Background: General anesthesia induction with the initiation of positive pressure ventilation creates a vulnerable phase for patients. The impact of positive intrathoracic pressure on cardiac performance has been studied but remains controversial. 3D echocardiography is a valid and MRI-validated bed-side tool to evaluate the right ventricle (RV). The aim of this study was to assess the impact of anesthesia induction (using midazolam, sufentanil and rocuronium, followed by sevoflurane) with positive pressure ventilation (PEEP 5, tidal volume 6 – 8 ml/kg) on 2D and 3D echocardiography derived parameters of RV function.
Methods: A prospective observational study on fifty-three patients undergoing elective cardiac surgery in a tertiary care university hospital was designed. Transthoracic echocardiography exams were performed before and immediately after anesthesia induction and were recorded together with hemodynamic parameters and ventilator settings.
Results: TAPSE as a parameter reflecting the movement of the lateral tricuspid annulus was significantly reduced (mean difference -1.6mm (95% CI -2.6mm to -0.7mm; p=0.0013). Tissue Doppler derived tricuspid annulus peak velocity was also significantly reduced (mean difference -1.9% (95% CI: -2.6 to -1.2; p<0.0001), but global right ventricular ejection fraction (p=0.1607) and right ventricular stroke volume (p=0.1838) did not change.
Conclusions: This data shows a preserved right ventricular ejection fraction and right ventricular stroke volume despite reduced baso-apical right ventricular function after anesthesia induction and initiation of positive pressure ventilation. Because only small changes were seen the clinical impact has yet to be determined.
Trial Registration: Retrospecitvely registered, 6th June 2016, ClinicalTrials.gov Identifier NCT02820727.
Keywords: Right ventricular function; positive-pressure respiration; anesthesiology; echocardiography, three-dimensional.