Accurate and precise delivery of nitric oxide during high-frequency oscillatory ventilation.
BACKGROUND
We have previously described a method for the precise delivery of inhaled nitric oxide (iNO) via a conventional, continuous-flow, pressure-limited, time-cycled ventilator. Because of the augmented effect of iNO decreasing pulmonary vascular resistance with high-frequency oscillatory ventilation (HFOV), we developed and bench tested a system that permits easy and accurate iNO delivery during HFOV.


METHODS
The system uses a mass flow controller to deliver fixed volumes of iNO to the HFOV circuit in the range 0 to 20 ppm iNO. The accuracy of the delivery system is based on a comparison of the difference between iNO measured at strategic points in the circuit and the calculated true value.


RESULTS
The mean difference between the measured and calculated value for iNO (n = 360) was -0.2+/-1.74 ppm (2 SD) (range, 0 to 20 ppm, 0 to 15 Hz). The formation of nitrogen dioxide was <1 ppm at the level of the endotracheal tube.


CONCLUSIONS
The method tests the accuracy of iNO measurements and provides an assessment of the uncertainty over the range of iNO and HFOV settings used clinically.
Espinosa
R M
RM
Department of Pediatrics, The Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey 17033, USA.
Marks
K H
KH
D000280:Administration, Inhalation; D001944:Breath Tests; D004867:Equipment Design; D006612:High-Frequency Ventilation / Q000295:instrumentation*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology / Q000628:therapy; D007231:Infant, Newborn; D007442:Intubation, Intratracheal; D009569:Nitric Oxide / Q000008:administration & dosage* / Q000032:analysis; D015203:Reproducibility of Results; D012124:Respiratory Care Units; D014665:Vasodilator Agents / Q000008:administration & dosage*
D014665:Vasodilator Agents; D009569:Nitric Oxide