1998 OPEN FORUM Abstracts
EVALUATION OF A PORTABLE NITRIC OXIDE SYSTEM FOR INTERHOSPITAL TRANSPORT DURING NEONATAL MECHANICAL VENTILATION
Michael Tracy, RRT, Robert L. Chatburn, RRT, Eileen Stork, M.D. University Hospitals of Cleveland, Ohio
BACKGROUND: Rainbow Babies & Children's hospital is a tertiary referral center for ECMO. We frequently transport newborns with persistent pulmonary hypertension to our hospital for medical management and ECMO. Patients who qualify are placed on inhaled nitric oxide therapy (NO) in an attempt to avoid ECMO. Initiating NO at the referring hospital may provide increased stability for transported patients. The purpose of this study was to evaluate a portable NO delivery system that could be used on ventilated neonates. Methods: We designed a system composed of a transport ventilator (Biomed MVP-10), a D cylinder of nitric oxide at 800 ppm (Ohmeda) and a combined NO, NO2 analyzer (Printer Nox, Micro Medical) illustrated below. We selected the Biomed transport ventilator for its compatibility with our transport isolette. The Ohmeda D cylinder was selected for its light weight/small size with 800 ppm concentration to minimize gas consumption. The Printer Nox was selected after an inaccuracy study. This study compared the Printer Nox to a "gold standard" chemiluminescent analyze (ECO physics). Both analyzers were connected to a patient circuit and NO was delivered at 9 concentrations over the range of 1 ppm to 40 ppm. The differences between the two measurements at each level were used to construct an inaccuracy interval (covering 95% of future measurements at the 99% confidence level). The final system was assembled by mounting the analyzer to an autosyringe clamp and rail mounted to the isolette. The NO source tank was mounted in a spare tank slot at the base of the Isolette. The system was evaluated under simulated patient conditions in the transport vehicle. Environmental testing consisted of measuring NO/ NO2 inside the vehicle where passengers would sit, without scavenging ventilator exhaust.
Results: The inaccuracy of Printer Nox measurements was only -1.07 ppm to 0.99 ppm. During simulated use, desired NO levels were steady, ±1 ppm. Environmental test results are shown below (readings of NO/NO2 after stabilization at various distances from ventilator):
Delivered NO 0 cm 40 cm 80 cm 160 cm
20 19.4/0.10 0.75/0.10 0.55/0.10 background
40 38.8/0.17 1.4/0.15 1.05/0.15 0.80/0.15
80 77.3/1.9 1.90/0.19 1.55/0.15 1.10/0.15
EXPERIENCE: The system added little weight and did not impair the ease or speed of loading/unloading or Isolette portability. Conclusions: A simple, practical device can be constructed to safely provide NO to ventilated neonates during transport.
(See Original for Figure)
The 44th International Respiratory Congress Abstracts-On-Disk®, November 7 - 10, 1998, Atlanta, Georgia.