BENEFITS OF AMBULATORY OXYGEN IN HYPOXEMIC COPD PATIENTS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 经历慢性低氧水平的慢性阻塞性肺疾病（COPD）患者具有特别差的预后。 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巨大的好处，包括提高生存率。 今天，长期氧疗（LTOT）被认为是低氧血症COPD患者的标准治疗，在美国约有75万患者接受了这种治疗，但仍存在相当大的争议。 一些权威人士认为，便携式氧疗对患者有益，事实上，患者容易携带的装置（重量小于5磅）是市售的。 然而，绝大多数能够走动的低氧血症患者仅被供应E-气瓶中的加压氧气，重量约为22磅，由患者在轮式推车上拖曳。 专家意见和临床实践之间存在这种差异，因为我们不知道是否为患者提供了轻便的流动系统，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例低氧性COPD患者中进行一项多中心（7家临床试验机构）随机试验，比较使用轻型便携式氧气系统与便携式E型气瓶系统的生理和临床受益。 这将是一项多中心、非盲、对照试验，在7个临床中心随机分配100例受试者。 合格受试者将按照1：1的比例分配接受对照治疗（E-cylinder）或治疗治疗（轻质供氧），并使用按临床中心分层的随机区组。 将在两周基线期内对受试者进行评价，然后在随机化后随访6个月。 将在基线、三个月和六个月时进行主要评价。 主要结果测量将是每日使用氧气的总小时数，次要结果测量将是活动水平。 患者将在家中通过两台类似计算机的设备进行监测。 其中一个将记录病人的固定氧气浓缩器每分钟的氧气使用情况。 另一个将记录移动源（轻型设备或E型气瓶）的每分钟氧气使用情况。 这些设备一次可以收集一个多月的数据。 研究协调员将每月访视患者家中以收集这些监测器。 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，共三次;该设备（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3天;一个贴在手指上的传感器将测量血液中的氧气水平。 患者将5次访视研究实验室。 程序将包括; " 病史和体格检查 " 肺功能测试，患者将用力呼吸并短暂屏住呼吸 " 动脉和静脉采血，用于评估血氧合和各种血液化学和血液学检查 " 运动测试（增量和恒定功率测试），以评估心肺风险并确定运动耐量 " 休息和运动时的氧气滴定，以确定适当的氧气处方。 这将涉及确定在休息和运动期间维持动脉血中足够的氧气水平所需的氧气流速。 为此，脉搏血氧仪将（无创）测量氧气水平，因为氧气流速是在患者休息和跑步机运动测试期间调整的。 " 6分钟步行试验评估功能性运动耐量 " 问卷调查，以确定生活质量、呼吸困难严重程度、抑郁、精神状态和协调性以及成本效用 " 将举行一次教育会议，强调氧疗的价值和增加活动的好处 只有目前氧气供应重量超过10磅，并在一个手推车进行救护的病人将被招募，所以没有病人将被要求放弃一个轻量级的流动氧气供应。 参与受试者将通过获得一组医学评价而受益。 如果明确定义轻型便携式氧气供应的益处，则COPD患者作为一个群体的益处可能相当大。 风险是适度的;具体而言，监测器械没有已知风险。 因此，总体风险/受益比有利。

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.