The Science Journal of the American Association for Respiratory Care

1999 OPEN FORUM Abstracts

OXYGENATION RESPONSE TO INHALED NITRIC OXIDE (INO) WHEN COMBINED WITH HIGH FREQUENCY OSCILLATORY VENTILATION (HFOV) IN ADULTS.

R. MacDonald RRT, T. Stewart MD, D. Banayan, S. Lapinsky MD, M. Aubin RRT, S. Mehta MD. Mount Sinai Hospital, University of Toronto, Toronto, Canada.

During conventional mechanical ventilation (CMV) approximately 40 - 50% of patients with ARDS respond to INO. However as reported by Rouby et al, the response to INO is augmented when the lungs are optimally recruited (ref.). Since High Frequency Oscillatory Ventilation (HFOV) in adults may be an optimal way to recruit the lungs we speculate that when INO is combined with HFOV the response rate may be improved. We evaluated the acute effect of INO on oxygenation in 6 adults (5F, IM, age 42 ± 19 yrs, APACHE II 29 ± 4) with ARDS while receiving HFOV. Parameters on CMV prior to HFOV: PaO2/FiO2 87 ± 40 mmHg, mean airway pressure (Paw) 27 ± 4 cm H2O, oxygenation index [OI=(FiO2*Paw*100)/PaO2] 45±29. Once patients were stabilized on HFOV (PaO2/FiO2 82 mmHg, Paw 35±4 cmH2O, OI 45±16), INO was initiated at a dose of 14 ± 5 ppm and then titrated to 12 ± 8 ppm over 24 hours. We present PaO2/FiO2 ratios and OI during CMV, HFOV, and during the first 24 hrs of INO. Observations are grouped in intervals of elapsed time 0.3 - 3 hrs and 12 - 24 hrs. Patients were ventilated with HFOV for 34 ± 51 hrs prior to instituting INO. (All values mean ± SD).

All 6 patients showed a ³20% improvement in PaO2/FiO2 during INO, and a ³ 18% improvement in OI. The average improvement in PaO2/FiO2 was 85%, and in OI was 42%. In conclusion, in these patients, INO delivered with HFOV had beneficial physiological effects. Further prospective evaluation is required.

Ref: Puybasset L, Rouby JJ, et al. Factors influencing cardiopulmonary effects of inhaled nitric oxide in acute respiratory failure. Am J Resp Crit Care Med 1995; 152:318-28

(See Original for Figure)

OF-99-232

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