LIFE-THREATENING EFFECTS OF DISCONTINUING INHALED NITRIC-OXIDE IN SEVERE RESPIRATORY-FAILURE

We present the effects of abrupt discontinuation of inhaled nitric oxi de (NO) in four patients with severe hypoxemic: respiratory failure. T hese patients ranged from 9 mo to 65 yr of age. In each patient, after the initiation of inhaled NO, a marginal, but immediate, beneficial e ffect on gas exchange and, when measured, a reduction in pulmonary art ery pressures was noted. However, during attempts to discontinue inhal ed NO, not only did these patients develop worsening oxygenation and r ecrudescence of pulmonary hypertension but, unexpectedly, these parame ters were worse than the baseline values, leading to life-threatening hemodynamic instability. These effects reversed immediately after rein stitution of inhaled NO. The mechanism of this severe ''rebound'' in p ulmonary hypertension after abrupt withdrawal of NO is unclear, but it s existence emphasizes the need to avoid a substantial risk to these p atients. Moreover, we believe that both unintentional and intentional termination of inhaled NO therapy may lead to life-threatening deterio ration in gas exchange and circulatory hemodynamics that exceeds the i nitial therapeutic benefit.