1998 OPEN FORUM Abstracts
INO THERAPY IN ADULT RESPIRATORY DISTRESS SYNDROME
The movement of inhaled nitric oxide from the laboratory to the bedside has occurred in rapid fashion. The physiologic effects of INO in acute respiratory distress syndrome (ARDS) and pulmonary hypertension are well known. A recent multi-center, placebo-controlled, randomized adult trial has been completed. Results of that trial are patiently awaited. Preliminary results from this trail and issues related to trial design will be discussed.
Multiple investigators have reported a positive response to INO in over half of patients with ARDS at doses < 10 ppm. Positive response is defined as an increase in PaO2/FIO2 of > 20%. In patients with ARDS due to sepsis, positive response is seen in only one-third of patients.
Current research has failed to provide conclusive data which allows the clinician to predict which patients will respond to INO. Positive response has been associated with elevated cardiac output, increased pulmonary artery pressures, and low initial PaO2/FIO2. Additionally, patients who demonstrate a positive response to PEEP (alveolar recruitment and improvement in lung compliance) appear to have an improved chance of a positive response to INO.
The positive response to INO appears to last for a short period of time in some patients ( < 48 hrs), while others respond positively for weeks. This phenomena is not well understood.
Complications of INO are relatively minor and easily controlled. Methemeglobinemia has been reported, but only at high doses (>60 ppm). Nitrogen dioxide production can be limited by use of low NO doses and an appropriate NO delivery device. Prolonged toxicity of low doses remains unknown.
Current research continues to look for methods of predicting a positive INO response, optimal dosing, and potential long term toxicity.
The 44th International Respiratory Congress Abstracts-On-Disk®, November 7 - 10, 1998, Atlanta, Georgia.