Department of Surgery, University of Cincinnati School of Medicine, Cincinnati, OH 45267, USA.
Airman Biosciences Division, Wright Patterson AFB, OH 45433, USA.
Mil Med. 2024 Aug 19;189(Suppl 3):579-584. doi: 10.1093/milmed/usae195.
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.
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.
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.
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.
吸入一氧化氮（INO）是一种选择性肺血管扩张剂，由充满 800ppm 一氧化氮的压缩气体钢瓶输送，这些钢瓶在氮气中以 2,200 磅/平方英寸（137.8 巴）的压力填充。目前，FDA 批准在没有心脏病的情况下，将 INO 用于有低氧血症和肺高血压迹象的足月或近足月婴儿。INO 也已被证明可改善成人难治性低氧血症的氧合作用。由于需要大型压缩气瓶，目前在军事航空医疗运输中禁止使用 NO。我们对 2 种从室气中产生 NO 而无需使用加压气瓶的输送系统进行了台架评估。
我们在地面、8000 英尺（2437 米）和 14000 英尺（4267 米）的模拟高度的海拔室中，对 2 种便携式一氧化氮 INO 生成系统（LungFit PH，Beyond Air Inc，Garden City，NJ 和原型 NO 发生器，Odic Inc， Littleton，MA）进行了评估。每个设备的输出都被注入到连接到测试肺的呼吸机回路的吸气支。使用 731 呼吸机（Zoll Medical，Chelmsford，MA）和 T1（Hamilton Medical，Reno，NV），每个呼吸机设置重复 24 次组合。INOmax DS IR 用于通过连接在呼吸机回路吸气支的取样线测量输送的 INO 和 NO2。快速响应氧分析仪（O2CAP，Oxigraf Inc，Sunnyvale，CA）用于测量吸入 FiO2。目标 INO 浓度为 20 ppm。
在所有呼吸机设置下，LungFit 装置在地面、8000 英尺（2437 米）和 14000 英尺（4267 米）处的 INO 输送量分别为 19.8±1.6 ppm、16.1±1.9 ppm 和 11.6±1.7 ppm。Odic 装置的 INO 剂量分别为 20.6±1.4 ppm、21.3±5.5 ppm 和 20.4±9.1 ppm。
这两种设备在地面上都能提供可靠的 INO 剂量。在 14000 英尺（4267 米）的高度（P<0.01），两种设备的 INO 输送准确性都受到显著影响，在 8000 英尺（2437 米）的高度（P<0.01），LungFit 也受到影响。在 8000 英尺（2437 米）的高度（P>0.05），Odic 设备的 INO 剂量差异没有统计学意义，尽管在选定的呼吸机设置下存在较大差异。通过仔细监测，使用无需加压气瓶的室气生成 INO 的设备可以在航空医疗运输中使用，而无需使用加压气瓶。
