Positive end-expiratory pressure and recruitment maneuvers during one-lung ventilation: A systematic review and meta-analysis

Background It is unclear how positive end-expiratory pressure (PEEP) and recruitment maneuvers impact patients during one-lung ventilation (OLV). We conducted a systematic review and meta-analysis of the effect of lung recruitment and PEEP on ventilation and oxygenation during OLV. Methods A systematic review and random-effects meta-analysis were performed. Mean difference with standard deviation was calculated. Included studies were evaluated for quality and risk of bias using the Cochrane Risk of Bias tool and the modified Newcastle-Ottawa Score where appropriate. Results In total, 926 articles were identified, of which 16 were included in meta-analysis. Recruitment maneuvers increased arterial oxygen tension (PaO2) by 82 mm Hg [20, 144 mm Hg] and reduced dead-space by 5.9% [3.8, 8.0%]. PEEP increased PaO2 by 30.3 mm Hg [11.9, 48.6 mm Hg]. Subgroup analysis showed a significant increase in PaO2 (P = .0003; +35.4 mm Hg [16.2, 54.5 mm Hg]) with PEEP compared with no PEEP but no such difference in comparisons with PEEP-treated controls. No significant difference in PaO2 was observed between “high” and “low” PEEP-treated subgroups (P = .29). No significant improvement in PaO2 was observed for subgroups coadministered PEEP, lung recruitment, and low tidal volumes. PEEP was associated with a modest but statistically significant increase in compliance (P = .03; 4.33 mL/cmH2O [0.33, 8.32]). High risk of bias was identified in the majority of studies. Considerable heterogeneity was observed. Conclusions Recruitment maneuvers and PEEP have physiologic advantages during OLV. The optimal use of PEEP is yet to be determined. The evidence is limited by heavy use of surrogate outcomes. Future studies with clinical outcomes are necessary to determine the impact of recruitment maneuvers and PEEP during OLV.