Inhaled nitric oxide (NO) for the treatment of early allograft failure after lung transplantation

Objective: Inhalation of high concentrations of nitric oxide (NO) has been shown to improve gas exchange and to reduce pulmonary vascular resistance i n individuals with ischemia-reperfusion injury following orthotopic lung tr ansplantation. We assessed the cardiopulmonary effects of low doses of NO i n early allograft dysfunction following lung transplantion. Design: Prospective clinical dose-response study. Setting: Anesthesiological intensive care unit of a university hospital. Patients and participants: 8 patients following a single or double lung tra nsplantation who had a mean pulmonary arterial pressure (PAP) in excess of 4.7 kPa (35 mmHg) or an arterial oxygen tension/fractional inspired oxygen ratio (PaO2/FIO2) of less than 13.3 kPa (100 mmHg). Interventions: Gaseous NO was inhaled in increasing concentrations (1, 4 an d 8 parts per million, each for 15 min) via a Siemens Servo 300 ventilator. Measurements and results: Cardiorespiratory parameters were assessed at bas eline, after each concentration of NO, and 15 min after withdrawal of the a gent [statistics: median (25th/75th percentiles Q1/ 03), I:ANOVA, Dunnett's test, p < 0.05]. Inhaled NO resulted in a significant, reversible, dose-de pendent, selective reduction in PAP from 5.5(5.2/6.0) kPa at control to 5.1 (4.7/5.6) kPa at 1 ppm, 4.9(4.3/ 5.3) kPa at 4 ppm, and to 4.7(4.1/ 5.1) kP a at 8 ppm. PaO2 increased from 12.7(10.4/17.1) to 19.2(12.4/ 26.0) kPa at 1 ppm NO, to 23.9(4.67/ 26.7) kPa at 4 ppm NO and to 24.5(11.9/28.7) kPa at 8 ppm NO. All patients responded to NO inhalation (either with PAP or PaO2 ), all were subject to long-term inhalation (1-19 days). All were successfu lly weaned from NO and were discharged from the intensive care unit. Conclusion: The present study demonstrates that low-dose inhaled NO may be an effective drug for symptomatic treatment of hypoxemia and/or pulmonary h ypertension due to allograft dysfunction subsequent to lung transplantation .