***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: We examined whether arterial hypoxemia impairs incremental exercise performance in subjects with interstitial lung disease ( ILD ) . Seven subjects underwent two incremental exercise tests on a bicycle ergometer in r and om order ; one while breathing room air ( RA ) , and the other while breathing 60 % O2 .  Maximal exercise performance was impaired in all subjects : maximal oxygen uptake ( peak VO2 ) was 56 + /- 4 % predicted ( + /- SEM ) ; and all subjects demonstrated significant arterial oxygen desaturation during exercise breathing RA ( mean 11 + /- 1 % ) . Breathing 60 % O2 during exercise result ed in a significant increase in peak VO2 ( RA : 1.32 + /- 0.05 L/min ; O2 : 1.58 + /- 0.08 L/min ; p < 0.05 ) , exercise duration ( RA : 390 + /- 21 s ; O2 : 458 + /- 24 s ; p < 0.01 ) and maximal work load ( RA : 112 + /- 6 watts ; O2 : 129 + /- 6 watts ; p < 0.005 ) . There was no significant difference in maximal minute ventilation ( VI ) achieved at the end of both tests . At matched ventilation ( 90 % peak VI from the RA test ) , respiratory frequency ( f ) was significantly higher ( RA : 33 + /- 2 breaths/min ; O2 : 35 + /- 2 breaths/min ; p < 0.05 ) , and tidal volume ( VT ) significantly lower ( RA : 1.72 + /- 0.15 L ; O2 : 1.64 + /- 0.12 ; p < 0.05 ) when subjects exercised breathing oxygen . We conclude that arterial hypoxemia significantly impairs incremental exercise performance in subjects with ILD , but that mechanisms other than arterial oxygen desaturation are responsible for the rapid , shallow breathing pattern these subjects adopt during exercise CONTEXT Clinical ly important differences in chronic refractory breathlessness are ill defined but important in clinical practice and trial design . OBJECTIVES To estimate the clinical relevance of differences in breathlessness intensity using distribution and patient anchor methods . METHODS This was a retrospective data analysis from 213 data sets from four clinical trials for refractory breathlessness .  Linear regression was used to explore the relationship between study effect size and change in breathlessness score ( 0 - 100 mm visual analogue scale ) and to estimate the change in score equivalent to small , moderate , and large effect sizes . Pooled individual blinded patient preference data from three r and omized controlled trials were analyzed . The difference between the mean change in Day 4 minus baseline scores between preferred and non-preferred arms was calculated . RESULTS There was a strong relationship between change in score and effect size ( P = 0.001 ; R(2 ) = 0.98 ) . Values for small , moderate , and large effects were -5.5 , -11.3 , and -18.2 mm . The participant preference change in score was -9 mm ( 95 % CI , -15.8 , -2.1 ) ( P = 0.008 ) . CONCLUSION This larger data set supports a clinical ly important difference of 10 mm . Studies should be powered to detect this difference INTRODUCTION Idiopathic pulmonary fibrosis ( IPF ) is a severe disease with no known effective therapy . Patients with IPF may develop severe increase of pulmonary arterial pressure ( PAP ) on exercise , the mechanisms of which is not clearly identified . OBJECTIVES To determine whether oxygen may correct the increase of PAP developed during exercise in patients with IPF . PATIENTS AND METHODS We performed a prospect i ve study on patients with IPF and no hypoxaemia at rest . The absence of pulmonary hypertension ( PH ) at rest was confirmed by echocardiography ( systolic PAP < 35 mmHg ) . Eight patients underwent  echocardiography during exercise in air and with oxygen ( to maintain saturation of at least 94 % ) . Right ventricle-right atrium gradient and cardiac output were measured at rest , after each increment and at peak . We then compared the echocardiographic results obtained for air and oxygen . RESULTS All patients developed significant increase of SPAP on exercise ( 73 + /- 14 mmHg in air ) . Oxygen did not significantly improve SPAP on exercise ( SPAP : 76 + /- 15 mmHg ) . Echocardiographic characteristics were similar between air and oxygen except for exercise tolerance in term of workload ( p=0.045 ) and endurance ( p=0.017 ) . Resting pulmonary function tests did not predict the occurrence of increase of PAP on exercise . CONCLUSION Our results demonstrate that oxygen does not improve exercise-induced increase of PAP in patients with IPF and support the hypothesis that hypoxic vaso-constriction is not the main mechanism of acute increase of PAP during exercise A controlled trial of long term domiciliary oxygen therapy has been carried out in three centres in the U.K. The 87 patients , all under 70 years of age , who took part had chronic bronchitis or emphysema with irreversible airways obstruction , severe arterial hypoxaemia , carbon dioxide retention , and a history of congestive heart failure . The patients were r and omised to oxygen therapy ( treated ) or no oxygen ( controls ) . Oxygen was given by nasal prongs for at least 15 h daily , usually at 2 1/min . The two groups were well matched , both clinical ly and in terms of lung function and other laboratory findings . 19 of the 42 oxygen  treated patients died in the five years of survival follow-up compared with 30 out of 45 controls : in the 66 men in this trial the survival advantage of oxygen did not emerge until 500 days had elapsed . Survival for the 12 female controls was surprisingly poor , 8 of them being dead at 3 years . Mortality was not easy to predict , though a summation of arterial carbon dioxide tension and red cell mass was helpful . Neither time spent in hospital because of exacerbations of respiratory failure nor work attendance were affected by oxygen therapy , but these patients were very ill at the start of the trial and many had already retired on grounds of age or ill-health . Physiological measurements suggested that oxygen did not slow the progress of respiratory failure in those who died early . However , in longer term survivors on oxygen , arterial oxygenation did seem to stop deterioration At six centers , 203 patients with hypoxemic chronic obstructive lung disease were r and omly allocated to either continuous oxygen ( O2 ) therapy or 12-hour nocturnal O2 therapy and followed for at least 12 months ( mean , 19.3 months ) . The two groups were initially well matched in terms of physiological and neuropsychological function . Compliance with each oxygen regimen was good . Overall mortality in the nocturnal O2 therapy group was 1.94 times that in the continuous O2 therapy group ( P = 0.01 ) . This trend was striking in patients with carbon dioxide retention and also present in patients with relatively poor  lung function  , low  mean nocturnal oxygen saturation , more severe brain dysfunction , and prominent mood disturbances . Continuous O2 therapy also appeared to benefit patients with low mean pulmonary artery pressure and pulmonary vascular resistance and those with relatively well-preserved exercise capacity . We conclude that in hypoxemic chronic obstructive lung disease , continuous O2 therapy is associated with a lower mortality than is nocturnal O2 therapy . The reason for this difference is not clear We have compared the symptomatic benefit of air and oxygen at rest in hypoxemic patients with chronic obstructive airway disease ( COAD ) or interstitial lung disease ( ILD ) . A total of 12 severely disabled patients with COAD ( mean + /- SEM , PaO2 , 50.3 + /- 3.7 mm Hg ) and 10 with ILD ( PaO2 , 48.0 + /- 3.1 mm Hg ) received 28 % oxygen and air by Venturi face mask , each gas on two occasions , in a double-blind r and omized fashion . SaO2 increased ( p less than 0.01 ) in both groups during oxygen breathing : COAD , 85.1 + /- 2.3 % versus 93.1 + /- 1.4 % ; ILD , 85.5 + /- 1.7 % versus 94.7 + /- 0.9 % . The patients with COAD stated that air helped their breathing on 15 of 24 occasions and that oxygen helped on 22 of 24 occasions ( p less than 0.05 ) . In the patients with ILD the values were 6 of 20 and 13 of 20 occasions , respectively ( p less than 0.05 ) . In both groups of patients the severity of breathlessness recorded on a 100-mm visual analog scale was significantly ( p less than 0.05 ) lower during oxygen breathing : COAD , 29.6 + /- 4.5 versus 45.6 + /- 6.0 ; ILD , 30.2 + /- 5.1 versus 48.1 + /- 4.4 . Ventilation measured by magnetometers was significantly lower during oxygen breathing in the patients with COAD ( 8.2 + /- 1.0 versus 9.3 + /- 1.1 L/min ; p less than 0.05 ) , but the difference between oxygen and air in patients with ILD was not statistically significant ( 9.3 + /- 1.3 versus 11.2 + /- 1.6 L/min ; p greater than 0.05 ) . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND AND OBJECTIVE The effects of ambulatory oxygen for idiopathic pulmonary fibrosis ( IPF ) patients without resting hypoxemia have not been eluci date d. The purpose of this study was to assess the effect of ambulatory oxygen on dyspnea in IPF patients without resting hypoxemia but with desaturation on exertion . METHODS This was a double-blind , placebo-controlled , r and omized crossover trial of ambulatory oxygen versus ambulatory air .  Patients with IPF who had a partial pressure of arterial oxygen ( PaO2 ) between 60 mm Hg and 80 mm Hg at rest , and desaturation of 88 % or less in a room-air 6-min walk test were eligible . Patients underwent a st and ardized 6-min walk test and a 6-min free walk test under each ambulatory gas . Oxygen and air were provided at 4 L/min intranasally . Dyspnea was evaluated immediately , 1 , and 2 min after the tests . RESULTS Twenty patients ( 16 men ) , with a mean age of 73.5 ( SD 4.1 ) years , % predicted forced vital capacity ( FVC ) of 71.0 ( 13.3 ) % , % predicted diffusion capacity for carbon monoxide ( DLco ) of 57.0 ( 13.3 ) % , and PaO2 of 72.5 ( 5.4 ) mm Hg were recruited . No significant differences in dyspnea were observed between ambulatory oxygen and air at each time point . However , some patients showed improvement in dyspnea with oxygen on an individual basis . CONCLUSIONS Since oxygen provides no additional benefit over air in terms of exertional dyspnea for IPF patients without resting hypoxemia , routine prescription of ambulatory oxygen is not recommended . However , assessment on an individual basis is necessary . Trial registration . UMIN Clinical Trial Registry ; No.:UMIN000005098 ; URL : 
    Output:
    
This systematic review showed no effects of oxygen therapy on dyspnoea during exercise in ILD , although exercise capacity was increased .