Effects of Positive End-Expiratory Pressure on Pulmonary Oxygenation and Biventricular Function during One-Lung Ventilation: A Randomized Crossover Study

Abstract

Although the application ofpositiveend-expiratorypressure(PEEP) can alter cardiopulmonary physiology duringone-lungventilation(OLV), these changes have not been clearly elucidated. Thisstudyassessed theeffectsof different levels of PEEP onbiventricularfunction, as well aspulmonaryoxygenationduring OLV. Thirty-six lung cancer patients received one PEEP combination of six sequences, consisting of 0 (PEEP_0), 5 (PEEP_5), and 10 cmH2O (PEEP_10), using acrossoverdesign during OLV. The ratio of arterial oxygen partialpressureto inspired oxygen fraction (P/F ratio), systolic and diastolic echocardiographic parameters were measured at 20 min after the first, second, and third PEEP. P/F ratio at PEEP_5 was significantly higher compared to PEEP_0 (p= 0.014), whereas the P/F ratio at PEEP_10 did not show significant differences compared to PEEP_0 or PEEP_5. Left ventricular ejection fraction (LV EF) and right ventricular fractional area change (RV FAC) at PEEP_10 (EF,p< 0.001; FAC,p= 0.001) were significantly lower compared to PEEP_0 or PEEP_5. RV E/E' (p= 0.048) and RV myocardial performance index (p< 0.001) at PEEP_10 were significantly higher than those at PEEP_0 or PEEP_5. In conclusion, increasing PEEP to 10 cmH2O decreasedbiventricularfunction, especially on RVfunction, with no further improvement onoxygenationcompared to PEEP 5 cmH2O during OLV.