Borland C, Cox Y, Higenbottam T
Department of Respiratory Physiology, Papworth Hospital, Cambridge, UK.
Thorax. 1996 Aug;51(8):855-6. doi: 10.1136/thx.51.8.855.
Unexplained or primary pulmonary hypertension results in an obliteration and obstruction of resistance pulmonary arteries. In these patients gas exchange is impaired and the measurement of gas transfer for carbon monoxide is usually reduced. This has been thought to represent a reduction in pulmonary alveolar capillary blood volume (Vc). A single breath test, measuring simultaneously the uptake of both nitric oxide (NO) and carbon monoxide (CO), provides a simple and practical measurement of membrane diffusion (Dm) and Vc.
A standard single breath test for the measurement of gas transfer for carbon monoxide (TLCO) was adapted to include NO (40 ppm) in the inhaled gas mixture and a breath-hold time at total lung capacity of 7.5 seconds was used. Twelve patients with primary pulmonary hypertension and 10 similar normal volunteers were studied while seated at rest.
The patients had reduced values for TLCO and TLNO. The mean (SD) value of Dm in the patients was 36.7 (32.1) mmol/min.kPa compared with 52.8 (23.9) mmol/min.kPa in the normal subjects. Vc in the patients was 0.03 (0.03) 1 and 0.06 (0.01) 1 in the normal subjects.
The simultaneous measurement of NO and CO uptake is possible in healthy volunteers and patients with primary hypertension. In these patients capillary blood volume is reduced compared with normal subjects.
不明原因或原发性肺动脉高压导致肺阻力动脉闭塞和阻塞。在这些患者中，气体交换受损，一氧化碳气体转移的测量值通常降低。这被认为代表肺泡毛细血管血容量（Vc）减少。一种同时测量一氧化氮（NO）和一氧化碳（CO）摄取的单次呼吸试验，可提供膜扩散（Dm）和Vc的简单实用测量方法。
对测量一氧化碳气体转移（TLCO）的标准单次呼吸试验进行调整，使其在吸入气体混合物中包含NO（40 ppm），并采用在肺总量时屏气7.5秒的方法。对12例原发性肺动脉高压患者和10名类似的正常志愿者在静息坐位时进行研究。
患者的TLCO和TLNO值降低。患者的Dm平均值（标准差）为36.7（32.1）mmol/min.kPa，而正常受试者为52.8（23.9）mmol/min.kPa。患者的Vc为0.03（0.03）L，正常受试者为0.06（0.01）L。
在健康志愿者和原发性高血压患者中可以同时测量NO和CO摄取。与正常受试者相比，这些患者的毛细血管血容量减少。
