Use of a real-time microbial air sampler for operational cleanroom monitoring.

A sampler that detects and counts viable particles in the air of cleanrooms in real-time was studied. It was found that when the sampler was used to monitor airborne particles dispersed from a number of materials used in cleanrooms, including garments, gloves, and skin, the number of viable particles dispersed from these materials was greater than anticipated. It was concluded that a substantial proportion of these viables were of a non-microbiological origin. When the sampler was used to monitor a non-unidirectional airflow cleanroom occupied by personnel wearing cleanroom garments, it was found that the airborne viable concentrations were unrealistically high and variable in comparison to microbe-carrying particles simultaneously measured with efficient microbial air samplers. These results confirmed previously reported ones obtained from a different real-time sampler. When the real-time sampler was used in a workstation within the same cleanroom, the recorded viables gave results that suggest that the sampler may provide an effective airborne monitoring method, but more investigations are required. LAY ABSTRACT: The airborne concentrations measured by a real-time microbial air sampler within an operational, non-unidirectional airflow cleanroom were found to be unrealistically high due to a substantial numbers of particles of non-microbiological origin. These particles, which resulted in false-positive microbial counts, were found to be associated with a number of materials used in cleanrooms. When the sampler was used within a cleanroom workstation, the counts appeared to be more realistic and suggest that this type of real-time airborne microbial counter may provide a useful monitoring method in such workstations, but further investigations are required.

Deletion variant in the ADRA2B gene increases coupling between emotional responses at encoding and later retrieval of emotional memories.

A deletion variant of the ADRA2B gene that codes for the α2b adrenoceptor has been linked to greater susceptibility to traumatic memory as well as attentional biases in perceptual encoding of negatively valenced stimuli. The goal of the present study was to examine whether emotional enhancements of memory associated with the ADRA2B deletion variant were predicted by encoding, as indexed by the subjectively perceived emotional salience (i.e., arousal) of events at the time of encoding. Genotyping was performed on 186 healthy young adults who rated positive, negative, and neutral scenes for level of emotional arousal and subsequently performed a surprise recognition memory task 1 week later. Experience of childhood trauma was also measured, as well as additional genetic variations associated with emotional biases and episodic memory. Results showed that subjective arousal was linked to memory accuracy and confidence for ADRA2B deletion carriers but not for non-carriers. Our results suggest that carrying the ADRA2B deletion variant enhances the relationship between arousal at encoding and subsequent memory for moderately arousing events.

Compression versus sclerotherapy for patients with isolated refluxing reticular veins and telangiectasia: a randomized trial comparing quality-of-life outcomes.

OBJECTIVE: To prospectively study quality-of-life (QoL) benefits comparing compression stockings to sclerotherapy in subjects with symptomatic reticular veins and telangiectasia. METHODS: Fifty-eight consecutive female patients with normal saphenous and deep venous systems and venous dysfunction score (VDS) ≥ 4 were randomized to either sclerotherapy (N = 29) or thigh high 20-30 mmHg compression stockings (N = 29). Following a trial of compression, subjects in the compression arm were eligible to crossover to the sclerotherapy arm. Patient-reported QoL data were acquired using a modified Aberdeen Varicose Vein Questionnaire in five stages, initial severity (T0), following compression trial (T1), after reticular vein sclerotherapy (T2), approximately three months after sclerotherapy for telangiectasia (T3) and the 12-month mark (T4). RESULT: For patients in the compression arm, four key symptoms including aching, pain, leg cramps and restlessness were significantly reduced, while patients in the sclerotherapy arm of treatment reported broad symptom relief in all key symptoms assessed. CONCLUSION: Isolated refluxing reticular and telangiectatic vein disease may cause QoL impairment in select patients and represent far more than a cosmetic concern. Compression therapy offers relief of aching, pain, leg cramping and restlessness in patients with isolated refluxing reticular veins and telangiectasia. Sclerotherapy of reticular veins offers a statistically superior broad spectrum relief of symptoms, while additional sclerotherapy of residual telangiectasia in this cohort demonstrated additive relief of aching and pain. Symptom assessments at 12 months suggest ongoing symptom relief following sclerotherapy.

Age related decreases in thermoregulation and cardiovascular function in horses.

REASON FOR PERFORMING STUDY: Older horses have an increased risk of hyperthermia due to impaired cardiovascular function. While many studies have investigated thermoregulation in horses during exercise, none have investigated the effects of ageing. OBJECTIVE: To test the hypothesis that there is a difference in thermoregulation during exercise and plasma volume (PV) in young and old horses. METHODS: Study 1: 6 young (Y, 7.7 ± 0.5 years) and 5 old (O, 26.0 ± 0.8 years) unfit Standardbred mares (507 ± 11 kg, mean ± s.e.) ran on a treadmill (6% grade, velocity calculated to generate a work rate of 1625 watts) until core temperature reached 40 °C. Core (CT), skin (ST), rectal temperature (RT) and heart rate (HR) were measured every min until 10 min post exertion. Packed cell volume (HCT), lactate (LA) and plasma protein (TP) were measured in blood samples collected before, at 40 °C and every 5 min until 10 min post exercise. Sweat loss was estimated using bodyweight. Study 2: Plasma volume was measured in 26 young (8.2 ± 0.7 years) and 8 old (26.6 ± 0.7 years) Standardbred mares (515 ± 12 kg) using Evans Blue dye. Pre-exercise blood (rBV) and red cell (rRCV) volumes were calculated using PV and HCT. Data analysis utilised repeated measures ANOVA and t tests and data are expressed as mean ± s.e. RESULTS: Old horses reached 40 °C faster (998 ± 113 vs. 1925 ± 259 s; P < 0.05) with a greater HR at 40 °C (184 ± 6 vs. 140 ± 5 beats/min; P < 0.05) and greater sweat losses (P < 0.05). Heart rate did not differ (P > 0.05) post exercise. Age did not alter (P > 0.05) CT, ST, RT, LA, HCT or TP. Plasma volume was greater in Y vs. O horses (P < 0.05, 28.5 ± 1.4 vs. 24.1 ± 1.6 l) as was rBV (41.3 ± 2.0 vs. 35.3 ± 2.3 l) and rRCV (13.3 ± 0.6 vs. 11.1 ± 0.8 l). CONCLUSION: Ageing compromises the ability to handle the combined demand of exercise and thermoregulation in part due to decreased absolute pre-exercise PV.

Potential benefits of statins on morbidity and mortality in chronic obstructive pulmonary disease: a review of the evidence.

Studies show reduced forced expiratory volume in 1 s (FEV(1)) in patients with chronic obstructive pulmonary disease (COPD) is an important independent predictor of cardiovascular death and is characterised by both pulmonary and systemic inflammation. Evidence shows statins have important anti-inflammatory effects in both the lungs and arteries. Although randomised control trials are yet to be reported, non-randomised studies have consistently shown benefit in COPD patients taking statins compared with those not. These include reductions in both cardiovascular and respiratory morbidity/mortality. Other potential benefits include a reduced decline in FEV(1) and reduced risk of lung cancer. It is argued that confounding by a "healthy user effect" is unlikely to explain the observed benefit. Given the undisputed benefit of statins in high risk populations and the growing body of data suggesting statins may benefit patients with COPD, the question arises "Should statins be considered more often in patients with COPD?".

Isolated nocturnal desaturation in COPD: prevalence and impact on quality of life and sleep.

BACKGROUND AND AIMS: The clinical impact of nocturnal desaturation on health related quality of life (HRQL) and sleep in chronic obstructive pulmonary disease (COPD) has been little studied. The aim of this study was to evaluate the prevalence and clinical impact of nocturnal desaturation in a typical outpatient population with COPD. PATIENTS AND METHODS: Between 2002 and 2005, consecutive patients with COPD attending outpatient services at the study centre underwent resting oximetry if they were not on domiciliary oxygen therapy. If their resting saturations were less than 95%, overnight pulse oximetry was performed. Significant nocturnal desaturation was defined as spending more than 30% of at least one of two nights with a saturation of less than 90%. The Chronic Respiratory Questionnaire (CRQ) and Short Form 36 (SF36) were used to assess HRQL, and the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Score (ESS) and Functional Outcomes of Sleep (FOSQ) questionnaires were used to assess sleep quality and daytime function. RESULTS: Of 1104 patients, 803 underwent resting oximetry and 79 had resting oxygen saturations of less than 95%. Of these, 59 agreed to undergo overnight oximetry (mean age 70 years, forced expiratory volume in 1 s 37.2% predicted, resting Po(2) on air 8.9 kPa). Significant nocturnal desaturation was seen in 29 (49.2%) of the 59 subjects. Assuming the less hypoxic patients do not have nocturnal desaturation, the prevalence of nocturnal desaturation in the whole clinic population could be estimated at 4.8%. There were no significant differences in CRQ, SF36, PSQI, ESS or FOSQ scores for desaturators compared with non-desaturators. CONCLUSION: Significant nocturnal desaturation was common in patients with COPD with resting saturations of less than 95%, but was estimated to have a prevalence of less than 5% in the whole outpatient population. Nocturnal desaturation was not associated with impairment of HRQL, sleep quality or daytime function.

Pharmacological actions of statins: potential utility in COPD.

Chronic obstructive pulmonary disease (COPD) is characterised by minimally reversible airflow limitation and features of systemic inflammation. Current therapies for COPD have been shown to reduce symptoms and infective exacerbations and to improve quality of life. However, these drugs have little effect on the natural history of the disease (progressive decline in lung function and exercise tolerance) and do not improve mortality. The anti-inflammatory effects of statins on both pulmonary and systemic inflammation through inhibition of guanosine triphosphatase and nuclear factor-κB mediated activation of inflammatory and matrix remodelling pathways could have substantial benefits in patients with COPD due to the following. 1) Inhibition of cytokine production (tumour necrosis factor-α, interleukin (IL)-6 and IL-8) and neutrophil infiltration into the lung; 2) inhibition of the fibrotic activity in the lung leading to small airways fibrosis and irreversible airflow limitation; 3) antioxidant and anti-inflammatory (IL-6 mediated) effects on skeletal muscle; 4) reduced inflammatory response to pulmonary infection; and 5) inhibition of the development (or reversal) of epithelial-mesenchymal transition, a precursor event to lung cancer. This review examines the pleiotropic pharmacological action of statins which inhibit key inflammatory and remodelling pathways in COPD and concludes that statins have considerable potential as adjunct therapy in COPD.

Forced expiratory volume in one second: not just a lung function test but a marker of premature death from all causes.

The clinical utility of spirometric screening of asymptomatic smokers for early signs of air flow limitation has recently come under review. The current authors propose that reduced forced expiratory volume in one second (FEV(1)) is more than a measure of airflow limitation, but a marker of premature death with broad utility in assessing baseline risk of chronic obstructive pulmonary disease (COPD), lung cancer, coronary artery disease and stroke, collectively accounting for 70-80% of premature death in smokers. Reduced FEV(1) identifies undiagnosed COPD, has comparable utility to that of serum cholesterol in assessing cardiovascular risk and defines those smokers at greatest risk of lung cancer. As such, reduced FEV(1) should be considered a marker that identifies smokers at greatest need of medical intervention. Smoking cessation has been shown to attenuate FEV(1) decline and, if achieved before the age of 45-50 yrs, may not only preserve FEV(1) within normal values but substantially reduce cardiorespiratory complications of smoking. Recent findings suggest inhaled drugs (bronchodilators and corticosteroids), and possibly statins, may be effective in reducing morbidity and mortality in patients with chronic obstructive pulmonary disease. The current authors propose that spirometry has broad utility in identifying smokers who are at greatest risk of cardiorespiratory complications and greatest benefit from targeted preventive strategies, such as smoking cessation, prioritised screening and effective pharmacotherapy.

A randomized evaluation of the acute efficacy, acceptability and tolerability of flutter and active cycle of breathing with and without postural drainage in non-cystic fibrosis bronchiectasis.

Airway clearance is integral to the management of bronchiectasis, yet there is no evidence as to the optimal modality. The aim of this randomized prospective study was to evaluate the acute efficacy, acceptability and tolerability of three airway clearance techniques in non-cystic fibrosis (non-CF) bronchiectasis. Flutter, active cycle of breathing technique (ACBT) and ACBT with postural drainage (ACBT-PD) were evaluated in random order over a week in 36 patients (mean age 62 years, range 33-83), with stable non-CF bronchiectasis. Total sputum wet weight for ACBT-PD was twice that of either ACBT alone or Flutter. No objective difference in treatment duration was noted. All three techniques were well accepted and tolerated. Patient preference was 16 (44%) for Flutter, eight (22%) ACBT and 12 (33%) for ACBT-PD. Patient demography, factors such as upper airways or reflux symptoms, previous use or acute efficacy did not predict preference. This is the first randomized systematic evaluation of acute efficacy, acceptability and tolerability of Flutter, ACBT and ACBT-PD in non-CF bronchiectasis. All three techniques were well tolerated but ACBT-PD proved superior in terms of acute efficacy. Patient preference for treatment modality could not be predicted.

Overnight prescription of oxygen in long term oxygen therapy: time to reconsider the guidelines?

BACKGROUND: Guidelines for long term oxygen therapy (LTOT) recommend increasing oxygen flow by 1 l/min overnight. A study was undertaken in patients with COPD on LTOT to determine the prevalence of overnight desaturation if the usual oxygen flow rate is not increased at night, whether resting oxygen saturation predicts overnight desaturation, and whether overnight desaturation correlates with health related quality of life (HRQL) and sleep quality. METHODS: A cross sectional prospective study was performed on consecutive patients with COPD on LTOT attending our regional outpatient oxygen service. All patients fulfilled standard criteria for LTOT, had been established on LTOT at a flow to achieve resting oxygen saturations >90%, but had not been instructed to increase oxygen flow overnight. Overnight desaturation was defined as <90% for > or =30% of the night on either of two consecutive nights. HRQL was evaluated with the SF-36 Health Survey Questionnaire, Chronic Respiratory Questionnaire, and the Pittsburgh Sleep Quality Index. RESULTS: Thirty eight patients (63% men) of mean (SD) age 73.5 (8.04) years and mean (SD) forced expiratory volume in 1 second 0.77 (0.35) l were evaluated. Overnight desaturation occurred in six (16%; 95% CI 4 to 27). Desaturators had mean (SD) resting oxygen saturation on room air of 88 (4.2)% compared with 90 (4.1)% in non-desaturators (p = 0.15), and corrected saturations of 93 (2.0)% versus 94 (2.0)% (p = 0.18). HRQL and sleep quality were poor but did not differ between desaturators and non-desaturators. CONCLUSIONS: Most patients did not exhibit overnight desaturation despite not increasing their LTOT prescription overnight. These results challenge the recommendation of routinely increasing overnight oxygen flow in patients receiving LTOT.

Short-burst oxygen therapy for COPD patients: a 6-month randomised, controlled study.

Short-burst oxygen therapy (SBOT) remains widely advocated for patients with chronic obstructive pulmonary disease (COPD), despite a lack of supporting evidence. The aim of this randomised, double-blind, placebo-controlled, parallel group study was to determine whether SBOT improves health-related quality of life (HRQL) or reduces acute healthcare utilisation in patients discharged following an acute exacerbation of COPD. Consecutive patients were screened; 78 of 331 were eligible for randomisation to cylinder oxygen, cylinder air or usual care following discharge. Patients were elderly with high acute healthcare utilisation, forced expiratory volume in one second of <1 L and had dyspnoea limiting daily activity but were not hypoxaemic at rest. Over the 6-month study period, there were no significant differences between patient groups in HRQL (Chronic Respiratory Questionnaire (CRQ), 36-item Short-Form Health Survey, Hospital Anxiety and Depression Scale) except for CRQ emotion domain. There were no significant differences in acute healthcare utilisation. Time to readmission was greatest in the usual care group. Cylinder use was high initially, but rapidly fell to very low levels within weeks in both cylinder oxygen and air groups. In conclusion, the availability of short-burst oxygen therapy for chronic obstructive pulmonary disease patients discharged from hospital following an acute exacerbation did not improve health-related quality of life or reduce acute healthcare utilisation. These results provide no support for the widespread use of short-burst oxygen therapy.

The endurance shuttle walking test: a responsive measure in pulmonary rehabilitation for COPD patients.

BACKGROUND: The endurance shuttle walk test (ESWT) is a standardized externally controlled constant paced field test for the assessment of endurance capacity in chronic lung disease. The ESWT has been advocated as a simple, acceptable, repeatable and responsive outcome measure for COPD patients undergoing pulmonary rehabilitation, but has not been formally compared with the more commonly used field walking test, the six-minute walk (6MW). We aimed to determine: 1) the responsiveness of the ESWT in COPD patients attending a hospital-based pulmonary rehabilitation programme, and 2) to compare the responsiveness of the ESWT with the 6MW. METHODS: Consecutive COPD patients, referred for a standard 8 week pulmonary rehabilitation programme, were recruited. Outcome parameters studied at baseline and completion of rehabilitation programme (8 weeks) included spirometric lung volumes, resting oxygen saturation, breathlessness scored pre and post exercise (modified Borg dyspnoea score), 6MW, ESWT, health-related quality of life (Chronic Respiratory Questionnaire) and Hospital Anxiety and Depression (HAD) scale. The incremental shuttle was employed to predict VO2 peak; 85% VO2 peak was used to determine the walk speed for the ESWT. RESULTS: Twenty stable COPD patients (11 male), mean (SD), age 71, (9) FEV1 0.95 (0.51), resting SpO2 95% (2) 6MW distance (m) 351 (104) and ESWT distance (m) 313 (193) were studied. Three patients did not complete their rehabilitation programme. Following rehabilitation, there were significant improvements in 6MW, ESWT, total CRQ and anxiety domain (HAD). The 6MW distance increased by 17% (47 m 95%CI 3, 90), while the ESWT increased by 92% (302 m 95%CI 104, 501). CONCLUSION: The ESWT is a simple, acceptable and highly responsive outcome measure for COPD patients undergoing a pulmonary rehabilitation programme. The ESWT has potential advantages in that it may be more responsive than the 6MW.

Functional variants of antioxidant genes in smokers with COPD and in those with normal lung function.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is predominantly the consequence of chronic smoking exposure, but its development may be influenced by genetic variants that affect lung remodelling, inflammation, and defence from oxidant stress. A study was undertaken to determine whether genetic variants within genes encoding the antioxidant enzymes superoxide dismutase (SOD) and catalase may be associated with the development of impaired lung function. METHODS: In a case-control study, the allele and genotype frequencies of functional polymorphisms from SOD1 (CuZnSOD), SOD2 (MnSOD), SOD3 (extracellular SOD), and catalase (CAT) were compared in chronic smokers with normal lung function (resistant smokers) and in those with COPD. RESULTS: Significantly higher frequencies of the G allele and CG/GG genotype of the 213 SOD3 polymorphism were found in resistant smokers (odds ratios (ORs) 4.3 (95% CI 1.5 to 13.3) and 4.2, 95% CI 1.4 to 13.3), Bonferroni corrected p = 0.02 and p = 0.02, respectively) than in those with COPD. There were no differences between the COPD and resistant smokers for the SOD1, SOD2, or CAT polymorphisms tested. CONCLUSIONS: The 213Gly variant of the SOD3 gene may, through antioxidant or anti-inflammatory effects, confer a degree of resistance in some smokers to the development of COPD.

The Dartmouth COOP Charts: a simple, reliable, valid and responsive quality of life tool for chronic obstructive pulmonary disease.

The negative impact of chronic obstructive pulmonary disease (COPD) on health-related quality of life (HRQL) is substantial. Measurement of HRQL is increasingly advocated in clinical practice; traditional outcome measures such as lung function are poorly responsive. However many HRQL tools are not user-friendly in the clinic setting. Hence HRQL is often neglected. The Dartmouth Cooperative Functional Assessment Charts (COOP) have the requisite attributes of a tool suitable for routine clinical practice: they are simple, reliable, quick and easy to perform and score and well accepted. We aimed to determine the reliability, validity and responsiveness of the COOP in patients with significant COPD. HRQL was assessed during a prospective, randomised, placebo-controlled, double-blind, 12 week cross-over interventional study of ambulatory oxygen in patients (n = 50) with COPD. Test-retest reliability of the COOP domains was only modest however it was measured over a 2 month period. Significant correlations ranging between 0.4 and 0.8 were observed between all comparable domains of the COOP and the Medical Outcomes Study 36-item Short-form Health Survey, Chronic Respiratory Questionnaire (CRQ) and Hospital Anxiety and Depression (HAD) scale. Following ambulatory oxygen significant improvements were noted in all CRQ and HAD domains. Several domains of the generic SF-36 (role emotional, social functioning, role-physical) showed significant improvements. Comparable domains of the COOP (social activities, feelings) also showed significant improvements. The COOP change in health domain improved very significantly. The COOP is a simple, reliable HRQL tool which proved valid and responsive in our study population of COPD patients and may have a valuable role in routine clinical practice.

Long-term oxygen therapy improves health-related quality of life.

Guidelines for the prescription of long-term oxygen therapy (LTOT) in hypoxemic COPD patients are based on two landmark studies in which survival was the primary outcome. Such patients are importantly symptomatic with poor health-related quality of life (HRQL) but the effect of LTOT on HRQL remains uncertain. We undertook a prospective longitudinal interventional study of consecutive COPD patients referred to our regional oxygen service; n = 43 fulfilling criteria and commenced on LTOT, n = 25 not fulfilling criteria and continued on standard care. HRQL was measured at baseline, 2 and 6 months. Both patient groups had severe COPD as defined by mean FEV1 < 35% predicted. At baseline the LTOT group demonstrated significantly worse HRQL as defined by the Chronic Respiratory Questionnaire (CRQ) (fatigue, emotional function, mastery and total scores), total generic Dartmouth COOP Charts and anxiety domain of the Hospital Anxiety and Depression scale. Significant improvements in HRQL were noted at 2 and 6 months in the LTOT group. Conversely the non-LTOT group demonstrated a progressive decline in HRQL. Using validated criteria for a minimal clinically significant improvement in CRQ, there were 28 (67%) and 26 (68%) 'responders' at 2 and 6 months respectively in the LTOT group. The introduction of LTOT to patients with severe COPD fulfilling standard criteria was associated with early significant improvements in HRQL with sustained or further response at 6 months.

Short-burst oxygen immediately before and after exercise is ineffective in nonhypoxic COPD patients.

Short-burst oxygen therapy (SBOT) remains an unproven treatment for reduction of exertional dyspnoea in chronic obstructive pulmonary disease (COPD). This study aimed to assess whether SBOT before exercise reduces dyspnoea or improves performance, and whether SBOT after exercise reduces dyspnoea during recovery. Twenty-two clinically stable COPD patients (mean forced expiratory volume in one second 34% predicted, mean resting saturation 94%) attended a respiratory gymnasium and undertook four 6-min walk (6MW) tests at each of two sessions, 1 week apart. Cylinder air or oxygen was administered single-blind in random order for 5 min prior to the first two 6MW and during recovery following the final two 6MW. Dyspnoea was self-rated by subjects using the modified Borg scale. There was no significant difference in mean 6MW distance or final Borg score for air and oxygen given before exercise. There was also no significant difference in mean time-to-resting Borg score for air and oxygen given after exercise. Only two subjects demonstrated a clinically significant and consistent reduction in dyspnoea for oxygen compared with air either before or after exercise. Overall, short-burst oxygen therapy neither reduced dyspnoea nor improved performance. This study does not support the use of short-burst oxygen therapy either immediately before or after exercise.

Ambulatory oxygen improves quality of life of COPD patients: a randomised controlled study.

It is unknown whether acute response to ambulatory oxygen (O2) predicts longer term improvement in health-related quality of life (HRQL) in chronic obstructive pulmonary disease (COPD) patients. The aims of this study were 1) to assess the short-term clinical impact, as determined by HRQL, of ambulatory O2 in a 12-week, double-blind, randomised crossover study of O2 (versus cylinder compressed air) of dyspnoeic but not chronically hypoxic COPD patients with exertional desaturation < or = 88% (n=41), and 2) to determine whether either baseline characteristics or acute response to O2 predicts short-term (12 weeks) response. Primary outcome measures were Chronic Respiratory Questionnaire (CRQ), Hospital Anxiety and Depression scale and the short form (SF)-36. Improvements were seen in all domains of the CRQ for cylinder O2 compared with cylinder air. Significant improvements were also noted in anxiety and depression and in certain domains of the SF-36. There were 28 (68%) acute responders to cylinder O2 (defined as increase in 6-min walk > or = 54 m or decrease in post-Borg dyspnoea > or = 1) and 23 (56%) short-term responders (defined as clinically significant improvement in CRQ). However, acute and short-term responses were not correlated with no predictors of short-term response identified. At study completion, 14 (41%) of acute or short-term responders did not want to continue therapy, with 11 citing poor acceptability or tolerability. Short-term ambulatory oxygen is associated with significant improvements in health-related quality of life. These benefits cannot be predicted by baseline characteristics or acute response. Despite acute or short-term response, a substantial proportion of patients declined ambulatory oxygen.