Lung recruitment improves right ventricular performance after cardiopulmonary bypass: A randomised controlled trial.

Background: Atelectasis after cardiopulmonary bypass (CPB) can affect right ventricular (RV) performance by increasing its outflow impedance.

Objective: The aim of this study was to determine whether a lung recruitment manoeuvre improves RV function by re-aerating the lung after CPB.

Design: Randomised controlled study.

Setting: Single-institution study, community hospital, Córdoba, Argentina.

Patients: Forty anaesthetised patients with New York Heart Association class I or II, preoperative left ventricular ejection fraction at least 50% and Euroscore 6 or less scheduled for cardiac surgery with CPB.

Interventions: Patients were assigned to receive either standard ventilation with 6 cmH2O of positive end-expiratory pressure (PEEP; group C, n = 20) or standard ventilation with a recruitment manoeuvre and 10 cmH2O of PEEP after surgery (group RM, n = 20). RV function, left ventricular cardiac index (CI) and lung aeration were assessed by transoesophageal echocardiography (TOE) before, at the end of surgery and 30 min after surgery.

Main Outcome Measures: RV function parameters and atelectasis assessed by TOE.

Results: Haemodynamic data and atelectasis were similar between groups before surgery. At the end of surgery, CI had decreased from 2.9 ± 1.1 to 2.6 ± 0.9 l min m in group C (P = 0.24) and from 2.8 ± 1.0 to 2.6 ± 0.8 l min m in group RM (P = 0.32). TOE-derived RV function parameters confirmed a mild decrease in RV performance in 95% of patients, without significant differences between groups (multivariate Hotelling t-test P = 0.16). Atelectasis was present in 18 patients in group C and 19 patients in group RM (P = 0.88). After surgery, CI decreased further from 2.6 to 2.4 l min m in group C (P = 0.17) but increased from 2.6 to 3.7 l min m in group RM (P < 0.001). TOE-derived RV function parameters improved only in group RM (Hotelling t-test P < 0.001). Atelectasis was present in 100% of patients in group C but only in 10% of those in group RM (P < 0.001).

Conclusion: Atelectasis after CPB impairs RV function but this can be resolved by lung recruitment using 10 cmH2O of PEEP.

Trial Registration: Protocol started on October 2014.