ABSTRACT
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 6âcmH2O of positive end-expiratory pressure (PEEP; group C, nâ=â20) or standard ventilation with a recruitment manoeuvre and 10âcmH2O of PEEP after surgery (group RM, nâ=â20). RV function, left ventricular cardiac index (CI) and lung aeration were assessed by transoesophageal echocardiography (TOE) before, at the end of surgery and 30âmin 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 2.9â±â1.1 to 2.6â±â0.9âl min m in group C (Pâ=â0.24) and from 2.8â±â1.0 to 2.6â±â0.8âl min m in group RM (Pâ=â0.32). 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 Pâ=â0.16). Atelectasis was present in 18 patients in group C and 19 patients in group RM (Pâ=â0.88). After surgery, CI decreased further from 2.6 to 2.4âl min m in group C (Pâ=â0.17) but increased from 2.6 to 3.7âl min m in group RM (Pâ<â0.001). TOE-derived RV function parameters improved only in group RM (Hotelling t-test Pâ<â0.001). Atelectasis was present in 100% of patients in group C but only in 10% of those in group RM (Pâ<â0.001). CONCLUSION: Atelectasis after CPB impairs RV function but this can be resolved by lung recruitment using 10âcmH2O of PEEP. TRIAL REGISTRATION: Protocol started on October 2014.