***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: Reduced functional residual capacity ( FRC ) is consistently found in obese subjects . In 10 obese subjects ( mean + /- SE age 49.0 + /- 6 yr , weight 128.4 + /- 8 kg , body mass index 44 + /- 3 kg/m2 ) without respiratory disease , we examined 1 ) supine changes in total lung capacity ( TLC ) and subdivisions , 2 ) whether values of total respiratory resistance ( Rrs ) are appropriate for mid-tidal lung volume ( MTLV ) , and 3 ) estimated resistance of the nasopharyngeal airway ( Rnp ) in both sitting and supine postures . The results were compared with those of 13 control subjects with body mass indexes of < 27 kg/m2 .  Rrs at 6 Hz  was measured by applying forced oscillation at the mouth ( Rrs , mo ) or the nose ( Rrs , na ) ; Rnp was estimated from the difference between sequential measurements of Rrs , mo and Rrs , na . All measurements were made when subjects were seated and when supine . Obese subjects when seated had a restrictive defect with low TLC and FRC-to-TLC ratio ; when supine , TLC fell 80 ml and FRC fell only 70 ml compared with a mean supine fall of FRC of 730 ml in control subjects . Values of Rrs , mo and Rrs , na at resting MTLV in obese subjects were about twice those in control subjects in both postures . Relating total respiratory conductance ( 1/Rrs ) to MTLV , the increase in Rrs , mo in obese subjects was only partly explained by their reduced MTLV . Rnp was increased in some obese subjects in both postures . Despite the increased extrapulmonary mass load in obese subjects , further falls in TLC and FRC when supine were negligible . Rrs , mo at isovolume was increased . Further studies are needed to examine the causes of reduced TLC and increases in Rrs , mo and sometimes in Rnp in obese subjects We investigated exercise capacity after fluid depletion in patients with moderate congestive heart failure ( CHF ) . Twenty-one patients underwent ultrafiltration ( mean volume + /- SEM : 1,770 + /- 135 ml ) . Echocardiography , tests of pulmonary function , and a cardiopulmonary exercise test with hemodynamic and esophageal pressure monitoring were performed before ultrafiltration and 3 months later . Tests without invasive measurements were repeated 4 and 30 days after ultrafiltration . Twenty-one control patients followed the same protocol but did not have ultrafiltration . Patients who underwent ultrafiltration and increased their oxygen consumption at peak exercise ( peak VO2 ) by > 10 % at the 3-month evaluation ( group A1 , n = 9 ) were separated from those who did not ( group A2 , n = 8) ; 3 patients did not complete the follow-up . Four days after the procedure , peak VO2 had risen from 17.3 + /- 0.8 to 19.3 + /- 0.9 ml/min/kg in group A1 , and from 11.9 + /- 0.7 to 14.1 + /- 0.7 ml/min/kg in group A2 ( p < 0.01 ) . Plasma norepinephrine and pulmonary function were consistent with a greater severity of the syndrome in group A2 . At 3 months in group A1 , the relations of filling pressure to cardiac index of the right and left ventricles were shifted upward ; the esophageal pressure swing ( differences between end-expiratory and end-inspiratory pressure ) for a given tidal volume was lower ; the peak exercise dynamic lung compliance had increased from 0.10 + /- 0.05 to 0.14 + /- 0.03 L/mm Hg ( p < 0.01 ) . None of these changes were detected in group A2 and control patients . ( ABSTRACT TRUNCATED AT 250 WORDS Positioning combined with coughing and huffing is frequently used to promote secretion clearance . Maximum expiratory pressure ( MEP ) and peak expiratory flow rate ( PEFR ) have been used as surrogate measures of cough and huff strength . This study investigated the effect of body position on MEP and PEFR . Repeated measures of MEP and PEFR were performed across seven r and omised positions ( st and ing , chair sitting , sitting in bed with backrest vertical , sitting in bed with backrest at 45 degrees , supine , side lying , and side lying with head down tilt 20 degrees ) on 25 adults with normal respiratory function ( NRF ) and 11 adults with chronic airflow limitation ( CAL ) . For the NRF group , MEP in st and ing ( 143+/-10cmH2O , mean+/-SEM ) was significantly higher than MEP in chair sitting ( 133+/-10cmH2O ) which in turn was significantly higher than in the remaining positions . The MEP in head down tilt ( 108+/-9cmH2O ) was significantly lower than in all other positions . The PEFR in st and ing ( 571+/-24L/min ) was significantly higher and head down tilt ( 486+/-23L/min ) was significantly lower than in all other positions . For the CAL group , MEP in st and ing ( 134+/-18cmH2O ) was significantly higher , while in head down tilt ( 96+/-15cmH2O ) was significantly lower , than in most other positions . For the CAL group , PEFR in st and ing ( 284+/-40ml/sec ) was significantly higher , while in head down tilt ( 219+/-38ml/sec ) was significantly lower , than in most other positions . Body position has a significant effect on MEP and PEFR in NRF and CAL subjects , with the lowest values in the head down position . Thus , to maximise the strength of expiratory manoeuvres during treatments that use the head down position , patients should be encouraged to adopt a more upright position when coughing or huffing STUDY OBJECTIVE To define the effect of changes in body posture on flow-volume loops ( FVLs ) and four commonly used indices of upper airway obstruction ( UAO ) in young , nonobese normal subjects . DESIGN Prospect i ve comparative study . SETTING Pulmonary function laboratory at an academic hospital . PARTICIPANTS Thirty-one normal volunteers . INTERVENTION At least three FVLs per posture were obtained in the sitting , supine , and left and right lateral recumbent postures while maintaining a constant position of the head and neck in relation to the trunk . In each body posture , the largest observed flow rates were used to calculate the UAO indices . RESULTS When subjects changed from the sitting to each of the three recumbent postures , all spirometric values decreased significantly ( p<0.0001 ) . However , among the four UAO indices , only the FEV1/peak expiratory flow ratio increased significantly ( although only slightly , by 2.9 and 4.4 % , respectively ) in both the right and left lateral recumbent postures ( p<0.0001 ) , but not in the supine posture . None of the subjects developed an inspiratory or expiratory plateau on the FVL in any of the three recumbent postures . CONCLUSIONS In young , nonobese normal subjects , recumbency does not induce UAO , at least not detectable by changes in the FVL configuration or in UAO indices derived from the FVL . Furthermore , the study provides the upper limits of recumbency-related changes in the various UAO indices for young , nonobese normal subjects The effect of broxaterol , a new beta 2-agonist , on respiratory muscle endurance and strength was studied in a double-blind , placebo-controlled , r and omized crossover clinical trial in 16 patients with chronic obstructive pulmonary disease ( COPD ) with irreversible airway obstruction ( FEV1 = 57.1 percent of predicted ) . One patient withdrew from the study because of acute respiratory exacerbation . Inspiratory muscle strength was assessed by maximal inspiratory pressure ( MIP ) and endurance time was determined as the length of time a subject could breathe against inspiratory resistance ( target mouth pressure = 70 percent of MIP , Ti/Ttot = 0.4 ) . Broxaterol ( B ) or placebo ( P ) was given orally for seven days at the dose of 0.5 mg three times a day with a washout period of 72 h between study treatments . Measurements were performed before administration of B or P and 2 h ( six patients ) or 8 h ( nine patients ) after the end of each treatment . No significant changes in FEV1 or FRC were observed after B or P suggesting that diaphragmatic length was maintained constant with each treatment . The MIP did not significantly change , while endurance time increased after B in the patients tested at 2 h ( from 234.8 + /- 48.1 s to 284.0 + /- 48.0 s , p less than 0.05 ) and at 8 h ( from 187.2 + /- 31.1 s to 258.2 + /- 40.4 s , p less than 0.005 ) . No changes were observed after P. Minute ventilation , airway occlusion pressure ( P0.1 ) , integrated electromyographic activities of the diaphragm ( Edi ) , and intercostal parasternals ( Eic ) ( normalized to the value obtained during MIP ) showed no change during the endurance run with different treatments . We conclude that in a group of COPD patients with irreversible airway obstruction , B significantly improves respiratory muscle endurance , and that this does not arise as a result of an effect on neuromuscular drive or pulmonary mechanics , but may be mediated by peripheral factors OBJECTIVE To study the effect of posture on the hypercapnic ventilatory responses ( HCVR ) . DESIGN Nonr and omized controlled study . SETTING Rehabilitation hospital and a pulmonary institute . PARTICIPANTS Patients with neurologically stable C(5 - 8 ) tetraplegia ( n=12 ) and healthy control subjects ( n=7 ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES  Supine and seated forced vital capacity ( FVC ) and HCVR , and supine and erect blood pressure .  RESULTS FVC in the sitting position was reduced in patients with tetraplegia ( 52+/-13 % predicted ) ; supine FVC was 21 % higher ( P=.0005 ) . In the sitting position , HCVR was lower in patients than in controls ( 0.8+/-0.4 vs 2.46+/-0.3 L/min/mmHg , P<.001 ) . Supine HCVR was not significantly different between the groups . When HCVR was normalized to FVC , there was still a significant difference between patients and controls in the sitting position . Patients with tetraplegia were orthostatic ( mean supine blood pressure 91+/-13 mmHg vs mean erect blood pressure 61+/-13 mmHg , respectively , P<.0001 ) . The magnitude of the orthostatism correlated with that of the postural change in HCVR ( r=.93 , P<.0001 ) . CONCLUSIONS Respiratory muscle weakness may contribute to the attenuated HCVR in tetraplegia . However , the observation that supine HCVR is still low even when normalized to FVC suggests a central posture-dependent effect on the HCVR , which may be linked to the postural effect on arterial blood pressure [ Purpose ] The purpose of our study was to investigate the effect of different positions on pulmonary function test ( PFT ) values such as forced vital capacity ( FVC ) and forced expiratory volume in one second ( FEV1 ) of asthmatic patients .[Subjects and Methods ] Thirty subjects with severe asthma aged between 20–39 years were enrolled after they had signed a written consent . Subjects were selected using the inclusion criteria , and PFT were r and omly administered . Spirometer measurements ( FVC , FEV1 )  were taken in the supine , side lying on right , side lying on left , sitting and st and ing positions . Each measurement was taken three times , and the average values were analyzed . [ Results ] One- way analysis of variance ( ANOVA ) and Tukey ’s Test ( post hoc ) for pair- wise comparison indicated that there was a significant difference in the FEV1 values of the asthmatic patients however a significant difference was obtained between st and ing and supine positions . There was also a significant difference in the FVC values between the st and ing and supine lying position in the pair -wise comparison . [ Conclusion ] This study showed st and ing is the best position for measuring FEV1 and FVC of asthmatic subjects . The more upright the position , the higher the FEV1 and FVC will be Background —Pulmonary diffusing capacity for carbon monoxide ( Dlco ) , alveolar capillary membrane diffusing capacity ( Dm ) , and pulmonary capillary blood volume ( Vc ) are all significantly reduced after exercise . Objective —To investigate whether measurement position affects this impaired gas transfer . Methods —Before and one , two , and four hours after incremental cycle ergometer exercise to fatigue , single breath Dlco , Dm , and Vc measurements were obtained in 10 healthy men in a r and omly assigned supine and upright seated position . Results —After exercise , Dlco , Dm , and Vc were significantly depressed compared with baseline in both positions . The supine position produced significantly higher values over time for Dlco ( 5.22 ( 0.13 ) v 4.66 ( 0.15 ) ml/min/mm Hg/l , p = 0.022 ) and Dm ( 6.78 ( 0.19 ) v 6.03 ( 0.19 ) ml/min/mm Hg/l , p = 0.016 ) , but there was no significant position effect for V 
    Output:
    
In most studies involving healthy subjects or patients with lung , heart , neuromuscular disease , or obesity , FEV1 , FVC , FRC , PEmax , PImax , and /or PEF values were higher in more erect positions .
For subjects with tetraplegic SCI , FVC and FEV1 were higher in supine vs. sitting .
In healthy subjects , DLCO was higher in the supine vs. sitting , and in sitting vs. side-lying positions .
In patients with chronic heart failure , the effect of position on DLCO varied .