better