The Science Journal of the American Association for Respiratory Care
Background The utilization of the INOvent (Ohmeda Inc) for in-house transport of nitric oxide (NO) dependent adult patients is most efficient and compatible with a portable transport ventilator. In the absence of a suitable transport ventilator, the INOvent can provide manual delivery of inhaled nitric oxide (INO) at a fixed concentration of 20 ppm via a pneumatic delivery system, or at a variable concentration with the injector module in-line with a manual resuscitation bag. This in vitro study investigated the performance of three adult manual resuscitation bag designs and their performance with two manual inhaled nitric oxide delivery configurations from the INOvent. Methods Open reservoir (PMR 2), closed reservoir (AMBU), and Jackson-Rees design bags were configured with both manual and injector module configurations. Manual bagging was performed through an Dual Adult TTL test lung with PneuView monitoring software (Michigan Instruments) to provide reproducible data from 10 and 20 L/min bagging scenarios.
Results 1. Fixed concentration of 20 ppm INO via pneumatic delivery system: With a maximum flow output from the INOvent manual outiet at 23 L/min, Jackson-Rees and closed reservoir (AMBU) bag performance delivered INO values within 1ppm at 10 and 20 L/min. Open reservoir (PMR 2) design showed a progressive inefficiency as minute ventilation increased.
At 10 L/min bagging: mean Fi02 = 0.90 and NO= 15ppm At 20 L/min bagging: mean Fi02 = 0.85 and NO= 14ppm
2. Variable INO concentration via injector delivery system: With a 15 L/min maximum flow output from an ?e? cylinder Bourdon gauge, Jackson-Rees and closed reservoir (AMBU) bag performance provided delivered INO values (5, 10,20) within 1ppm during 10L/min bagging. The 20 L/min bagging scenario caused a decreased FiO2 (0.95) with the AMBU bag, while maintaining accurate INO levels. Jackson-Rees bag design failed secondary to inadequate flow. Open reservoir (PMR 2) design allowed significant FiO2 (0.78) and INO deficits as previously described. Conclusions Optimal transport utilization of the INOvent is uncomplicated with a transport ventilator. In-line injector module configuration with a manual resuscitation bag provides the next best alternative with O2 delivered via a Thorpe tube flowmeter, instead of a restricted Bourdon guage flowmeter, to the NO injector. Closed reservoir bags provide the most consistent O2/NO delivery with this technique. Jackson-Rees design bags deliver high FiO2 and accurate INO levels but remain source flow dependent. Open reservoir manual resuscitation bags perform poorly when VE delivery increases or source flow is inadequate.
(See Original for Figures)