The effect of high PEEP on hemodynamic stability during OLV: a sub-analysis of the PROTHOR Trial.

Abstract

Introduction: During thoracic surgery, one-lung ventilation (OLV) provides a ventilation strategy enabling optimal surgical exposure. However, evidence for optimal mechanical ventilation is scarce. Due to its potential beneficial effect on postoperative pulmonary complications (PPC’s), intraoperative high PEEP (10 cmH2O) with recruitment maneuvers (RM’s) versus low PEEP (5 cm H2O) is compared in the PROTHOR Trial. Higher PEEP is, however, associated with deteriorating intraoperative hemodynamics. This sub-analysis investigates whether higher PEEP in the PROTHOR Trial induces hemodynamic instability (HI) during OLV compared to low PEEP. Methods: Patients eligible for the PROTHOR Trial were included. A validated HI-score including hemodynamic parameters, fluid therapy and cardiovascular medication was used to compare both cohort groups. At the start of OLV (T0) the first HI-score was calculated and every hour consecutively. Analysis was conducted for every timepoint (TX), the mean HI-score and the mean gradient between T0 and the last TX to adjust for different durations of surgery. Results: At the moment of analysis, 33 patients were included of which 32 underwent lung surgery. All included characteristics such as gender, age, weight and ASA-score, total duration of anesthesia and duration of OLV were equally distributed between both groups. No significant variation in HI-score at any individual TX was found; nor for the mean HI-score (P= 0.602) or gradient (P= 0.375). Discussion: In this study, HI in the high PEEP group (10 cmH2O) was comparable to the low PEEP group (5 cmH2O) during OLV in thoracic surgery. However, many factors are still subject for further study and physicians should act with caution when applying PEEP in OLV.