The Effect of Common Interventions in the Intensive Care Unit on Right Ventricular Function After Cardiac Surgery-An Intervention Study

Objective: Critical care therapy after cardiac surgery includes interventions to aid pulmonary and cardiac function. The aim of this study was to investigate the effect of such interventions on right ventricular function (RVF).

Design: This was a prospective intervention study.

Setting: This study was conducted at a single tertiary university hospital.

Participants: Thirty elective coronary artery bypass graft (CABG) patients were studied in the intensive care unit (ICU) following CABG surgery.

Interventions: The following interventions were investigated: Trendelenburg position; positive end-expiratory pressure (PEEP) 0, 5, and 10 cmH₂O; increased oxygen fraction; and AAI, DDD, and VVI pacing.

Measurements and main results: Transesophageal echocardiography and a pulmonary artery catheter were used to assess hemodynamics and RVF. Transesophageal echocardiography measures included right ventricular (RV) fractional area change, RV ejection fraction, RV stroke volume (SV), and RV global longitudinal strain (RV-GLS). Trendelenburg increased global echocardiographic measures of RVF as well as cardiac output (CO) 0.44 L/min (95% CI: 0.21-0.67). Increasing PEEP from 0 to 10 reduced SV and consequently CO by 0.41 L/min. Pulmonary vascular resistance was not changed by increasing PEEP. AAI or DDD pacing (15 beats above baseline) increased CO 0.35 L/min (95% CI 0.07-0.63). In contrast VVI pacing decreased CO by 24% (1.2 L/min [95% CI 0.9-1.6]). Applying 100% O₂ did not affect hemodynamics, but RV-GLS was improved -4.4% (95% CI: -6.9 to -1.9).

Conclusion: In patients with normal RVF undergoing CABG, several routine interventions in the ICU affect RVF, in particular PEEP and VVI pacing, which induces clinically important reductions in stroke volume.