The effect of common interventions in the intensive care unit on right ventricular function after cardiac surgery – An intervention study.

Critical care following cardiac surgery is a complex task including both cardiac and pulmonary management strategies because optimal postoperative care is essential for outcome [1]. The effect of such interventions on right ventricular (RV) function has not been sufficiently explored. The aim of this study was to investigate what effect ICU interventions have on RV function. Thirty patients were studied in the ICU following coronary artery bypass graft surgery. Transoesophageal echocardiography (TEE) and a pulmonary artery catheter (PAC) were used to assess hemodynamic variables and echocardiographic measures of RV function. TEE evaluation included RV fractional area change, 3D RV ejection fraction, 3D RV stroke volume and RV global longitudinal strain (RV-GLS). Interventions were done separately and included: Trendelenburg position, PEEP 0, 5 and 10 cm H2O, increased oxygen fraction (100%), and AAI, DDD and VVI pacing. Trendelenburg increased global echocardiographic measures of RV function as well as CO 0.44L*min-1 [95%CI: 0.21;0.67] due to an increased stroke volume (SV). Increasing PEEP from 0 to 10 reduced SV and consequently CO by 0.41L*min-1. Pulmonary vascular resistance (PVR) was not significantly changed by different PEEP levels. AAI or DDD pacing at a heart rate 15 beats above baseline increased CO 0.35L*min-1 [95%CI 0.07;0.63]. In contrast VVI pacing decreased CO by 24% (1.2L*min-1 [95%CI 0.9;1.6]). VVI reduced all RV echocardiographic variables. Applying 100% O2 did not affect PVR or haemodynamic state but RV-GLS was significantly improved -4.4% [95%CI: -6.9; -1.9]. In patients with normal RV function undergoing CABG several routine interventions in the ICU affects RV function significantly, in particular PEEP and VVI pacing which induces clinically important reductions in SV. [ABSTRACT FROM AUTHOR]