Outpatient inhaled nitric oxide in a patient with idiopathic pulmonary fibrosis: a bridge to lung transplantation.

Inhaled nitric oxide (INO) has been shown to improve oxygenation and decrease intrapulmonary shunt and pulmonary hypertension in various lung diseases. In this study we report a patient with end-stage idiopathic pulmonary fibrosis and pulmonary hypertension who received INO after coronary artery bypass surgery, with significant improvement in arterial oxygenation and pulmonary arterial pressure. Using a pulsing delivery system, the patient continued to receive outpatient INO for 30 months while waiting for lung transplantation. Exercise study and two-dimensional echocardiogram, after 3 months of inhaled NO, demonstrated continued benefits of INO for improvement of arterial oxygenation, pulmonary arterial pressure and exercise tolerance.

Utility of measurements of oxygen cost of breathing in predicting success or failure in trials of reduced mechanical ventilatory support.

OBJECTIVE: Test whether a change in oxygen consumption produced by a reduction in level of mechanical ventilatory support predicts failure to tolerate the reduction in level of support. DESIGN: Prospective study of the sensitivity and specificity of increased oxygen cost of breathing as a predictor of failure to tolerate a reduction in ventilatory support in patients undergoing weaning, using a protocol that incrementally reduces the level of mechanical ventilatory support. SETTING: University medical center. METHODS: We studied 228 trials in 30 patients who had required mechanical ventilatory support for at least 72 hours and who were being weaned using a standardized protocol that provided for three 30-minute trials of reduced mechanical ventilatory support per day, followed by ventilatory muscle rest. Using a metabolic monitor, we monitored oxygen consumption (V(O(2))) prior to and during 228 incremental reductions in level of mechanical ventilatory support conducted as part of a standardized weaning protocol. Oxygen cost of breathing was defined as the difference in V(O(2)) (Delta V(O(2))) during the trial of reduced mechanical ventilatory support, compared to a 30-minute resting period immediately before the trial. A successful trial was defined as one that could be continued for 30 minutes without development of clinical signs of ventilatory failure. Changes in V(O(2)) and the ratio of respiratory frequency to tidal volume (f/V(T)) during a weaning trial were evaluated as predictors for failure of a 30-minute trial of reduced ventilatory support. RESULTS: A 15% increase in oxygen cost of breathing predicted failure in the trial, with a sensitivity of 96.6%, specificity of 85.7%, positive predictive value of 98.5%, and negative predictive value of 72.0%. Neither change in V(O(2)) measured early in the trial nor f/V(T) proved to be as successful in predicting failure to tolerate an incremental reduction in ventilatory support. CONCLUSION: Change in V(O(2)) following an incremental reduction in level of mechanical ventilatory support may be a useful predictor for determining which patients will rapidly fail to tolerate that level of reduction.