Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine of MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109, USA.
Am J Respir Crit Care Med. 2010 May 15;181(10):1061-71. doi: 10.1164/rccm.200910-1638OC. Epub 2010 Feb 4.
Clinical testing of oxygen-conserving devices is not mandated before marketing. Consequently, little is known about individual or comparative therapeutic effectiveness.
To relate oxygen delivery from prototypical instruments to physiological performance.
Thirteen subjects with obstructive lung disease performed progressive treadmill exercise while inhaling either room air, 2 L O(2)/min, or bolus oxygen from four commercially available conserving devices at regulator settings of 2, 5, and continuous. The devices were studied blindly in random order after first being tested to determine performance characteristics. Pulse oximetry, oxygen delivery, and nasal and oral ventilations were monitored at rest and with exertion.
At a setting of 2 at rest, all conservers maintained saturation greater than 90%, but there were significant differences in oxygenation between systems. Only one equaled 2 L O(2)/min. With exertion, saturation decreased with all conservers but not with 2 L O(2)/min. One device did not perform any better than room air. Two systems provided less oxygen than predicted, one more, and in one the expected and actual amounts were equal only at rest. Breath-by-breath performance was highly variable, with irregular activation and inconsistent oxygen bolus size delivery. Increasing oxygen pulse volume to the point of eradicating conservation with the continuous setting did not eliminate all disparities.
The mechanical and clinical performances of current oxygen conservers are highly variable and in some instances actually contribute to limitations in exercise ability. Seemingly equivalent technical features do not guarantee equivalent therapeutic functionality.
在上市前，并未强制要求对氧气节约装置进行临床测试。因此，对于其个体或比较治疗效果，我们知之甚少。
将原型仪器的氧气输送与生理性能相关联。
13 名患有阻塞性肺疾病的受试者在跑步机上进行渐进式运动，同时分别吸入环境空气、2 L/min 的氧气或来自四种市售的节约装置的脉冲式氧气，这些装置在 2、5 和连续调节下进行测试，以确定其性能特征，然后以随机顺序进行盲法研究。在休息和运动时监测脉搏血氧饱和度、氧气输送以及鼻和口通气。
在休息时，所有的节约器在设置为 2 时都能维持饱和度大于 90%，但系统之间的氧合存在显著差异。只有一个能达到 2 L/min 的氧气输送量。在运动时，所有的节约器都会导致饱和度下降，但 2 L/min 的氧气输送不会。有一个装置的性能并不比环境空气好。有两个系统提供的氧气量少于预期，一个系统提供的氧气量多于预期，而在一个系统中，仅在休息时，预期和实际的氧气输送量才相等。呼吸的性能高度可变，激活不规则且氧气脉冲量输送不一致。将氧气脉冲量增加到消除连续设置下的节约效果的程度，并不能消除所有差异。
当前氧气节约器的机械和临床性能差异很大，在某些情况下实际上会导致运动能力受限。看似相同的技术特点并不能保证相同的治疗功能。
