Nitric oxide inhalation prompts weaning from the right ventricular assist device: evaluation under continuous-flow biventricular assistance.

Objective: The objective of this study was to investigate the effect of nitric oxide on the recovery of right heart function under global ischemia with a continuous-flow biventricular assist device support.

Methods: Fifteen piglets were divided into three groups: continuous-flow biventricular assist support only (control group), global ischemia with continuous-flow biventricular assist support (ischemia only group), and global ischemia with continuous-flow biventricular assist support plus nitric oxide inhalation (nitric oxide group). Two continuous-flow pumps were used as left and right ventricular assist devices. In the ischemic groups (ischemia only group and nitric oxide group), global ischemia was induced for 30 minutes and followed by a 6-hour reperfusion period; the nonischemic control group underwent a 6-hour perfusion period only. The left ventricular assist device was driven at a flow rate of more than 75 to 80 mL/(min. kg). The right ventricular assist device was driven so as to sustain the left ventricular assist device flow, and the animal was weaned from it in accordance with the objective of cardiac recovery.

Results: Mean pulmonary arterial pressure remained low in the nitric oxide group (mean 23 mm Hg), whereas it rose from 19.9 mm Hg to 39.3 mm Hg in the ischemia group and to 26.2 mm Hg in the control group. Mixed venous saturation was maintained at more than 60% in all cases. Although no piglets in the ischemia group were able to survive without continuous-flow biventricular assist support, the right ventricular assist device flow ratio (device flow/total systemic flow) in the nitric oxide group could be reduced in all cases, and it was possible to wean the piglets from right ventricular assist device support in 4 of 5 cases.

Conclusion: Inhalation of 40-ppm nitric oxide enabled smoother maintenance of the left ventricular assist device flow and prompted the weaning from right ventricular assist device support on continuous-flow biventricular assist.