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.