Inhaled nitric oxide in neonatal and paediatric transport

Evaluation of Inhaled Nitric Oxide Generation Systems at Altitude

INTRODUCTION

Inhaled nitric oxide (INO) is a selective pulmonary vasodilator delivered from compressed gas cylinders filled to 2,200 psig (137.8 bar) with 800 ppm of NO in a balance of nitrogen. NO is currently FDA-approved for use in term or near-term infants with hypoxemia and signs of pulmonary hypertension in the absence of cardiac disease. INO has also been shown to improve oxygenation in adults with refractory hypoxemia. Current doctrine precludes the use of NO during military aeromedical transport owing to the requirement for large compressed gas cylinders. We performed a bench evaluation of 2 delivery systems that create NO from room air without the need for pressurized cylinders.

MATERIALS AND METHODS

We evaluated 2 portable nitric oxide INO generation systems (LungFit PH, Beyond Air Inc, Garden City, NJ and a prototype NO generator, Odic Inc, Littleton, MA) at ground level, 8,000, and 14,000 feet (2,437 and 4,267 meter) simulated altitude in an altitude chamber. The output from each device was injected into the inspiratory limb of the ventilator circuit that was attached to a test lung. A 731 ventilator (Zoll Medical, Chelmsford, MA) and T1 (Hamilton Medical, Reno, NV) were used employing 24 combinations of ventilator settings each repeated in duplicate. An INOmax DS IR was used to measure delivered INO and NO2 via a sampling line attached in the ventilator circuit inspiratory limb. A fast response oxygen analyzer (O2CAP, Oxigraf Inc, Sunnyvale, CA) was used to measure inspired FiO2. Target INO concentration was 20 ppm.

RESULTS

Across all ventilator settings, the LungFit device delivered INO was 19.8 ± 1.6 ppm, 16.1 ± 1.9 ppm, and 11.6 ± 1.7 ppm at ground level, 8,000 ft (2,437 meter), and 14,000 ft (4,267 meter), respectively. The Odic device delivered INO dose was 20.6 ± 1.4 ppm, 21.3 ± 5.5 ppm, and 20.4 ± 9.1 ppm at ground level, 8,000 ft (2,437 meter), and 14,000 ft (4,267 meter), respectively.

CONCLUSIONS

Both devices delivered a reliable INO dose at ground level. Altitude significantly affected INO delivery accuracy at 14,000 ft (4,267 meter) (P < 0.01) with both devices and at 8,000 ft (2,437 meter) (P < 0.01) with LungFit. Differences in INO dosage were not statistically significant with the Odic device at 8,000 ft (2,437 meter)(P > 0.05) although there were large variations with selected ventilator settings. With careful monitoring, devices creating INO from room air without cylinders could be used during aeromedical transport without the need for pressurized cylinders.

Fifty Years of Progress in Neonatal and Maternal Transport for Specialty Care

Specialty care for preterm and critically ill infants has evolved over many years. Neonatal intensive care nurseries were developed, and physicians and nurses learned how to provide intensive care for these infants. Neonatal and maternal (in utero) transport to tertiary centers became common in regionalized systems of care to facilitate the specialized care of high-risk neonates when childbirth occurred in settings without specialized personnel or equipment. Annually, nearly 70,000 neonatal transports occur in the United States. Although specialty care helps reduce rates of neonatal mortality, racial disparities and disparities between urban and rural areas exist. The purpose of this article is to review the progress achieved in neonatal and maternal transport over the past 50 years. The knowledge developed can be used to improve the care provided to women, their fetuses, and infants.

A bench study of inhaled nitric oxide delivery during high frequency percussive ventilation

BACKGROUND

Safe and effective delivery of inhaled nitric oxide (INO) requires the appropriate interface of ventilator and INO delivery device.

METHODS

We compared INO delivery using four configurations with the Transport Sinusoidal Bronchotron® and INOmax DSIR Plus^® in a lung model. Ventilator settings and lung model values were held constant. Delivered NO, NO₂ , and inspired oxygen (FIO₂ ) were measured. The mean difference between set and measured NO was calculated and compared using ANOVA.

RESULTS

Placement of the injector module in line with the sliding venturi resulted in a ventilator failure. With both continuous flow techniques there was no appreciable NO₂ generated and the mean difference between set NO and measured NO at 20 and 40 ppm was -16.5 ppm and -33.2 ppm at flows of 5 and 10 L/min. Placement of the injector module between the sliding venturi and lung model resulted in an increase of NO2 to a peak of 2.4 ppm (mean 2.3 + 0.1) and a mean difference between set and measured NO of + 11.3 ppm and +30 ppm at 20 and 40 ppm, 300 cycles per minute (cpm), and 22.1 ppm and 37.6 ppm, at 20 and 40 ppm, 600 cpm. None of the test configurations delivered INO within 30% of set concentrations. No alarms or interruption of INO delivery occurred.

CONCLUSION

The dual gas delivery system of the Bronchotron prevents accurate delivery of INO. The combination of these two devices should be accomplished with caution and vigilance.

Stabilisation and Transport of the Critically Ill Child

Since the Department of Health Report ‘Paediatric Intensive Care: A framework for the future’ in 1997, paediatric intensive care services have been centralised and 24-hour retrieval services developed. However, all hospitals admitting critically ill children must be able to resuscitate and stabilise prior to retrieval, and occasionally undertake the ‘time-critical’ transfers themselves. This article reviews the clinical and organisational skills involved in the retrieval process, and also suggests ways in which knowledge and skills can be maintained.