2004 OPEN FORUM Abstracts
THE iNOVENT INJECTOR IN HIGH FREQUENCY JET VENTILATION, A BENCH STUDY.
Richard M. Hoskins RRT C-CPT CPFT Christus St Joseph Hospital NICU, Houston Texas
Background:
Very few references are available on the safe and efficacious
use of Inhaled Nitric Oxide (iNO) with High Frequency Jet Ventilation
(HFJV) iNOthereapueutics has described in their technical bulletin
that the use of the iNOVent (INOTherapeutics) is not approved for use
with the Bunnell Life Port HFJV (Bunnell Inc) due to some cases in
that the jet servo pressure may exceed 6 PSI, which is beyond the
safe operating pressure for the iNOVent Injector module. Platt
et al, has described a method of using the iNOVent Injector with HFJV
(J.of Perinatology 2003; 28:287-291, and personal communication) in
that the injector module is placed proximal to the humidification
module of the HFJV, for more accurate delivery of iNO.
Study
Question: Can the iNOVent Injector module be used with the
Bunnell HFJV without exceeding the operational pressures of the
injector as outlined by the iNOVent Operators Manual?
Method:
A HFJV/ iNO system was constructed as outlined in the study
described by
Platt et al, using an iNOVent system, a Bunnell HFJV, and a Sechrist
IV 100B Infant Ventilator. An RT-200 Calibration Analyzer (Timeter
Corp) was used to verify the pressures observed in the iNOVent
Injector. The injector was inserted in the Gas Out line proximal to
the Humidifier module of the HFJV, Two 4.5 mm ETT adapters and a
22mm/15mm adapter was used to connect the HFJV Gas Out tubing to the
Injector module. Various ventilatory scenarios
of PIP and PEEP, and with and without Conventional Ventilation (CV)
breaths. Compliance of the test lungs was also changed to determine
if increased resistance would increase the Servo Pressure, and
thereby increase the pressures in the Injector Module. Observation
of the pressures obtained by the RT-200, compared to the pressures
displayed on the Servo Pressure displayed on the HFJV was noted.
That the Servo Pressures reflect the actual pressures in the Gas Out
line, was confirmed in communication with the technical support of
Bunnell Inc. (D.Platt, personal communication) Ventilatory scenarios
were set for our patient population. (urban level III NICU) using
observed data from previous patient
records. In our level III NICU, we have not observed instances of
the servo pressureexceeding 5 PSI, in our patient population.
Conclusion:
In this bench study we have observed that the Servo Pressure as
displayed on the Bunnell HFJV closely correlates
with measured pressures within the Gas Out line proximal to the HFJV
humidifier. We have concluded that the application of iNO with HFJV,
as described by Platt et al, can be administered without violating
the operating parameters as outlined by iNOTherapeutics in their
Technical Bulletin, as long as the Servo Pressure is monitored and
remains below 6 PSI. We have not attempted to test this system in a
larger or pediatric population model.