A bench study of inhaled nitric oxide delivery during high frequency percussive ventilation

Abstract

Background: Safe and effective delivery of inhaled nitric oxide (INO) requires the appropriate interface of ventilator and INO delivery device.

Methods: We compared INO delivery using four configurations with the Transport Sinusoidal Bronchotron® and INOmax DSIR Plus^® in a lung model. Ventilator settings and lung model values were held constant. Delivered NO, NO₂ , and inspired oxygen (FIO₂ ) were measured. The mean difference between set and measured NO was calculated and compared using ANOVA.

Results: Placement of the injector module in line with the sliding venturi resulted in a ventilator failure. With both continuous flow techniques there was no appreciable NO₂ generated and the mean difference between set NO and measured NO at 20 and 40 ppm was -16.5 ppm and -33.2 ppm at flows of 5 and 10 L/min. Placement of the injector module between the sliding venturi and lung model resulted in an increase of NO2 to a peak of 2.4 ppm (mean 2.3 + 0.1) and a mean difference between set and measured NO of + 11.3 ppm and +30 ppm at 20 and 40 ppm, 300 cycles per minute (cpm), and 22.1 ppm and 37.6 ppm, at 20 and 40 ppm, 600 cpm. None of the test configurations delivered INO within 30% of set concentrations. No alarms or interruption of INO delivery occurred.

Conclusion: The dual gas delivery system of the Bronchotron prevents accurate delivery of INO. The combination of these two devices should be accomplished with caution and vigilance.

Keywords: bench evaluation; high frequency percussive ventilation; high frequency ventilation; inhaled nitric oxide.