Chest
Volume 109, Issue 6, June 1996, Pages 1545-1549
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Clinical Investigations: Nitric Oxide
Pulsed Delivery of Inhaled Nitric Oxide to Patients With Primary Pulmonary Hypertension: An Ambulatory Delivery System and Initial Clinical Tests

https://doi.org/10.1378/chest.109.6.1545Get rights and content

Background

Inhaled nitric oxide (NO) has been shown to be a selective pulmonary vasodilator in certain patients with primary pulmonary hypertension (PPH).

Objectives

The purpose of this study was to design and test a system for delivery of NO to awaken, ambulatory patients with PPH and to evaluate this system in the home setting.

Methods

The ambulatory delivery system consisted of a tank of 80 ppm of NO (balance N2), a modified gas-pulsing device, and nasal cannulas. The pulsing device was set to deliver NO for 0.1 s at the beginning of each inspiration.

Results

Using this system, eight patients with PPH were studied with pulmonary artery catheters in place. Inhalation of NO led to significant reductions in both mean pulmonary arterial pressure (PAPm) (51±12 to 43±10 mm Hg; p=0.001) and pulmonary vascular resistance (PVR) (790±285 to 620±208 dyne·s·cm−5; p=0.01). Three of the eight patients had both greater than 20% and greater than 30% decreases in PAPm and PVR, respectively. No exhaled NO or NO2 was detectable in any of the eight patients. One patient was discharged home from the hospital on a regimen of inhaled NO. At 9 months, no adverse effects were noted and the system was working well.

Conclusions

Pulsed delivery of inhaled NO to ambulatory patients with PPH, via nasal prongs, is feasible and, in some patients, leads to significant improvement in pulmonary hypertension. Inhaled 09NO, therefore, may have a role in the long-term treatment of patients with PPH.

Section snippets

MATERIALS AND METHODS

This study was approved by the Institutional Human Subjects Committee. Informed consent was obtained from the patients.

Delivery and Monitoring

The delivery device functioned without problems. NO was delivered with each breath. Neither NO nor NO2 was detected in the expired gas or ambient air.

The ambulatory patient had no difficulty with the portable system and was able to ambulate in the halls, eat, and bathe. This patient was discharged home from the hospital with an ambulatory system. Large, stationary tanks and small, portable tanks of NO were used to provide continuous NO inhalation.

Hemodynamic and Gas Exchange Results

Hemodynamic data at baseline and 15 min into NO

DISCUSSION

In this study, we have reported details of an NO delivery system that is practical for ambulatory patients. We have demonstrated the reliability of this system in the clinical setting. Finally, we have demonstrated safety and feasibility of the system in eight patients with PPH and, in three patients, we have demonstrated marked reduction in PAPm and PVR with very short NO pulses. One patient was discharged home from the hospital on a regimen of inhaled NO delivered via this system and is

ACKNOWLEDGMENTS

The authors thank Diane McIntyre and Katie Kinninger for their technical assistance in this study.

REFERENCES (16)

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This study was supported, in part, by Nellcor Puritan Bennett Corporation, Pleasanton, Calif, and Apria Healthcare.

revision accepted November 3.

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