***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 
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    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 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 BACKGROUND : The development of portable liquid oxygen systems , capable of delivering high flow rate oxygen for long periods , justifies re assessment of the value of supplemental oxygen to aid exercise tolerance in patients with chronic respiratory insufficiency . The type of exercise test and the low oxygen flow rates previously used may account for the variable and often poor responses to supplemental oxygen reported in earlier studies . METHODS : The walking tolerance of 30 patients with severe respiratory disability was measured while they were breathing air and increasing doses of supplemental oxygen ( 2 , 4 , 6 1/min ) by using both the st and ard six minute walking test and an endurance walking test . To assess the initial learning effect and repeatability of the walking tests , three six minute walks and three endurance walks were performed on day 1 and a single walk of each type on days 2 , 3 , and 14 . In addition , oxygen dosing studies were performed on days 2 and 3 after the initial baseline walking tests . Each dosing study comprised four endurance walking tests or four six minute walking tests with patients breathing either air at a flow rate of 4 1/min from a portable cylinder or supplemental oxygen at a flow rate of 2 , 4 or 6 1/min from a portable liquid oxygen supply . The order of the tests was r and omised . Walking distance with each flow rate of oxygen was compared with walking distance with patients carrying cylinder air and for the initial unburdened walks . Breathlessness was assessed by visual analogue scoring on completion of each walk . RESULTS : Exercise ability and breathlessness were significantly improved with supplemental oxygen and this benefit outweighed the reduction in performance result ing from carrying the portable device . Supplemental oxygen at flow rates of 2 , 4 , and 6 1/min increased mean endurance walking distances by 37.9 % , 67.7 % and 85.0 % and six minute walking distances by 19.2 % , 34.5 % , and 36.3 % by comparison with distances when the patient was carrying air with a flow rate of 4 1/min . The additional work of carrying the portable gas supply reduced endurance walking distance by 22.2 % and six minute walking distance by 14.1 % by comparison with a baseline unburdened walk . Comparison of supplemental oxygen at 2 , 4 , and 6 1/min with the baseline unburdened performance showed increased endurance walking distances of 7.3 % , 30.4 % , and 43.9 % and six minute walking distances of 2.3 % , 15.5 % , and 17.0 % . Walking distance was increased by more than 50 % by comparison with an unburdened walk in seven patients with the endurance walking test but in only three patients with the six minute walking test . The benefit was similar in patients with obstructive and with interstitial lung disease . Individual responses were variable and only desaturation during the baseline walk in patients with obstructive lung disease had any predictive value for benefit with oxygen . CONCLUSION : As there was no clear relation between response to oxygen therapy and the patients ' characteristics , assessment for supplemental oxygen therapy will depend on exercise testing . It is suggested that portable oxygen should be considered only if a patient shows a 50 % improvement in exercise ability with high flow rate oxygen ( 4 - 6 1/min ) by comparison with an unburdened walk It is unclear whether short-term benefits from supplemental oxygen translate into improved quality of life in patients with severe COPD . In a 12 wk double-blind r and omized crossover study , we assessed the effects of supplemental air and oxygen on exercise performance ( step tests and 6 min walking distance [ 6MWD ] ) initially and after two 6 wk periods at home using exertional cylinder air or oxygen . We measured quality of life at baseline and after the two 6 wk domiciliary periods . The 26 patients ( 24 males ) had a mean age of 73 + /- 6 yr ; mean FEV1 , 0.9 + /- 0.4 L ; mean DLCO , 10.6 + /- 2.4 ml/min/mm Hg ; mean resting PO2 , 69 + /- 8.5 ( range 58 to 82 ) mm Hg ; mean PCO2 , 41 + /- 3.3 mm Hg ; and mean resting SaO2 , 94 + /- 2.1 ( mean + /- SD ) . Laboratory tests were performed breathing intranasal air or oxygen at 4 L/min , and measurements were made of SaO2 and Borg dysnea scores .  Supplemental oxygen increased 6MWD and steps by small , statistically significant increments acutely at baseline and after 6 and 12 wk , without corresponding falls in Borg score . Degree of desaturation at baseline did not correlate with increase in 6MWD or steps achieved at baseline or at 6 or 12 wk , nor with the domiciliary gas used . There was no difference in 6MWD or steps achieved while breathing supplemental oxygen after 6 wk of domiciliary oxygen compared with domiciliary air . Small improvements in quality of life indices were found after domiciliary oxygen , and mastery also improved after domiciliary air . There were no differences in quality of life , however , when domiciliary oxygen was compared with domiciliary air . Although oxygen supplementation induced small acute increments in laboratory exercise performance , such improvements had little impact on the patients ' daily lives Background : The effects of oxygen on recovery from exercise in patients with chronic obstructive pulmonary disease ( COPD ) are not clearly known . A study was undertaken to determine whether oxygen given after maximal exercise reduced the degree of dynamic hyperinflation and so reduced the perception of breathlessness . Methods : Eighteen patients with moderate to severe COPD performed  maximal symptom limited exercise on a cycle ergometer . During recovery they received either air or oxygen at identical flow rates in a r and omised , single blind , crossover design . Inspiratory capacity , breathing pattern data , dyspnoea intensity , and leg fatigue scores were collected at regular intervals during recovery . At a subsequent visit patients underwent a similar protocol but with a face mask in situ to eliminate the effects of instrumentation . Results : When oxygen was given the time taken for resolution of dynamic hyperinflation was significantly shorter ( mean difference between air and oxygen 6.61(1.65 ) minutes ( 95 % CI 3.13 to 10.09 ) , p = 0.001 ) . Oxygen did not , however , reduce the perception of breathlessness during recovery nor did it affect the time taken to return to baseline dyspnoea scores in either the instrumented or non-instrumented state ( mean difference 2.11 ( 1.41 ) minutes ( 95 % CI −0.88 to 5.10 ) , p = 0.15 ) . Conclusions : Oxygen reduces the degree of dynamic hyperinflation during recovery from exercise but does not make patients feel less breathless than breathing air . This suggests that factors other than lung mechanics may be important during recovery from exercise , or it may reflect the cooling effect of both air and oxygen Background : Evidence for improved exercise tolerance or relief of breathlessness by short term use of oxygen before or after exercise in patients with chronic obstructive pulmonary disease ( COPD ) is scant , and guidelines for this treatment are lacking despite widespread provision in the UK . Methods : The effect of oxygenation either before or after exercise on perception of breathlessness and walk distance was studied in a group of patients with moderate to severe COPD ( mean forced expiratory volume in 1 second ( FEV1 ) 34 % of predicted , mean 6 minute walk distance on air 283 m ) , all of whom desaturated by at least 4 % on submaximal exercise . Oxygen ( 28 % ) or air was delivered double blind and in r and om order , either for 5 minutes before a st and ard 6 minute walk test ( n=34 ) or for 5 minutes following the end of the test ( n=18 ) . Exercise tolerance was measured as the distance achieved and breathlessness was assessed using visual analogue scales ( VAS ) which were scored before and after exercise and during recovery . Results : No increase in mean walk distance after oxygen ( 288 v 283 m ) and no improvement in mean breathlessness scores ( 58 v 54 mm ) or recovery times occurred with oxygen taken either before ( 177 v 184 seconds ) or after exercise ( 182 v 151 seconds ) . Conclusions : This group of patients with COPD derived no physiological or symptomatic benefit from oxygen breathed for short periods before or after submaximal exercise . Domiciliary oxygen should only be prescribed for such patients if they have shown objective evidence of benefit on exercise testing BACKGROUND In two of three phase 3 trials , pirfenidone , an oral antifibrotic therapy , reduced disease progression , as measured by the decline in forced vital capacity ( FVC ) or vital capacity , in patients with idiopathic pulmonary fibrosis ; in the third trial , this end point was not achieved . We sought to confirm the beneficial effect of pirfenidone on disease progression in such patients . METHODS In this phase 3 study , we r and omly assigned 555 patients with idiopathic pulmonary fibrosis to receive either oral pirfenidone ( 2403 mg per day ) or placebo for 52 weeks . The primary end point was the change in FVC or death at week 52 . Secondary end points were the 6-minute walk distance , progression-free survival , dyspnea , and death from any cause or from idiopathic pulmonary fibrosis . RESULTS In the pirfenidone group , as compared with the placebo group , there was a relative reduction of 47.9 % in the proportion of patients who had an absolute decline of 10 percentage points or more in the percentage of the predicted FVC or who died ; there was also a relative increase of 132.5 % in the proportion of patients with no decline in FVC ( P<0.001 ) . Pirfenidone reduced the decline in the 6-minute walk distance ( P=0.04 ) and improved progression-free survival ( P<0.001 ) . There was no significant between-group difference in dyspnea scores ( P=0.16 ) or in rates of death from any cause ( P=0.10 ) or from idiopath 
    Output:
    
This review found no evidence to support or refute the use of ambulatory or short burst oxygen in ILD due to the limited number of included studies and data .