The Science Journal of the American Association for Respiratory Care

2004 OPEN FORUM Abstracts

DELIVERY OF INHALED NITRIC OXIDE (iNO) VIA HIGH FREQUENCY JET VENTILATION (HFJV), A BENCH STUDY Richard M. Hoskins RRT C-CPT CPFT

Christus St Joseph Hospital NICU, Houston Texas

Background: A few papers have been published describing the technical aspects of the delivery of iNO with HFJV: iNOTherapeutics has described in their technical bulletin of not approving the use of iNO with HFJV.
Most papers have described the method of placing the iNO Injector upstream of the humidifier of the Bunnell Life Pulse HFJV(Bunnell Inc), and using the HFJV as the primary ventilation source. We undertook a bench study to determine if iNO can reliably be delivered from the conventional ventilator (CV) side of the patient circuit.

Methods: As described by Platt et al (Journal of Perinatology 2003; 28:387-391, & personal communication) iNO was delivered using an iNOVent system (iNOTherapeutics) a Bunnell HFJV, and a Sechrist IV 100B ventilator (Sechrist Industries). The injector module was placed in the conventional position proximal to the CV heated humidifier (Fisher-Paykel model 730) and the remainder of the configuration is as described in the iNOThereapeutics Operators manual. A 3.5 Hi/Jo Jet ETT (Mallinckodt) was used to provide proximal and distal sampling ports, a dual infant lung model was constructed using dual infant calibration lungs. The dual infant lung model was constructed to provide a compliance of 1.4 ml/cmH2O. The Sechrist was used at IMV rates of 2, 5, and 10 cycles per minute, and in the CPAP mode. Gas flow of the CV was between 6-8 LPM, per our usual clinical practice on infants > 35 week gestation. iNO was measured at the proximal and distal ports of the Hi/Lo Jet ETT, and at the proximal position as described in the iNOVent manual, using dual iNOVent systems, to provide simultaneous observations of measured parameters. All measurements were repeated by reversing the positions of the INOVents, to qualify the iNOVent monitor systems. Both iNOVents were calibrated prior to the study per the operators manual.

Results: Measured iNO (ppm) was within 1-2 ppm of the recommended proximal sampling site, as measured in the ETT proximal and distal sampling sites. Nitrogen dioxide (NO2) never exceeded 0.8% in all ventilation modes. In the CV modes, NO2 remained in the 0.1-0.4 % range, only when the CV was in the CPAP mode, with the flow at 6 lpm did the NO2 approach 0.8%.

Conclusions: In our model, we determined that iNO can be safely delivered on the CV side of the patient circuit, allowing that we used higher flows than previously described. Continued investigation will determine if this method will be acceptable clinical practice in other facilities.

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