BENEFITS OF AMBULATORY OXYGEN IN HYPOXEMIC COPD PATIENTS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 慢性阻塞性肺疾病(COPD)患者经历慢性低氧水平，预后特别差。20多年前，研究表明，长期向这些患者提供补充氧气可以带来显著的好处，包括提高存活率。今天，长期氧疗(LTOT)被认为是低氧血症COPD患者的标准护理，在美国约有75万名患者。然而，相当大的争议依然存在。一些权威人士认为，非卧床氧疗对患者是有益的，事实上，患者容易携带的氧疗装置(重量不到5磅)在市场上是可以买到的。然而，绝大多数能够走动的低氧血症患者只接受E钢瓶中的加压氧气供应，重约22磅，由患者用轮式手推车拖着。专家意见和临床实践之间的差异之所以存在，是因为我们不知道配备了轻型门诊系统的患者是否更好地遵守了氧气处方，并增加了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，比较使用轻型动态氧气系统和便携式E钢瓶系统的生理和临床益处。 这将是一项多中心、非盲目、对照试验，随机选择7个临床中心的100名受试者。符合条件的受试者将被分配到对照治疗(E钢瓶)或治疗(轻量氧气供应)，1：1分配，使用按临床中心分层的随机区组。受试者将在两周的基准期内接受评估，然后在随机化后进行6个月的跟踪调查。将有基线、三个月和六个月的主要评价期。主要的结果衡量标准将是每天使用的氧气总小时数，次要结果衡量标准将是活动水平。 患者将在家中通过两台类似电脑的设备进行监控。其中一个将记录患者固定式氧气浓缩器每分钟的氧气使用情况。另一个将记录可移动源(轻型设备或E钢瓶)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。研究协调员将每月访问患者的家中，收集这些监护仪。患者还将在研究期间三次在腰带上佩戴寻呼机大小的设备2-3周；这种设备(三轴加速计)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，为期三天；绑在其中一个手指上的传感器将测量血液中的氧气水平。 患者将参观研究实验室5次。程序将包括： “病史和体检 “肺功能测试：患者呼吸急促并短暂屏气。 动脉和静脉采血以评估血液氧合和各种血液化学和血液学测试 “运动测试(包括递增和恒定工作速率测试)评估心肺风险和确定运动耐量 “在休息和运动时进行氧气滴定，以确定合适的氧气处方。这将包括确定在休息和运动过程中维持动脉血液中充足氧气水平所需的氧气流量。为此，脉搏血氧仪将(无创)测量氧气水平，因为氧气流量在患者休息和跑步机运动测试期间进行调整。” “6分钟步行试验评估功能性运动耐量 “用于确定生活质量、呼吸困难严重程度、抑郁、精神状态、协调性和成本效益的问卷调查 “将举行一次教育会议，强调氧疗的价值和增加活动的好处。 只有目前供氧量超过10磅并用手推车携带以供行走的患者才会被招募，这样就不会要求患者放弃轻量级的非卧床供氧。参与的受试者将受益于获得一套医疗评估。如果明确定义轻量非卧床供氧的益处，COPD患者作为一个群体的益处可能是相当大的。风险不大；具体地说，监控设备没有已知的风险。因此，总体风险/收益比率是有利的。

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.