BENEFITS OF AMBULATORY OXYGEN IN HYPOXEMIC COPD PATIENTS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。慢性阻塞性肺疾病（COPD）患者经历慢性低氧水平有特别差的预后。20多年前，研究表明，长期为这些患者提供补充氧气可以带来显着的益处，包括提高生存率。如今，长期氧疗（LTOT）被认为是低氧性COPD患者的标准治疗方法，在美国约有75万名患者采用这种治疗方法。然而，相当大的争议仍然存在。一些权威人士认为，动态氧疗对患者有益，事实上，市场上可以买到便于患者携带的设备（重量小于5磅）。然而，绝大多数能够走动的低氧血症患者只能使用重约22磅的e型气瓶增压氧气，由患者用轮式手推车牵引。专家意见和临床实践之间存在这种差异，因为我们不知道提供轻型门诊系统的患者是否更好地遵守氧气处方并增加他们的日常活动水平。我们建议在100名低氧血症COPD患者中进行一项多中心（7个地点）随机试验，比较使用轻型动态供氧系统与便携式电子气瓶系统的生理和临床益处。这将是一项多中心、非盲、对照试验，在7个临床中心随机选取100名受试者。符合条件的受试者将按临床中心分层随机分组，按1:1分配对照组（电子气瓶）或治疗组（轻量供氧）。受试者将在两周的基线期进行评估，然后在随机化后随访6个月。在基线、三个月和六个月将有主要的评价期。主要指标是每日总耗氧小时数，次要指标是活动量。患者将在家中接受两台类似电脑的设备的监控。其中一个将记录病人固定的氧气浓缩器每分钟的氧气使用情况。另一个将记录动态源（轻型设备或e-气缸）的每分钟氧气使用情况。这些设备一次可以收集一个月以上的数据。研究协调员将每月到患者家中收集这些监测器。在研究期间，患者还将在腰带上佩戴寻呼机大小的设备，为期2-3周，分三次佩戴；这个装置（一个三轴加速度计）将收集每分钟的活动水平。患者还将在手腕上佩戴一个设备，为期3天；绑在他们手指上的传感器将测量血液中的氧含量。患者将访问研究实验室5次。程序包括：“病史和体格检查”肺功能检查（患者用力呼吸并短暂屏住呼吸）“动脉和静脉血取样以评估血液氧合和各种血液化学和血液学检查”运动试验（增量和恒定工作速率试验）以评估心肺风险并确定运动耐量”休息和运动时的氧滴定以确定合适的氧处方。这将包括确定在休息和运动时维持动脉血中足够的氧气水平所需的氧流量。为了做到这一点，脉搏血氧仪将（无创）测量氧气水平，同时在病人休息和在跑步机运动测试中调整氧流量。“ 6分钟步行测试，评估功能性运动耐受性”问卷调查，确定生活质量，呼吸困难严重程度，抑郁，精神状态，协调和成本效用"将进行一个教育会议，强调氧气治疗的价值和增加活动的好处只招募目前氧气供应超过10磅并在手推车上行走的患者，这样病人就不会被要求放弃轻便的动态供氧。参与的受试者将受益于获得一套医疗评估。如果轻量动态供氧的益处得到明确定义，对COPD患者整体的益处可能是相当大的。风险是适度的；具体来说，监控设备没有已知的风险。因此，整体风险/收益比是有利的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Chronic obstructive pulmonary disease (COPD) patients who experience chronic low oxygen levels have an especially poor prognosis. More than 20 years ago, research studies demonstrated that chronic provision of supplemental oxygen to these patients provides dramatic benefits, including improved survival. Today, long-term oxygen therapy (LTOT) is considered to be the standard of care to hypoxemic COPD patients and about 750,000 patients in the United States it. Yet considerable controversy persists. Some authorities believe that ambulatory oxygen therapy is of benefit to the patient and, indeed, units easily carried by patients (weighing less than 5 lb) are commercially available. Yet the substantial majority of hypoxemic patients able to be ambulatory are supplied only with pressurized oxygen in E-cylinders, weighing about 22 lb and towed by the patient on a wheeled cart. This discrepancy between expert opinion and clinical practice exists because we do not know if patients provided with lightweight ambulatory systems have better compliance with oxygen prescription and increase their daily level of activity. We propose to perform a multicenter (7 sites) randomized trial in 100 hypoxemic COPD patients comparing the physiologic and clinical benefits of utilizing lightweight ambulatory oxygen systems versus portable E-cylinder systems. This will be a multi-center, unblinded, controlled trial randomizing 100 subjects across 7 clinical centers. Eligible subjects will be assigned control therapy (E-cylinder) or treatment therapy (light weight oxygen supply), in 1:1 allocation, using randomized blocks stratified by clinical center. Subjects will be evaluated during a two-week baseline period and then will be followed for 6 months post-randomization. There will be major evaluation periods at baseline, at three months and at six months. The primary outcome measure will be total daily hours of oxygen used and a secondary outcome measure will be level of activity. Patients will be monitored in their home by two computer-like devices. One will record minute-by-minute oxygen use of the patient's stationary oxygen concentrator. The other will record minute-by-minute oxygen use of the ambulatory source (lightweight device or E-cylinder). These devices can collect more than one month's data at a time. Study coordinators will visit the patient's home monthly to collect these monitors. Patients will also wear a pager-sized device on their belt for 2-3 week periods on three occasions during the study; this device (a tri-axial accelerometer) will collect minute-by-minute level of activity. Patients will also wear a device on their wrist for 3 two-day periods; a sensor taped to one of their fingers will measure the oxygen level in the blood. Patients will visit the study laboratory on 5 occasions. Procedures will include; " history and physical examination " pulmonary function testing in which patients will breathe forcefully and hold their breath for brief periods " arterial and venous blood sampling for assessment of blood oxygenation and various blood chemistry and hematology tests " exercise testing (both incremental & constant work rate testing) to assess cardiopulmonary risks and determine exercise tolerance " oxygen titration at rest and exercise to determine an appropriate oxygen prescription. This will involve determining the oxygen flow rate required to maintain an adequate level of oxygen in the arterial blood both at rest and during exercise. To do this, a pulse oximeter will (noninvasively) measure oxygen level as the oxygen flow rate is adjusted both with the patient at rest and during a treadmill exercise test. " 6 minute walk test to assess functional exercise tolerance " questionnaires to determine quality of life, dyspnea severity, depression, mental status and coordination and cost-utility " an education session will be conducted stressing the value of oxygen therapy and the benefits of increased activity Only patients currently oxygen supplies weighing over 10 pounds and carried in a cart for ambulation will be recruited, so that no patient will be asked to forego a lightweight ambulatory oxygen supply. Participating subjects will benefit by having access to a set of medical evaluations. The benefits to COPD patients as a group may be considerable if benefits of lightweight ambulatory oxygen supplies are clearly defined. The risks are modest; specifically, the monitoring devices have no known risks. The overall risk/benefit ratio is therefore favorable.