Inhaled NO and Sildenafil Combination in Cardiac Surgery Patients with Out-of-Proportion Pulmonary Hypertension: Acute Effects on Post-Operative Gas Exchange and Hemodynamics Matamis et al: iNO and Sildenafil in Cardiac Surgery Patients

Background To examine the effects of co-administration of sildenafil and inhaled nitric oxide (iNO) in patients with out-of-proportion pulmonary hypertension who underwent cardiac valve replacement surgery. Methods and Results Twenty consecutive cardiac surgery patients with out-ofproportion pulmonary hypertension were randomized postoperatively into two groups: group A received 10ppm of iNO followed by sildenafil (100mg) pos 30 min later , and group B received initially sildenafil (100mg) orally followed by 10ppm of iNO 60 min later. Hemodynamic and gas exchange data were obtained at baseline, after administration of either iNO or sildenafil alone and at 90 min from baseline. In group A, iNO resulted in a significant reduction in MPAP and PVRI (by 9.6% and 20.8% respectively). In group B, sildenafil administration also resulted in a significant decrease in MAP, MPAP, PAOP, PVRI, SVRI but also in PO2/FiO2 ratio (by 18.7%, 22.0%, 15.7%, 31.6% 21.3% and 14% respectively). In both groups the co-administration of the two drugs resulted in a significant further reduction of MAP, MPAP, PAOP, SVRI, PVRI, while CI and SvO2 remained unchanged. The hypoxemia after sildenafil administration in group B improved after the co-administration of iNO and thus PO2/FiO2 returned to values towards baseline. Conclusions In this study, the postoperative co-administration of iNO and oral sildenafil in patients with out-of-proportion pulmonary hypertension undergoing cardiac surgery is safe and results in an additive favourable effect on pulmonary arterial pressure and pulmonary vascular resistance, without systemic hypotension and ventilation/perfusion mismatch.