Effect of positive end-expiratory pressure on right heart function in mechanically ventilated patients: An ultrasonography based study

Objective: To investigate the effect of positive end-expiratory pressure (PEEP) on right heart function in mechanically ventilated patients using bedside ultrasonography Design: Retrospective study Setting: Department of Emergency Medicine, the First Affiliated Hospital of Anhui Medical University, Hefei, China Subjects: Eighteen patients who received mechanical ventilation between December 2014 and May 2016 Interventions: Different levels of PEEP were applied to patients to achieve appropriate PaO2 levels. Main outcome measures: Indices of right heart function was assessed at three different PEEP levels, <= 5 cm H2O, 5-10 cm H2O or >= 10 cm H2O. Indices included preload assessment by measurement of the area of the right atrium (RA), the diameter of the inferior vena cava (IVC) and measurement of the central venous pressure (CVP); afterload was assessed by estimation of the pulmonary vessel resistance (PVR); right ventricular systolic function was assessed by tricuspid annular plane systolic excursion (TAPSE). Results: The IVC diameter and the CVP increased as PEEP levels increased (14.5 +/- 2.2 vs. 16.9 +/- 1.4 vs. 22.6 +/- 2.4; 7.1 +/- 1.1 vs. 7.9 +/- 1.3 vs. 13.2 +/- 2.0); the RA area decreased at the same time (36.6 +/- 2.9 vs. 32.1 +/- 2.0 vs. 25.3 +/- 3.8). These changes were statistically significant. PVR and TAPSE changed significantly at higher levels of PEEP (p<0.05). PEEP levels positively correlated with the IVC diameter and the PVR, and negatively correlated with TAPSE; coefficients of determination were 0.644, 0.759, and 0.628, respectively. Conclusions: The application of PEEP decreased the preload and increased the afterload of the right heart. Right ventricular contractility decreased significantly at higher levels of PEEP.