Impact of Inhalation of Nitric Oxide and Extubation on Hemodynamics of Right Heart in Acute Phase after Left Ventricular Assist Device Implantation

Abstract

Right ventricular failure (RVF) is one of the major complications after LVAD implantation. In acute phase after LVAD implantation, inhalation of nitric oxide (NO) and mechanical respiratory support and extubation causes hemodynamic changes on right heart dramatically. Although perioperative management is crucial to prevent RVF, there was no study which analyzed the impact of NO, mechanical respiratory support and extubation on hemodynamics of right heart in detail. Between December 2014 and September 2018, consecutive 102 patients underwent LVADs implantation in Osaka University Hospital. Patients below 18 years were excluded. Patients with right ventricular assist device support, and/or tracheostomy without trying of extubation after LVAD implantation were also excluded. Finally, 75 patients were included in this study (mean age, 45 ± 14 years; 30% were women). We used 5 different types of LVADs. We assessed the perioperative course of central venous pressure (CVP), pulmonary vascular resistance (PVR), and cardiac index (CI) before and after discontinuation of NO and extubation. Mean duration of NO inhalation was 2.0(0-3.3) days and final concentration of NO was 5ppm. The changes of CVP and CI before and after discontinuation of NO were not significantly (CVP: 10.0±2.7 to 10±2.7 mmHg, p=0.436, CI: 2.8±0.6 to 2.6±0.4 l/min/m2, p=0.999). Mean duration of intubation was 2.7(1.8-6.2) days. Just before extubation, respiratory rate was 17±4rpm and PaO2/FiO2 ratio was 341±71 under 5 cmH20 of positive end-expiratory pressure. The changes of CVP, PVR and CI before and after extubation were significantly (CVP: 9.1±2.9 to 8.2±3.0 mmHg, p=0.001, PVR: 1.1±0.4 to 1.2±0.5 wood, p=0.014, CI: 2.8±0.6 to 3.0±0.6 l/min/m2, p=0.004). Furthermore, patients with elevated CVP(≧10mmHg, n=31) also increased their CI significantly after extubation (CI:2.9±0.5 to 3.1±0.6 l/min/m2, p=0.007). Among adult patients with LVAD, discontinuation of NO inhalation caused minor decrease of CI but not significant. Extubation improves CI even patients with elevated CVP, who are higher risk for suffering from RVF. These analysis of hemodynamic changes imply that after respiratory condition become stable, extubation could be one important choice to improve hemodynamics even in patients with higher risk for RVF.