Characteristics and survival of patients prescribed long-term oxygen therapy outside prescription guidelines

Factors Associated With Change in S3-NIV Score Over Time in People With Chronic Respiratory Failure Treated With Long-Term Home Noninvasive Ventilation

INTRODUCTION

Monitoring changes in symptoms over time during long-term nocturnal home non-invasive ventilation (NIV) using patient-reported outcome measures is crucial. This study aimed to identify factors associated with changes in the S3-NIV total score, its two domains ("respiratory symptoms" and "sleep and NIV-related side effects") and individual item responses.

METHODS

We conducted a retrospective, longitudinal data analysis of a cohort of adults with chronic respiratory failure treated with NIV. Data were obtained from a French homecare provider. Multivariate linear and multinomial ordinal mixed effect models were used to identify factors associated with changes in S3-NIV scores over time.

RESULTS

Median follow-up was 2 years for 2135 participants. Each participant completed a median of five S3-NIV questionnaires; totaling 11,359 analyzed questionnaires. Type of respiratory condition, sex, age and time since NIV initiation were associated with change in S3-NIV score over time. NIV adherence was not associated with total S3-NIV score but high adherence was associated with more severe respiratory symptoms and an improvement in sleep and NIV-related side effects during the follow-up. Intensity of pressure support was associated with a lower total S3-NIV score and more side effects. Face masks and supplemental oxygen were associated with a lower S3-NIV total score.

CONCLUSION

Changes in S3-NIV scores over time are associated with the individual's characteristics and NIV settings. Analysis of the two domains and individual items of the S3-NIV could increase understanding of the difficulties experienced by people on NIV.

Incidence, management, and outcome of lung cancer in patients with long-term oxygen therapy

BACKGROUND

Here, we aimed to assess the specific features of lung cancer in patients with long-term oxygen therapy (LTOT), and compare their outcomes with patients suffering from lung cancer without LTOT.

METHODS

This retrospective, case-controlled study included patients with LTOT and an incident diagnosis of lung cancer treated at Rouen University Hospital.

RESULTS

Out of 2201 patients with LTOT, 31 were diagnosed with lung cancer. Among 24 patients with proven lung cancer, the most frequent histological type was squamous cell carcinoma (n = 12/24, 50%). Active treatment of any type was given in 19/31 (61%) and 41/62 (66%) of patients in the LTOT and control groups, respectively (p = 0.83). In the LTOT group, median survival was 38 days with best supportive care and 462 days with active treatment (p = 0.003). However, when adjusting on performance status and disease stage, LTOT was not significantly associated with a worse outcome. Hazard ratio (HR): 1.56 (95% confidence interval [CI]: 0.87 to 2.81) (p = 0.137). Administration of any treatment was associated with a better prognostic: HR: 0.35 (95% CI: 0.19 to 0.66). Both groups had a similar treatment safety profile.

CONCLUSION

Incidence of lung cancer in patients with LTOT was comparable to the general population. The proportion of LTOT patients who received active treatment was similar to controls, and overall survival did not differ from controls in a multivariate analysis. Although reaching a histological diagnosis may be challenging in LTOT patients, the efficacy and safety of the management strategies of lung cancer seem preserved.

Association between long-term oxygen therapy provided outside the guidelines and mortality in patients with COPD

INTRODUCTION

Hypoxaemia is a frequent complication of chronic obstructive pulmonary disease (COPD). To prevent its consequences, supplemental oxygen therapy is recommended by international respiratory societies. However, despite clear recommendations, some patients receive long-term oxygen therapy (LTOT), while they do not meet prescription criteria. While evidence suggests that acute oxygen supply at high oxygenation targets increases COPD mortality, its chronic effects on COPD mortality remain unclear. Thus, the study will aim to evaluate through a systematic review and individual patient data meta-analysis (IPD-MA), the association of LTOT prescription outside the guidelines on survival over time in COPD.

METHODS

Systematic review and IPD-MA will be conducted according to Preferred Reporting Items for a Systematic Review and Meta-Analyses IPD guidelines. Electronic databases (PubMed, Web of Science, EMBASE, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, OpenGrey and BioRxiv/MedRxix) will be scanned to identify relevant studies (cohort of stable COPD with arterial oxygen tension data available, with indication of LTOT filled out at the moment of the study and with a survival follow-up). The anticipated search dates are January-February 2022. The main outcome will be the association between LTOT and time to all-cause mortality according to hypoxaemia severity, after controlling for potential covariates and all available clinical characteristics. Quantitative data at the level of the individual patient will be used in a one-step approach to develop and validate a prognostic model with a Cox regression analysis. The one-step IPD-MA will be conducted to study the association and the moderators of association between supplemental oxygen therapy and mortality. Multilevel survival analyses using Cox-mixed effects models will be performed.

ETHICS AND DISSEMINATION

As a protocol for a systematic review, a formal ethics committee review is not required. Only studies with institutional approval from an ethics committee and anonymised IPD will be included. Results will be disseminated through peer-reviewed publications and presentations in conferences.

PROSPERO REGISTRATION NUMBER

CRD42020209823.

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.

Acute oxygen therapy: a cross-sectional study of prescribing practices at an English hospital immediately before COVID-19 pandemic

BACKGROUND

Approximately 14% of UK hospital in-patients receive supplemental oxygen therapy, only 57% have valid prescriptions. Oxygen must be optimally prescribed to ensure maximal therapeutic response whilst minimizing adverse outcomes (including fatality). This study investigates prescription compliance.

METHODS

All adults admitted to medical wards (18 February to 3 March 2020) were included. Analyses present proportions, descriptive statistics, and hypothesis testing. Ethical approval was unnecessary for this audit.

RESULTS

Of the 636 patients admitted, 66 (10%) were receiving oxygen therapy. Ages ranged from 34 to 100 years with 36 (54.5%) males and 30 (45.5%) females. The prescription was not documented in the oxygen section of the drug chart (n = 37, 56.1%, p = 0.389), nor did it have the physicians signature (n = 40, 60.6%, p = 0.110) nor date (n = 46, 69.7%, p = 0.002). Thirteen chronic obstructive pulmonary disease (COPD) patients (19.7%) were at risk of hypercapnic failure (p = 1.582x10^-6). Target oxygen saturation (SpO2) range had been documented for 30 (45.5%) patients. A target SpO2 range of 88-92% was documented for 9 patients (13.6%), a 94-98% range documented for 11 patients (16.7%). All patients had an invalid prescription.

CONCLUSION

We present real-world practice in naturalistic settings, immediately before pandemic-lockdown. Enhanced compliance is advocated to reduce risks of harm and mortality.

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

Transplant options for end stage chronic obstructive pulmonary disease in the context of multidisciplinary treatments

Lung transplantation (LTx) in advanced stage chronic obstructive pulmonary disease (COPD) patients is associated with significant improvement in lung function and exercise capacity. However, demonstration that the procedure also provides a survival benefit has been more elusive compared to other respiratory conditions. Identification of patients with increased risk of mortality is crucial: a low forced expiratory volume in 1 second (FEV₁) is perhaps the most common reason for referral to a lung transplant center, but in itself is insufficient to identify which COPD patients will benefit from LTx. Many variables have to be considered in the selection of candidates, time for listing, and choice of procedure: age, patient comorbidities, secondary pulmonary hypertension, the balance between individual and community benefit. This review will discuss patient selection, transplant listing, potential benefits and critical issues of bilateral (BLTx) and single lung (SLTx) procedure, donor-to-recipient organ size-matching; furthermore, it will describe LTx outcomes and its effects on recipient survival and quality of life.

Long-Term Oxygen Therapy in COPD Patients Who Do Not Meet the Actual Recommendations

Chronic respiratory failure due to chronic obstructive pulmonary disease (COPD) is an increasing problem worldwide. Many patients with severe COPD develop hypoxemic respiratory failure during the natural progression of disease. Long-term oxygen therapy (LTOT) is a well-established supportive treatment for COPD and has been shown to improve survival in patients who develop chronic hypoxemic respiratory failure. The degree of hypoxemia is severe when partial pressure of oxygen in arterial blood (PaO₂) is ≤55 mmHg and moderate if PaO₂ is between 56 and 69 mmHg. Although current guidelines consider LTOT only in patients with severe resting hypoxemia, many COPD patients with moderate to severe disease experience moderate hypoxemia at rest or during special circumstances, such as while sleeping or exercising. The efficacy of LTOT in these patients who do not meet the actual recommendations is still a matter of debate, and extensive research is still ongoing to understand the possible benefits of LTOT for survival and/or functional outcomes such as the sensation of dyspnea, exacerbation frequency, hospitalizations, exercise capacity, and quality of life. Despite its frequent use, the administration of "palliative" oxygen does not seem to improve dyspnea except for delivery with high-flow humidified oxygen. This narrative review will focus on current evidence for the effects of LTOT in the presence of moderate hypoxemia at rest, during sleep, or during exercise in COPD.

Oxygen desaturation in 6-min walk test is a risk factor for adverse outcomes in COPD

The 6-min walk test (6MWT) is an exercise test that measures functional status in chronic obstructive pulmonary disease (COPD) patients and provides information on oxygen desaturation. We investigated oxygen desaturation during 6MWT as a risk factor for important COPD outcomes: mortality, frequency of exacerbations, decline in lung function and decline in lean body mass.433 COPD patients were included in the Bergen COPD Cohort Study 2006-2009, and followed-up for 3 years. Patients were characterised using spirometry, bioelectrical impedance measurements, Charlson comorbidity score, exacerbation history, smoking and arterial blood gases. 370 patients completed the 6MWT at the baseline of the study. Information on all-cause mortality was collected in 2011.Patients who experienced oxygen desaturation during the 6MWT had an approximately twofold increased risk of death (hazard ratio 2.4, 95% CI 1.2-5.1), a 50% increased risk for experiencing later COPD exacerbations (incidence rate ratio 1.6, 95% CI 1.1-2.2), double the yearly rate of decline in both forced vital capacity and forced expiratory volume in 1 s (3.2% and 1.7% versus 1.7% and 0.9%, respectively) and manifold increased yearly rate of loss of lean body mass (0.18 kg·m(-2) versus 0.03 kg·m(-2) among those who did not desaturate).Desaturating COPD patients had a significantly worse prognosis than non-desaturating COPD patients, for multiple important disease outcomes.

Lung transplantation in chronic obstructive pulmonary disease: patient selection and special considerations

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity. Lung transplantation is one of the few treatments available for end-stage COPD with the potential to improve survival and quality of life. The selection of candidates and timing of listing present challenges, as COPD tends to progress fairly slowly, and survival after lung transplantation remains limited. Though the natural course of COPD is difficult to predict, the use of assessments of functional status and multivariable indices such as the BODE index can help identify which patients with COPD are at increased risk for mortality, and hence which are more likely to benefit from lung transplantation. Patients with COPD can undergo either single or bilateral lung transplantation. Although many studies suggest better long-term survival with bilateral lung transplant, especially in younger patients, this continues to be debated, and definitive recommendations about this cannot be made. Patients may be more susceptible to particular complications of transplant for COPD, including native lung hyperinflation, and development of lung cancer.

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.

Exertional desaturation in patients with chronic obstructive pulmonary disease

Although the Centers for Medicare and Medicaid Services oxygen prescription guidelines utilize a threshold arterial oxygen tension <or=55 mmHg or an oxygen saturation <or=88%, a range of oxygen levels and relative declines have been used in investigations of exertional desaturation in patients with chronic obstructive pulmonary disease (COPD). There is no uniform definition of exertional hypoxemia or standardized exercise protocol to elicit decreases in oxygen levels in individuals with COPD. The causes for exertional desaturation in patients with COPD are multifactorial with ventilation-perfusion mismatching, diffusion-type limitation, shunting and reduced oxygen content of mixed venous blood all contributing to some degree. Neither resting oxygen saturation nor pulmonary function studies can reliably predict which patients with COPD will develop exertional desaturation. However, preserved pulmonary function, especially diffusing capacity, reliably predicts which patients with COPD will sustain oxygenation during exercise. Although exertional desaturation in patients with COPD appears to portend a poor prognosis, there is no evidence that maintenance of normoxemia during exercise improves the survival of these patients. Studies of the effect of supplemental oxygen on exercise performance in individuals with COPD who desaturate with exertion have yielded conflicting results. The use of short-term or "burst" oxygen either prior to or after exertion may not have significant clinical benefit. Differences in the definition of desaturation, mode of exercise, and characteristics of the patient population make it difficult to compare studies of exertional desaturation and its treatment and to determine their applicability to clinical practice.

La vie quotidienne et sociale des patients insuffisants respiratoires chroniques sévères pris en charge dans le réseau ANTADIR

INTRODUCTION

Chronic respiratory failure (CRF) has an impact on quality of life because of respiratory handicap.

METHODS

The purpose of this study was to analyse the daily life and social activities of patients with CRF. A questionnaire was addressed to over 9000 patients being cared for in the ANTADIR homecare network, with over a 60% response rate.

RESULTS

The data showed that patients were old, and frequently had comorbidity. The predominant diagnosis was chronic obstructive airways disease (COPD) and the number of women in this population continues to increase. Respiratory handicap led to a loss of autonomy, a reduction in social activity and mobility of patients, but the impact differed markedly according to the cause of the respiratory failure, as well as age and social class. A typological study of behavioural characteristics revealed three groups of patients with contrasting profiles.

CONCLUSION

These results lead to recommendation for better management of social aspects of patient care in the ANTADIR network.

Oxygen therapy during exercise training in chronic obstructive pulmonary disease

BACKGROUND

Exercise training within the context of pulmonary rehabilitation improves outcomes of exercise capacity, dyspnea and health-related quality of life in individuals with chronic obstructive pulmonary disease (COPD). Supplemental oxygen in comparison to placebo increases exercise capacity in patients performing single-assessment exercise tests. The addition of supplemental oxygen during exercise training may enable individuals with COPD to tolerate higher levels of activity with less exertional symptoms, ultimately improving quality of life.

OBJECTIVES

To determine how supplemental oxygen in comparison to control (compressed air or room air) during the exercise-training component of a pulmonary rehabilitation program affects exercise capacity, dyspnea and health-related quality of life in individuals with COPD.

SEARCH STRATEGY

All records in the Cochrane Airways Group Specialized Register of trials coded as 'COPD' were searched using the following terms: (oxygen* or O2*) AND (exercis* or train* or rehabilitat* or fitness* or physical* or activ* or endur* or exert* or walk* or cycle*). Searching the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, EMBASE and CINAHL databases identified studies. The last search was carried out in June 2006.

SELECTION CRITERIA

Only randomized controlled trials (RCTs) comparing oxygen-supplemented exercise training to non-supplemented exercise training (control group) were considered for inclusion. Participants were 18 years or older, diagnosed with COPD and did not meet criteria for long-term oxygen therapy. No studies with mixed populations (pulmonary fibrosis, cystic fibrosis, etc) were included. Exercise training was greater than or equal to three weeks in duration and included a minimum of two sessions a week.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion in the review and extracted data. Weighted mean differences (WMD) with 95% confidence intervals (CI) were calculated using a random-effects model. Missing data were requested from authors of primary studies.

MAIN RESULTS

Five RCTs met the inclusion criteria. The maximum number of studies compared in the meta-analysis was three (31 on oxygen versus 32 control participants), because all included studies did not measure the same outcomes. When two studies were pooled, statistically significant improvements of oxygen-supplemented exercise training were found in constant power exercise time, WMD 2.68 minutes (95% CI 0.07 to 5.28 minutes). Supplemental oxygen increased the average exercise time from 6 to 14 minutes; the control intervention increased average exercise time from 6 to 12 minutes. Constant power exercise end-of-test Borg score (on a scale from 1 to 10) also showed statistically significant improvements with oxygen-supplemented exercise training, WMD -1.22 units (95% CI -2.39 to -0.06). One study showed a significant improvement in the change of Borg score after the shuttle walk test, by -1.46 units (95% CI -2.72 to -0.19). There were no significant differences in maximal exercise outcomes, functional exercise outcomes (six-minute walk test), shuttle walk distance, health-related quality of life or oxygenation status. According to the GRADE system most outcomes were rated as low quality because they were limited by study quality.

AUTHORS' CONCLUSIONS

This review provides little support for oxygen supplementation during exercise training for individuals with COPD, but the evidence is very limited. Studies with larger number of participants and strong design are required to permit strong conclusions, especially for functional outcomes such as symptom alleviation, health-related quality of life and ambulation.

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

BACKGROUND

The adherence to the prescribed oxygen therapy is difficult to obtain for patients on long-term oxygen therapy (LTOT). There is little information on the modalities of oxygen utilisation for patients on LTOT who are using liquid oxygen in real life.

STUDY OBJECTIVE

Evaluation of the behaviour and the knowledge regarding LTOT in a large group of patients mainly using liquid oxygen.

DESIGN AND SETTING

Questionnaire administered to consecutive outpatients on domiciliary LTOT for at least 6 months referring to one of 20 clinics throughout Italy. Blinded to this result, the physician who cared for the patient completed another questionnaire.

RESULTS

We evaluated 1504 patients (mean age 71.6 years; males 64%; 74% suffering from COPD). Most respondents (93%) used liquid oxygen with mobile device. Fifteen per cent of patients had a prescribed length of oxygen therapy less than 15 h/day; 21% reported to practice oxygen for less than 15 h/day. Patients reported using oxygen for less hours than had been prescribed during the day at rest (P=0.02, k=0.80) during exercise (P=0.002, k=0.72) and at night (P=0.0036, k=0.77). There was no difference between the flow prescribed by the physician and that known and practised by the patient at rest or during sleep; during exercise the flow reported by patients was lower than that prescribed by the physician. Patients used in the night but not at rest or during exercise, a lower level of oxygen flow than what they knew had been prescribed. Fifty-five per cent of patients received indications to modify the oxygen flow in the various situations of life. Liquid oxygen was almost always useful to decrease breathlessness. Most (84%) patients possessed a mobile device, but only 40% declared they used it daily, 'shame' being indicated as the principal barrier. On the physicians' side, we found that the criteria used in prescribing did not always correspond to evidence-based recommendations.

CONCLUSION

The widespread use of liquid oxygen did not automatically assure optimal adherence to the prescribed treatment as regards times and modality of oxygen use. A better education of patients, relatives, and the general public, as well as increased self-assessment on the part of health caregivers would improve the practice of LTOT in Italy.

Outcomes of adult domiciliary oxygen therapy in pulmonary diseases

Domiciliary oxygen therapy has been used during the last five decades to alleviate hypoxemia and its consequences. It is considered to be one of the most expensive therapeutic methods currently available, but it is also the only therapeutic approach that can prolong survival in patients with chronic hypoxemia. Domiciliary oxygen therapy is also aimed at relieving dyspnea and improving exercise capacity and sleep quality. Portable cylinders, concentrators and portable liquid systems are the main delivery systems currently available and oxygen-conserving devices attached are aimed at improving their effectiveness. In order to minimize the associated costs, appropriate patient selection and reassessment are required. Domiciliary oxygen therapy is mostly prescribed in chronic obstructive pulmonary disease - a disease caused predominantly by smoking and in which airway obstruction results in reduced arterial oxygenation (hypoxemia). Domiciliary oxygen therapy effectiveness is best evaluated and documented in chronic obstructive pulmonary disease, which also accounts for most of its prescriptions. Therefore, this review focuses predominantly on this disease-related oxygen therapy.

Perturbação respiratória durante o sono em doença pulmonar obstrutiva crônica

A doença pulmonar obstrutiva crônica é uma condição freqüente e é hoje a quarta principal causa de mortes nos Estados Unidos. A prevalência de perturbação respiratória durante o sono, ou síndrome de superposição, como anteriormente denominada, ainda não foi determinada devido à publicação de relatos conflitantes. Esta condição deve continuar sendo investigada devido aos efeitos adversos causados por transtornos respiratórios relacionados ao sono em pacientes com doença pulmonar de base. Neste relato, discutiremos brevemente os mecanismos envolvidos na origem da perturbação respiratória durante o sono em doença pulmonar obstrutiva crônica e auxiliaremos o leitor a distinguir àqueles pacientes que se beneficiariam de uma avaliação do padrão do sono mais detalhada, com a discussão de tópicos de gerenciamento e opções de tratamento.

Continuous Oxygen Therapy for Hypoxic Pulmonary Disease

Continuous oxygen therapy (COT) has become widely accepted in the last 20 years in patients with continuous hypoxemia. This review focuses on guidelines for COT, adherence to these guidelines, and the effect of COT on survival, hospitalization, and quality of life. Guidelines for COT are mainly based on three randomized studies where documentation of hypoxemia (P(a)O2 <60mm Hg) and administration of oxygen at least 15 hours/day, are essential. There is less certainty concerning the required correction for hypoxemia, the attitude against current smokers with hypoxemia, the frequency and methods of follow up, and the effect of prescribing domiciliary oxygen to patients with temporary hypoxemia due to a clinically unstable condition (i.e. short-term oxygen therapy [STOT]). The administration of COT to patients with hypoxemic conditions other than COPD rests on extrapolation of data from COPD patients in the NOTT (Nocturnal Oxygen Therapy Trial) and MRC (British Medical Research Council) studies. Adherence to these guidelines is low in general, and very low in some cases. In some countries, STOT accounts for the majority of all prescriptions of domiciliary oxygen, and because nearly half of these patients do not meet the hypoxemia criteria at 3-month follow-up, re-evaluation is mandatory. Only 35%, approximately, of the patients are followed up, and this is one of the main reasons for poor adherence to the hypoxemia criteria. In order to improve the quality of surveillance of COT, more effort has to be put into education of the patients and staff responsible for COT, centralization of the domiciliary organizations, better equipment for ambulation and traveling, and regular follow-up preferably with home visits. The role of an oxygen register on the quality of surveillance of COT has to be determined. The beneficial effect of COT on survival is well established, and some evidence suggests that COT reduces hospitalization. It appears that ambulatory oxygen from liquid source or lightweight cylinders improves disease-specific quality of life modestly in selected patients who partake in regular outdoor activity. Whether COT from oxygen concentrators improves quality of life significantly is, at present, less clear.

Long-term oxygen therapy stops the natural decline of endurance in COPD patients with reversible hypercapnia

BACKGROUND

Respiratory muscle weakness is one of the most important causes of hypercapnia in patients with COPD. There is evidence that stable hypercapnic patients will benefit from long-term oxygen therapy (LTOT).

OBJECTIVES

The prognostic role of reversible hypercapnia in COPD is still unclear. Early implementation of LTOT in these patients may influence endurance time and mortality.

METHODS

In this pilot study, we investigated 28 patients (26 males, 49-74 years) with COPD, advanced airflow limitation [forced expiratory volume in 1 s (percentage of predicted value) 40.8 +/- 10.2] and mild hypoxaemia (pO(2) 66.5 +/- 6.3 mm Hg). All patients had developed a moderate reversible hypercapnia during an acute exacerbation or during exercise testing (peak pCO(2) 48.0 +/- 2.5 mm Hg). Patients were allocated randomly to a control group (n = 14) or an LTOT group (n = 14). The two groups were well matched in terms of physiological data. Lung function, endurance time (cycle ergometer), dyspnoea score, blood gases and LTOT compliance were measured at baseline and every 6 months over a period of 3 years.

RESULTS

Endurance time increased from 6.4 +/- 2.7 min at baseline to 7.1 +/- 2.7 min after 1 year in the LTOT group and decreased from 6.1 +/- 3.0 to 4.9 +/- 3.8 min in the controls (p < 0.05). After 1 year, the end-exercise dyspnoea score was significantly lower in the LTOT group (4.5 +/- 1.5) than in the controls (5.7 +/- 1.9).

CONCLUSION

COPD patients with reversible hypercapnia and mild hypoxaemia benefit from LTOT in terms of endurance time and a reduction of exertional dyspnoea after 1 year.

IRAD2 : Insuffisant respiratoire à domicile 2 (2e étude) effets d’une réhabilitation à domicile chez l’insuffisant respiratoire chronique dénutri

STATE OF THE ART

The IRAD2 trial is evaluating a 3-month home intervention which includes education, oral supplements, exercise and androgenic steroids in undernourished patients with chronic respiratory failure. The main objective is to increase the six-minute walking distance by more than 50 m with an improvement in health-related quality-of-life. Secondary end-points include a reduction in exacerbation rates by 25%, a reduction in health-related costs and an increase in survival during the year following intervention.

MATERIAL AND METHODS

This interventional, multi-centre, prospective, two-armed parallel, controlled trial is being conducted in 200 patients. In both groups, "Control" and "Rehabilitation", 7 home visits are scheduled during the 3-month intervention for education purpose. In the "Rehabilitation" group, patients will receive 160 mg/d of oral testosterone undecanoate in men, 80 mg/d in women, oral dietary supplements (563 kcal/d) and exercises on an ergometric bicycle 3 to 5 times a week.

EXPECTED RESULTS

In the event of significant responses to intervention, this trial would validate a comprehensive and global home-care for undernourished patients with chronic respiratory failure combining therapeutic education, oral supplements, androgenic substitution and physical activity.

The relative survival of COPD patients on long-term oxygen therapy in Australia: A comparative study

OBJECTIVE

The survival of patients with COPD on long-term oxygen therapy (LTOT) has been studied using both univariate and multivariate procedures. There has been only one previous report of relative survival. Relative survival takes into account the risk of death due to increasing age. The objective of this study was to determine the relative survival of a group of South Australian patients prescribed home oxygen therapy for COPD.

METHODOLOGY

A method proposed by Hakulinen was used to determine relative survival. The results were compared with the relative survival of a similar group of French COPD patients.

RESULTS

A total of 505 COPD patients (249 males, 256 females) were included in the survival analysis. Relative survival corrected for life expectancy was 78.1%, 56.7%, 23.1% and 1.1% at 1, 2, 5 and 10 years, respectively, which was less than that reported in a recent French study of comparable patients. Our patients were similar with respect to age, severity of hypoxaemia and oxygen usage to those in the French study.

CONCLUSIONS

Using relative survival analysis, Australian LTOT patients with COPD have worse outcomes than some European patients. Factors contributing to the excess mortality in South Australian COPD patients need to be investigated.

Effects of almitrine bismesylate on arterial blood gases in patients with chronic obstructive pulmonary disease and moderate hypoxaemia: a multicentre, randomised, double-blind, placebo-controlled study

BACKGROUND

Advanced chronic obstructive pulmonary disease (COPD) generates high costs, especially when patients require domiciliary long-term oxygen therapy (LTOT). Almitrine bismesylate has been shown to improve gas exchange in the lungs. Our hypothesis was that long-term treatment with almitrine might postpone the prescription of LTOT.

OBJECTIVE

To evaluate the effects of almitrine sequential treatment on arterial blood gases in COPD patients with moderate hypoxaemia.

METHODS

COPD patients with moderate hypoxaemia [partial oxygen tension in arterialised blood (PaO(2)) between 7.33 and 8.66 kPa (56-65 mm Hg)] were investigated. After a 1-month run-in period, patients were given either almitrine 100 mg per day or placebo for sequential treatment for a total of 12 months.

RESULTS

115 patients in a steady state (57 in the almitrine and 58 in the placebo group) were included. Mean age was 60 years, mean forced expiratory volume in 1 s was 34 +/- 13% of predicted and mean PaO(2) was 8.04 +/- 0.5 kPa (60.5 +/- 3.8 mm Hg). 38 patients were lost to follow-up, 23 in the almitrine and 15 in the placebo group. The majority of drop-outs were due to adverse events (AE; 16 in the almitrine and 9 in the placebo group). Almitrine treatment resulted in PaO(2) improvement of 0.43 +/- 0.88 kPa (3.2 +/- 6.6 mm Hg) (p = 0.003). The treatment effect between almitrine and placebo was 0.45 kPa (3.4 mm Hg) (p = 0.003). In the almitrine group, two distinct subgroups were observed: responders (n = 19) and non-responders (n = 38). Almitrine treatment in responders resulted in a clinically significant improvement in PaO(2) of 1.36 +/- 0.7 kPa (10.2 +/- 5.3 mm Hg) (p < 0.0001) and a reduction of partial carbon dioxide tension in arterialised blood. 31 patients experienced serious AE: 17 in the almitrine and 14 in the placebo group. Five patients died during the study (3 in the almitrine and 2 in the placebo group). Most AE occurring during the study were related to underlying disease. Clinical diagnosis of polyneuropathy resulted in the withdrawal of 5 patients in the almitrine group and 3 patients in the placebo group. Four patients in the almitrine group experienced weight loss.

CONCLUSIONS

Almitrine treatment of patients with severe COPD and moderate hypoxaemia resulted in a small but significant improvement in PaO(2) over 12 months. A clinically important improvement in gas exchange was observed in 33% of treated patients. These patients may be candidates for long-term treatment.

Benefits of oxygen on exercise performance and pulmonary hemodynamics in patients with COPD with mild hypoxemia

STUDY OBJECTIVES

To clarify the effects of oxygen on exercise performance and pulmonary hemodynamics during exercise in patients with COPD with mild hypoxemia at rest.

DESIGN

Seventy-five male patients with stable COPD ("pink puffer" type), accompanied by mild hypoxemia (> 60 mm Hg) at rest and with mild (percentage of predicted FEV1 [%FEV1] > 50%, n = 16), moderate (%FEV1 > 35% to < or = 50%, n = 25), and severe (%FEV1 < or =35%, n = 34) airflow obstruction were recruited from an outpatient clinic. A 6-min walking distance (6MD) test was administered to 75 patients, and the pulmonary hemodynamics of 43 subjects were determined during exercise on a supine bicycle ergometer at 25 W and breathing compressed air and oxygen at 2 L/min.

RESULTS

Supplemental oxygen resulted in a significant increase in 6MD, except for patients with mild airflow obstruction and mild desaturation. This increase in 6MD produced by oxygen was greater as the restriction of the airflow was more severe, and correlated negatively with %FEV1, but not with PaO2 at rest or exercise hypoxemia. Pulmonary artery pressure (Ppa) and pulmonary artery occlusion pressure (Pop) increased with exercise, while the rates of increase in both types of pressure were significantly higher for severe COPD than for mild COPD and moderate COPD. Oxygen inhalation significantly reduced the increases in Ppa and Pop during exercise in patients with moderate-to-severe COPD, and the effect of oxygen on the increase in Pop correlated positively with airtrapping (vital capacity - FVC).

CONCLUSION

These findings suggest that supplemental oxygen benefits patients with COPD with moderate-to-severe airflow obstruction and mild hypoxemia at rest, as reflected in improvement in exercise performance and pulmonary hypertension during exercise.

Are COPD patients with nocturnal REM sleep-related desaturations more prone to developing chronic respiratory failure requiring long-term oxygen therapy?

BACKGROUND

Nocturnal oxygen desaturations (NOD), especially during REM sleep, have been described in patients with COPD. However, the role of NOD in the evolution of COPD to chronic respiratory failure has not been well studied.

OBJECTIVE

The aim of our study was to evaluate whether NOD is a risk factor for the development of chronic respiratory failure in COPD patients.

METHODS

We studied 34 consecutive COPD patients with a stable daytime PaO(2) >60 mm Hg over a period of 42 months. We classified patients as desaturators (NOD) when episodic desaturations were found mainly during REM sleep, independently of baseline SaO(2) values.

RESULTS

At enrollment 19 patients (55.8%) had NOD. Over the follow-up period, 10 patients (29.4%) were included in a long-term oxygen therapy (LTOT) programme (9 were desaturators). The LTOT was initiated a median time of 22 +/- 6.8 months after enrollment. Patients who were subsequently prescribed LTOT had lower values of FEV(1) at enrollment, with a higher degree of NOD and PaCO(2). Stable respiratory failure developed earlier in patients with NOD: the two enrollment curves for LTOT differed significantly (log-rank test 2.56, p = 0.005). PaCO(2), NOD and FEV(1) were statistically significantly associated, both in univariate and multivariate Cox proportional hazards analyses, with an increased risk of entering a LTOT programme.

CONCLUSIONS

We conclude that NOD may represent an independent risk factor for the development of chronic respiratory failure in COPD patients with daytime PaO(2) >60 mm Hg. A larger study is needed to confirm the role of NOD in the natural history of COPD and subsequently to identify the most appropriate therapeutic approach.

Clinical course and prognosis of patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a basically benign disease, but the prognosis is so poor that the mortality rate is similar to some malignant diseases. Depending on the disease severity, the 5-year mortality rate of patients with COPD varies from 40 to 70%. The three major causes of death have been identified as COPD itself, lung cancer, and cardiovascular disease. The following factors have been reported to be related to survival: FEV1 (especially the maximal attainable lung function), age, gender, PaO2, PaCO2, body weight, and comorbidity. There have been several large-scale randomized clinical trials to examine the prophylactic effects of inhaled anti-cholinergics and inhaled corticosteroids on the annual decline in FEV1. However, unfortunately, in all of the published studies, these drugs had no effect on the annual decline in FEV1.

[High prevalence of long-term domiciliary oxygen therapy with a low percentage of inappropriate prescription in the Madrid health care area. Evaluation of the correct use]

The efficacy of long-term domiciliary oxygen therapy (DOT) has been confirmed in patients who comply with guidelines; however, the prevalence in different populations varies greatly although no satisfactory explanation has been found for this.

OBJECTIVES

To assess the prevalence of inappropriate use of DOT in the health care area of the Community of Madrid, where demographic and health care features are well-defined.

MATERIAL AND METHODS

Descriptive, transversal population study enrolling all patients with DOT in our health care area over a period of one year (May 1995 to Mayo 1995). Inappropriate use was defined as characterized by at least one of the following conditions: inappropriate prescription, poor compliance or continued smoking.

RESULTS

The total number of patients was 860, the prevalence of DOT use being 178.3 per 100,000 inhabitants for the period. Ninety-three refused to participate. Nearly half the patients ha been using oxygen therapy for over two years. Seventy percent were followed by pneumologists. Seventy-four percent were men, with a mean age of 70 +/- 9 yr. Criteria for prescription were not followed in 9.7% of the cases. Chronic obstructive pulmonary disease was the reason for prescribing DOT in 59.7%. Use was appropriate in 719 cases. Use was inappropriate in 337 (46.9%), related to poor compliance in 60.5%, current smoking in 11%, and inappropriate prescription in 5.6% and for more than one criterion in 22.8%.

CONCLUSIONS

The prevalence of DOT use in our health care area is very high. The percentage of inappropriate use is high, although similar to that of other populations, and highly related to poor compliance. The percentage of inappropriate prescription is low. Possible reasons for the high prevalence are discussed.

Predictors of nocturnal oxygen desaturation in patients with COPD

The aim of this study was to identify factors which might predict nocturnal desaturation (defined as a fall of > 4% from awake baseline level for > or = 5 min) in normoxic or mildly hypoxic patients with stable COPD [arterial O2 saturation (SaO2) > or = 91%]. The study was prospective in nature, had full ethical approval and was performed in the Respiratory Department of a city teaching hospital. Thirty-three patients [mean (SD) age 67.2 (9) years] with stable COPD [mean (SD) FEV1 36.8 (11.0)% pred.] were recruited via the respiratory outpatient clinics and through the respiratory wards. The following parameters were measured: daytime arterial blood gases; spirometry; lung volumes (helium dilution); single breath CO transfer factor (TLCO and KCO); maximum inspiratory (IMP) and expiratory mouth pressures; pulse oximetry (SpO2) across a 6-min walk test, and SpO2 during sleep. Seventeen patients who experienced nocturnal desaturation had significantly lower mean PaO2 and SaO2, and higher PaCO2 values compared to non-desaturators. There was a positive correlation between mean nocturnal SpO2 and daytime PaO2, SaO2, and minimum exercise SpO2, and a negative correlation between mean nocturnal SpO2 and PaCO2, and FRC. Regression analysis revealed that daytime SaO2 was the only independent predictor of mean nocturnal saturation (accounting for 61% of the variability in the mean nocturnal SpO2). We observed nocturnal desaturation in all patients with a daytime SaO2 < or = 93% but in no patient with SaO2 > or = 95%. We conclude that daytime SaO2 can be used to predict nocturnal desaturation in normoxic or mildly hypoxic patients with stable COPD. Nocturnal desaturation is likely in patients with COPD where daytime SaO2 < or = 93%, and unlikely where daytime SaO2 > or = 95%.

Effects of long-term oxygen therapy in patients with chronic obstructive pulmonary disease

Long-term oxygen therapy is largely used in the management of severe hypoxemia in patients with chronic obstructive pulmonary disease. It was demonstrated that long-term oxygen therapy prolongs life, prevents progression of hypoxic pulmonary hypertension, and controls polycythemia. Recent data suggest that in patients with moderate hypoxemia (Pao2 > 55 mm Hg), long-term oxygen therapy does not prolong life. Life expectancy in those patients seems to depend on the severity of airway obstruction. Long-term oxygen therapy improves cognitive functions and emotional status. There is some evidence suggesting that it also improves quality of life, but more data are needed. There are conflicting data concerning the rationale for nocturnal oxygen supplementation in patients with arterial blood desaturation during sleep.