Inhaled nitric oxide (INO) acts as a pulmonary vasodilator and has been FDA approved for hypoxic respiratory failure of the term and near term neonate. By lowering pulmonary vascular resistance, INO would be of potential benefit in patients with severe right ventricular dysfunction. This report describes the largest series in the literature on the effects of INO in adult postoperative cardiac patients with right ventricular failure.
Patients were considered eligible for inhaled nitric oxide therapy if they were > 18 years of age, were post cardiac surgery, had moderate to severe right ventricular dysfunction by echocardiography, had a PAOP > 18 mmHg or RVEDV > 120 ml/m2, PVR > 200 dynes/sec and were unresponsive or intolerant to maximal pharmacotherapy. Nitric oxide was initiated at 5 ppm and increased until maximal benefit was observed (maximum dose 80 ppm). Outcomes measured included oxygenation and hemodynamic variables, dose and duration of therapy, and mortality.
Between March 1998 and October 2004, 97 patients received INO therapy. 40 (41%) patients survived to discharge from hospital. 57 (59%) died before discharge from hospital. Mean INO dose was 48 ppm for the survivors and 53 ppm for non-survivors. Hemodynamic parameters in all groups are shown in the Table.
Our experience has shown that INO does decrease PVR and improve both CI and REF in patients with severe right ventricular dysfunction who have proven refractory to maximal pharmacotherapy. Our experience shows improved right heart hemodynamics. Using Receiver Operating Characteristic Curve, a CI of 2.5 discriminates survivors and non-survivors, however with low sensitivity (62.5) and specificity (66.7).
INO can be effectively used to improve right heart function in postoperative cardiac surgical patients who did not respond to maximal pharmacotherapy. It is a useful adjunctive therapy in lieu of right ventricular assist devices in such patients.
Rammohan Marla, None.