Long-term oxygen therapy in chronic respiratory failure: A Multicenter Italian Study on Oxygen Therapy Adherence (MISOTA)

Development and preliminary psychometric evaluation of the COPD-related Stigma Scale

BACKGROUND

Stigma experiences contribute to psychological distress and negatively affect healthcare-seeking behavior in people with chronic obstructive pulmonary disease (COPD). Most evidence comes from qualitative research, and no well-established measure of COPD-related stigma exists. Prior research yielded a preliminary measure of COPD-related stigma, but it required item reduction and validation.

OBJECTIVES

The purpose of this study was to revise the preliminary measure, reduce the number of items, identify underlying constructs, and evaluate the reliability and validity of the shortened version.

METHODS

A descriptive, cross-sectional study was conducted. Participants (N = 148; mean = 64 ± 7.27 years) completed the 51-item preliminary COPD-related Stigma Scale (COPDSS). Item-level analysis was conducted before running exploratory factor analysis (EFA). Reliability was assessed using Cronbach's alpha. Convergent validity and known-groups validity were evaluated.

RESULTS

In the item-level analysis, eight items were deleted, leaving 43 items for factor analysis. A four-factor model with 24 items (α = 0.93) was derived from EFA: social stigma (α = 0.95), felt stigma (α = 0.95), anticipated stigma-oxygen (α = 0.80), and smoking-related stigma (α = 0.81). The 24-item COPDSS was significantly correlated with the 8-item Stigma Scale for Chronic Illness (r = 0.83), the Hospital Anxiety and Depression Scale (r = 0.57), and the PROMIS Physical Function (r = -0.48). The 24-item COPDSS discriminated between known groups based on age (p = .03), use of inhalers (p = .002) and use of supplemental oxygen (p < .001), and psychological distress levels (ps < .001).

CONCLUSION

Findings support the reliability and validity of the 24-item COPDSS. This instrument can be used to understand underlying stigma processes in people with COPD.

Long-term oxygen therapy prescription in India: Evaluation of compliance, factors affecting compliance, indications, and survival

Introduction:

The international data shows that long-term oxygen therapy (LTOT) compliance is insufficient and variable. We conducted the first study from India on LTOT compliance, factors affecting compliance, indications, and survival through oxygen concentrator.

Materials and Methods:

Our organization from Delhi had given 378 oxygen concentrators over the last 5 years. We evaluated 120 patients randomly for participating in the study. Compliance was defined as the use of LTOT for at least 15 h/day.

Results:

Ninety-seven patients were included in the final analysis after exclusion criteria. The compliance to LTOT was seen in 45.36% (44/97). The commonest cause of noncompliance was lack of instructions (49.06%) followed by electricity issues, social stigma, and workplace constraints. A higher PaCO₂ was associated with significantly lower compliance (PaCO₂ 53.18 vs. 44.98 mmHg, P = 0.036). Interstitial lung disease was associated with significantly higher compliance. Oxygen prescription was titrated with arterial blood gas analysis in only 4.12%. The indications for LTOT were chronic obstructive pulmonary disease (49.48%), posttuberculous obstructive airway disease (20.6%), and interstitial lung disease (12.37%). We found a significant reduction in the mean number of exacerbations/year from 3.91 to 1.93 (P < 0.0001). 61.86% of the patients were surviving on LTOT with a median survival time of 12 months.

Conclusion:

The adherence to LTOT in Indian patients is suboptimal mainly due to lack of instruction and is associated with a higher PaCO₂. The practice of titration needs to be followed. The development of a national registry to monitor LTOT should be the long-term target.

Lack of Medical Criteria for Long-Term Oxygen Therapy Usage According to International Guidance in Outpatients With Chronic Hypoxemia

Background

Benefits of long-term oxygen therapy (LTOT) have been observed in hypoxemic respiratory patients. Reports have shown the lack of observance among healthcare professionals of LTOT. Thus, this study aimed to determine the demographic characteristics and observance of the medical indication of LTOT according to the international guidelines.

Methodology

A cross-sectional study was conducted on patients who attended the Medical Unit in Aguascalientes, Mexico to re-evaluate the need for LTOT. Data are presented as mean ± standard deviation. Statistical analyses were performed using the chi-square test or unpaired t-tests. P-values of <0.05 were considered statistically significant.

Results

From 813 outpatients attended to re-evaluate whether they met the medical criteria to use LTOT, 93 outpatients were excluded, and the remaining 714 outpatients were enrolled. The mean age of the patients was 70.0 ± 15.1 years, with a female gender predominance (59.1 %). The mean PaO₂ level in room air was 7.9 ± 2.3 kPa. Hemoglobin and hematocrit levels were 14.9 ± 4.1 g/dL and 44.7 ± 8.4%, respectively. The mean levels of PaO₂ were higher in female patients (8.1 ± 2.5 kPa vs. 7.6 ± 1.9 kPa; p = 0.01). The most common diagnosis was chronic obstructive pulmonary disorder (60.5%). Moreover, the specialty that most indicated the use of LTOT was pulmonology (57.8%); however, 36.8% of patients who used LTOT did not have any criteria according to international guidelines.

Conclusions

Although a significant percentage of patients do not use LTOT correctly, the most important finding is that the medical indication of LTOT by physicians is not always correct, leading to an excessive prescription of oxygen.

[Oxygen Therapy in Lung Transplantation Candidates - A Single Center Retrospective Analysis of 807 Patients]

BACKGROUND

 Long-term oxygen treatment (LTOT) is frequently used in patients with advanced pulmonary diseases and respiratory failure. Oxygen treatment influences donor lung allocation for patients and is associated with increased mortality. This study investigates oxygen therapy in lung transplantation candidates.

METHODS

 A retrospective study at a large German transplantation centre between 09/2011 and 01/2019 was performed. Data regarding oxygen therapy was analyzed and LTOT-indication verified by titrated blood gas analysis. The study period splits into 2 periods before and after the introduction of oxygen titration (3rd quarter of 2015). Univariate and multivariate analysis for the endpoint "admission to waiting list" was performed.

RESULTS

 807 patients were included in the analysis, 396 in the first and 411 patients in the second period. Of those 293 patients (36.3 %) were transplanted. Six hundred thirty (78 %) patients stated using oxygen for more than 12 hours per day. After implementing oxygen titration in period 2, in 212 (57 %) of 372 patients LTOT indication could be confirmed. Titrated oxygen flow was lower in period 2 (0.5 l/min [IQR 0.0 - 2.0] versus 2 l/min [IQR 0.5 - 3.0]). In multivariate analysis oxygen flow was associated with admission to waiting list as an independent variable.

CONCLUSION

 Patients referred to lung transplantation use oxygen therapy in the vast majority. Indication for LTOT should be carefully reassessed in candidates. Confirmed LTOT-indication seems to be associated with the likelihood for admission to the waiting list for lung transplantation and could therefore be a selection criterium in the future.

Oxygen Indications and Utilization in a Diverse, Urban Community Setting

PURPOSE

Long-term oxygen therapy (LTOT) is widely used to treat chronic obstructive pulmonary disease (COPD) and other conditions with severe hypoxemia, imposing a large financial burden on the American health care system.

METHODS

To better understand oxygen prescription and its use in a multiethnic community hospital, we completed a prospective, observational study with a survey design in our multicultural population to better recognize patient understanding of oxygen indications and utilization.

RESULTS

The survey was conducted at three outpatient pulmonary clinics. Among the 94 respondents (42% men and 58% women; age 71.8 ± 13 yr), 64% were current or former smokers. Sixty-one percent had primary diagnoses other than COPD, most commonly interstitial lung disease and congestive heart failure. One-third used oxygen for <12 hr daily. Oxygen use was variable among those to whom it was prescribed. Thirty-two percent of patients described themselves as noncompliant with their prescribed therapy due to poor equipment ergonomics, burdensome machine weight, and negative self-image and social stigma when using oxygen.

CONCLUSIONS

Chronic obstructive pulmonary disease represented <50% of LTOT patients who were surveyed. Our data suggest that more structured prescribing practices and patient education should be studied if compliance is to be increased.

Oxygen devices and delivery systems

Oxygen use has extended from inpatient to outpatient settings for patients with chronic pulmonary diseases and complications of hypoxaemia. This article presents an overview of oxygen devices (oxygen concentrators, compressed gas cylinders and liquid oxygen) and delivery systems (high- and low-flow). The indications, advantages and disadvantages of each device and delivery system are presented, aiming to offer updated knowledge to the multidisciplinary team members managing patients with respiratory failure, and therefore allowing appropriate selection of devices and delivery systems that are tailored to the needs of each patient.

Oxygen therapy in COPD and interstitial lung disease: navigating the knowns and unknowns

Domiciliary oxygen therapy is often prescribed for patients with hypoxaemia due to advanced lung disease, most commonly chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). Long-term oxygen therapy (LTOT) trials conducted in patients with COPD in the 1980s remain the basis for clinical decisions and guideline recommendations regarding LTOT for patients with non-COPD conditions as there is a lack of high-quality evidence concerning its use in the non-COPD population. There is also a lack of evidence for the use of ambulatory and nocturnal oxygen therapy in patients with isolated exertional and nocturnal hypoxaemia. These deficiencies pose significant challenges in patient care, with consequent discrepancies in guideline recommendations and clinical approaches. In recent years, new studies have been and are currently being conducted to fill the gaps in our understanding and use of domiciliary oxygen therapy for other indications, including ILD. This article provides a comparison of the epidemiology and significance of hypoxaemia in patients with COPD and ILD, with an up-to-date review of current evidence regarding the role of different types of domiciliary oxygen therapy in these conditions.

Despite the significance of hypoxaemia in patients with chronic lung diseases, an up-to-date review shows current evidence for clinical use of domiciliary oxygen therapy remains limitedhttp://bit.ly/33aW31n

Home oxygen therapy: re-thinking the role of devices

INTRODUCTION

A range of devices are available for delivering and monitoring home oxygen therapy (HOT). Guidelines do not give indications for the choice of the delivery device but recommend the use of an ambulatory system in subjects on HOT whilst walking. Areas covered: We provide a clinical overview of HOT and review traditional and newer delivery and monitoring devices for HOT. Despite relevant technology advancements, clinicians, faced with many challenges when they prescribe oxygen therapy, often remain familiar to traditional devices and continuous flow delivery of oxygen. Some self-filling delivery-less devices could increase the users' level of independence with ecological advantage and, perhaps, reduced cost. Some newer portable oxygen concentrators are being available, but more work is needed to understand their performances in different diseases and clinical settings. Pulse oximetry has gained large diffusion worldwide and some models permit long-term monitoring. Some closed-loop portable monitoring devices are also able to adjust oxygen flow automatically in accordance with the different needs of everyday life. This might help to improve adherence and the practice of proper oxygen titration that has often been omitted because difficult to perform and time-consuming. Expert commentary: The prescribing physicians should know the characteristics of newer devices and use technological advancements to improve the practice of HOT.

A nationwide structure for valid long-term oxygen therapy: 29-year prospective data in Sweden

Background

Long-term oxygen therapy (LTOT) improves prognosis in COPD with severe hypoxemia. However, adherence to criteria for eligibility and quality of LTOT is often insufficient and varies between countries. The aim of this study was to evaluate a national structure for prescription and management of LTOT over three decades in Sweden.

Methods

The study was a prospective, population-based study of 23,909 patients on LTOT from 1987 to 2015 in the Swedish National Register of Respiratory Failure (Swedevox). We assessed the prevalence, incidence, and structure of LTOT; completeness of registration in Swedevox; and validity of prescription and management of LTOT in Sweden according to seven published quality indicators.

Results

LTOT was prescribed by 48 respiratory or medicine units and managed mainly by specialized oxygen nurses. Swedevox had a stable completeness of 85% of patients starting LTOT since 1987. The national incidence of LTOT increased from 3.9 to 14.7/100,000 inhabitants over the time period. In 2015, 2,596 patients had ongoing therapeutic LTOT in the registry, a national prevalence of 31.6/100,000. Adherence to prescription recommendations and fulfillment of quality criteria was stable or improved over time. Of patients starting LTOT in 2015, 88% had severe hypoxemia (partial pressure of arterial oxygen [PaO₂] <7.4 kPa) and 97% had any degree of hypoxemia (PaO₂ <8.0 kPa); 98% were prescribed oxygen ≥15 hours/day or more; 76% had both stationary and mobile oxygen equipment; 75% had a mean PaO₂ >8.0 kPa breathing oxygen; and 98% were non-smokers.

Conclusion

We present a structure for prescription, management, and follow-up of LTOT. The national registry effectively monitored adherence to prescription recommendations and most likely contributed to improved quality of care.

Why Don't Our Patients with Chronic Obstructive Pulmonary Disease Listen to Us? The Enigma of Nonadherence

Nonadherence--not taking pharmacologic or nonpharmacologic treatments according to agreed recommendations from a health care provider--is common in patients with chronic obstructive pulmonary disease. Nonadherence in taking maintenance medications, smoking cessation, maintaining regular physical activity and exercise, starting and staying in pulmonary rehabilitation and continuing on with the postrehabilitation exercise/activity prescription, and successfully following self-management directions results in adverse outcomes across multiple areas. These include a faster decline in airway function, higher symptom burden, impaired health status, and increased health care use and mortality risk. Although nonadherence can also occur in health care providers (not following established treatment guidelines), this perspective focuses on patient nonadherence. Factors such as social/economic, health system, therapy-related, patient-related, and condition-related factors all impact this problem. To improve patient adherence, we need to consider these factors in the context of people with chronic obstructive pulmonary disease and implement strategies directly targeting underlying issues. Strategies may include customizing and simplifying learning and intervention regimes, identifying barriers to adherence and addressing them, ensuring patient support structures are in place, and improving self-efficacy. Future directions should focus on research and development in educational design; use of technology to assist education; psychological intervention strategies to support learning, motivation, self-efficacy and behavior change; and ways to improve healthcare providers' engagement with patients.

Integrating COPD into Patient-Centered Hospital Readmissions Reduction Programs

About 1 in 5 patients hospitalized for exacerbations of chronic obstructive pulmonary disease (COPD) in the United States are readmitted within 30 days. The U.S. Centers for Medicare and Medicaid Services has recently expanded its Hospital Readmissions Reduction Program to financially penalize hospitals with higher than expected all-cause 30-day readmission rates following a hospitalization for COPD exacerbation. In October 2013, the COPD Foundation convened a multi-stakeholder National COPD Readmissions Summit to summarize our understanding of how to reduce hospital readmissions in patients hospitalized for COPD exacerbations. Over 225 individuals participated in the Summit, including patients, clinicians, health service researchers, policy makers and representatives of academic health care centers, industry, and payers. Summit participants recommend that programs to reduce hospital readmissions: 1) Include specific recommendations about how to promote COPD self-management skills training for patients and their caregivers; 2) Adequately address co-existing disorders common to COPD in care plans during and after hospitalizations; 3) Include an evaluation of adverse events when implementing strategies to reduce hospital readmissions; and 4) Develop a strategy (e.g., a learning collaboratory) to connect groups who are engaged in developing, testing, and implementing programs to reduce hospital readmissions for COPD and other conditions.

How do health-care professionals perceive oxygen therapy? A critical interpretive synthesis of the literature

Oxygen is one of the commonest health-care interventions worldwide. This might suggest that health-care professionals (HCPs) would be knowledgeable and familiar with its uses and limitations. Yet it is apparent, through clinical audit, that oxygen is probably misunderstood by many HCPs. The aim of this critical interpretive synthesis (CIS) is to explore qualitative and quantitative literature in relation to HCPs beliefs and perceptions of oxygen therapy. A systematic search in Medline, Cinahl, Embase, British Nursing Index and PsychInfo using search terms, such as, oxygen therapy, chronic respiratory disease, HCPs and perceptions yielded 1514 studies of which 12 contained data relevant to the review question. Two reviewers independently screened the articles for eligibility against inclusion and exclusion criteria, and data were selected and synthesized with an integrative and interpretive approach using CIS. This allowed diverse empirical evidence to be synthesized to develop existing and new interpretations of data.Three synthetic constructs were interpreted from the available literature, namely, oxygen for symptom relief, levels of knowledge and understanding and oxygen as a therapy for HCPs. The literature alludes to deep-seated beliefs that exist. In order to enhance practice, these beliefs and cultures need to be challenged. Further research is needed to explore HCPs’ perceptions of oxygen therapy in order to inform the seemingly resistant adoption of evidence based practice in relation to oxygen.

How do respiratory patients perceive oxygen therapy? A critical interpretative synthesis of the literature

Oxygen therapy is a common intervention in health care worldwide; yet, despite universal use, it is evident through poor practice that oxygen is often prescribed and administered injudiciously. It is proposed that possibly an influencing culture presides, whereby oxygen is often poorly understood and uncertainty regarding its use exists. It is unclear where the origins of this culture lie but exploring perceptions may enlighten the problem. A review of the literature was undertaken to establish what is already known about this elusive phenomenon. The paucity of any direct evidence regarding perceptions of oxygen directed the review to utilize a critical interpretative synthesis (CIS). The aim of this study was to explore how respiratory patients perceive oxygen therapy. A systematic search in Medline, Cinahl, Embase, British Nursing Index and PsychInfo yielded 1514 studies of which 42 were selected to consider the review question. The CIS allowed evidence from across studies to synthesize existing and new interpretations of data related to patients' perceptions of oxygen therapy. Synthetic constructs then informed the synthesizing arguments, namely positive - feeling safe, enabler and comforter; negative - fear, oxygen versus self, restriction and embarrassment; and impartiality - mixed blessings. The findings are divergent, and at times contradictory. There appears uncertainty among patients regarding the purpose and benefits of oxygen therapy, though an underlying faith in health-care professionals is apparent. This faith seems to foster acceptance of a life-changing therapy, despite the impact, burden and incomplete understanding. There is a clear need for further research regarding these elusive perceptions in order to improve clinical practice in respect of oxygen.

Pulmonary hypertension and right heart dysfunction in chronic lung disease

Group 3 pulmonary hypertension (PH) is a common complication of chronic lung disease (CLD), including chronic obstructive pulmonary disease (COPD), interstitial lung disease, and sleep-disordered breathing. Development of PH is associated with poor prognosis and may progress to right heart failure, however, in the majority of the patients with CLD, PH is mild to moderate and only a small number of patients develop severe PH. The pathophysiology of PH in CLD is multifactorial and includes hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, small vessel destruction, and fibrosis. The effects of PH on the right ventricle (RV) range between early RV remodeling, hypertrophy, dilatation, and eventual failure with associated increased mortality. The golden standard for diagnosis of PH is right heart catheterization, however, evidence of PH can be appreciated on clinical examination, serology, radiological imaging, and Doppler echocardiography. Treatment of PH in CLD focuses on management of the underlying lung disorder and hypoxia. There is, however, limited evidence to suggest that PH-specific vasodilators such as phosphodiesterase-type 5 inhibitors, endothelin receptor antagonists, and prostanoids may have a role in the treatment of patients with CLD and moderate-to-severe PH.

Poor adherence to guidelines for long-term oxygen therapy (LTOT) in two Italian university hospitals

Long-term oxygen therapy (LTOT) improves survival in patients with chronic obstructive pulmonary disease (COPD) and severe hypoxemia. Adherence to LTOT guidelines is problematic, both because efficacy has been demonstrated only in specific groups of COPD patients, and because it implies high costs. Introduces treatment high costs. The aim of our study was to examine retrospectively the adherence to LTOT guidelines in a sample of medical records of patients prescribed LTOT between January 2005 and December 2006 in two Italian university hospitals (Ferrara and Modena). Out of a total of 191 medical records of patients prescribed LTOT, only 157 had adequate clinical data considering the three main criteria for appropriateness (arterial blood gas and/or pulse oximetry measurement, oxygen administration, smoking status). Out of these 157 patients, only 73 (46.5 %) fulfilled all three criteria recommended by the guidelines. Adherence was higher for LTOT prescribed by pulmonologists compared to internists. This survey showed that the adherence to LTOT guidelines in a sample of medical records of patients prescribed LTOT is poor. Considering the high costs and the impact on the patients' quality of life of LTOT, these results suggest that the adherence should be carefully monitored.

Long-term oxygen therapy

Long-term oxygen therapy (LTOT) has been shown to reduce pulmonary hypertension and improve survival in patients with chronic obstructive pulmonary disease and resting hypoxemia (reduced arterial partial pressure of oxygen ≤55 mmHg). However, the benefit of its use for chronic pulmonary diseases other than chronic obstructive pulmonary disease as well as for nonpulmonary conditions is debatable. Its role in patients with mild hypoxemia (reduced arterial partial pressure of oxygen >55 mmHg at rest) is presently being investigated in the LOTT. A meta-analysis of four controlled trials reporting the role of LTOT in patients with either nocturnal desaturation or daytime moderate hypoxemia found no difference in survival between patients on LTOT than those without. Advances in oxygen delivery and conservation devices have made domiciliary oxygen therapy more practical and popular for patients. There still remain concerns with the actual compliance of therapy among the needy patients.

The importance of knowing the home conditions of patients receiving long-term oxygen therapy

Purpose

Long-term oxygen therapy (LTOT) is one of the main treatments for patients with chronic obstructive pulmonary disease. Patients receiving LTOT may have less than optimal home conditions and this may interfere with treatment. The objective of this study was, through home visits, to identify the characteristics of patients receiving LTOT and to develop knowledge regarding the home environments of these patients.

Methods

Ninety-seven patients with a mean age of 69 plus or minus 10.5 years were evaluated. This study was a cross-sectional descriptive analysis. Data were collected during an initial home visit, using a questionnaire standardized for the study. The results were analyzed retrospectively.

Results

Seventy-five percent of the patients had chronic obstructive pulmonary disease, and 11% were active smokers. The patients’ mean pulse oximetry values were 85.9% plus or minus 4.7% on room air and 92% plus or minus 3.9% on the prescribed flow of oxygen. Most of the patients did not use the treatment as prescribed and most used a humidifier. The extension hose had a mean length of 5 plus or minus 3.9 m (range, 1.5–16 m). In the year prior to the visit, 26% of the patients received emergency medical care because of respiratory problems. Few patients reported engaging in leisure activities.

Conclusion

The home visit allowed us to identify problems and interventions that could improve the way LTOT is used. The most common interventions related to smoking cessation, concentrator maintenance and cleaning, use of a humidifier, and adjustments of the length of the connector hose. Therefore, the home visit is a very important tool in providing comprehensive care to patients receiving LTOT, especially those who show lack of adequate progress and those who show uncertainty about the treatment method.

Long-Term Oxygen Therapy in COPD: Factors Affecting and Ways of Improving Patient Compliance

Long-term oxygen therapy (LTOT) is the cornerstone mode of treatment in patients with severe chronic obstructive pulmonary disease (COPD) associated with resting hypoxaemia. When appropriately prescribed and correctly used, LTOT has clearly been shown to improve survival in hypoxemic COPD patients. Adherence to LTOT ranges from 45% to 70% and utilization for more than 15 hours per day is widely accepted as efficacious. Although several studies have addressed the level of patients' adherence to LTOT, few have suggested or evaluated interventions that conduce to compliance enhancement. The lack of sufficient data regarding COPD patients following oxygen prescription is an enormous void that must be duly confronted to augment clinical effectiveness and cost containment for the long term use. The present review article highlights factors influencing the compliance of patients using LTOT and emphasizes novel strategies and interventions that may prove to be of significant benefit given the remarkably little current research appraising this issue. Therefore, additional research should be promptly performed to verify the efficacy of newly designed approaches in improving the outcomes of patients receiving LTOT.

What really matters to patients living with chronic obstructive pulmonary disease? An exploratory study

There is limited published research into what really matters to people living with chronic obstructive pulmonary disease (COPD). Most previous research in this area focuses on the impact of the symptoms of COPD, rather than on the issues defined as important by patients themselves. This paper describes an exploratory study investigating what is most important to people living with COPD. A qualitative approach employing in-depth interviews with COPD patients was chosen. Thematic analysis was used to code and categorize data. Six patients with 'moderate' to 'very severe' COPD were recruited. They considered engagement in specific activities to be very important (walking, household maintenance and driving), even though these activities were mainly centred around the home environment, or within confined spaces, due to their physical limitations. This restriction led to feelings of social isolation that these patients tried to overcome through social participation (holidays, social interaction). People with COPD often experience physical restrictions, which can lead to reduced community mobility and social isolation. In this study, despite their physical limitations, these patients had a strong desire to participate and be engaged in various activities. The importance of enabling patients to 'participate' rather than just 'do' should be considered when planning and delivering patient-centred interventions across the whole spectrum of severity of COPD.

Long-term oxygen treatment in chronic obstructive pulmonary disease: recommendations for future research: an NHLBI workshop report

Long-term oxygen treatment (LTOT) prolongs life in patients with chronic obstructive pulmonary disease (COPD) and severe resting hypoxemia. Although this benefit is proven by clinical trials, scientific research has not provided definitive guidance regarding who should receive LTOT and how it should be delivered. Deficiencies in knowledge and in current research activity related to LTOT are especially striking in comparison to the importance of LTOT in the management of COPD and the associated costs. The National Heart, Lung, and Blood Institute, in collaboration with the Centers for Medicare and Medicaid Services, convened a working group to discuss research on LTOT. Participants in this meeting identified specific areas in which further investigation would likely lead to improvements in the care of patients with COPD or reductions in the cost of their care. The group recommended four clinical trials in subjects with COPD: (1) efficacy of ambulatory O(2) supplementation in subjects who experience oxyhemoglobin desaturation during physical activity but are not severely hypoxemic at rest; (2) efficacy of LTOT in subjects with severe COPD and only moderate hypoxemia; (3) efficacy of nocturnal O(2) supplementation in subjects who show episodic desaturation during sleep that is not attributable to obstructive sleep apnea; and (4) effectiveness of an activity-dependent prescription for O(2) flow rate that is based on clinical tests performed at rest, during exercise, and during sleep.