title: Effects of an additional pressure support level on exercise duration in patients on prolonged mechanical ventilation.
abstract: OBJECTIVE
  Noninvasive positive pressure ventilation has been regarded as a strategy for improving exercise performance. Whether an increase in the ventilatory support level improves exercise performance in patients who have received invasive ventilation is unknown. The purpose of this study is to examine the effects of an additional level of pressure support (PS) ventilation on exercise tolerance in patients undergoing prolonged mechanical ventilation (PMV).
  
  
  METHODS
  This study examined 15 patients who were undergoing PMV. All patients performed an upper-arm exercise test at three PS levels: the baseline PS level (PS), a level 2 cmH2O higher than the baseline level (PS+2), and a level 4 cmH2O higher than the baseline level (PS+4). The physiological response, reasons for discontinuing the exercise test, and exercise duration were recorded and analyzed.
  
  
  RESULTS
  The tidal volume increased significantly from 271.7 ± 54.7 mL to 398.3 ± 88.7 mL at the PS+4 level (p = 0.01). Significant differences in exercise duration were observed at different PS levels. The exercise duration was significantly longer at the PS+4 level than at the PS and PS+2 levels (146.3 ± 139.9 seconds vs. 108.5 ± 85.9 seconds vs. 72.8 ± 43.9 seconds, p = 0.038) as their corresponding order. There were significant relationships between resting respiratory rate and exercise duration at the PS (r = -0.639, p = 0.034) and PS+2 levels (r = -0.668, p = 0.025).
  
  
  CONCLUSIONS
  In patients undergoing PMV, an additional PS level of up to 4 cmH2O compared with the baseline setting may help to improve exercise tolerance by prolonging exercise duration.
authors.affiliation: Department of Respiratory Care, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Physical Education, National Normal Taiwan University, Taipei, Taiwan.
authors.forename: Yen-Huey
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Department of Respiratory Care, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Lin
authors.affiliation: Department of Respiratory Care, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Division of Respiratory Therapy of Chang Gung Memorial Hospital, Linkou, Taiwan.
authors.forename: Hsiu-Feng
authors.initials: HF
authors.lastname: Hsiao
authors.affiliation: Department of Respiratory Care, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Division of Respiratory Therapy of Chang Gung Memorial Hospital, Linkou, Taiwan.
authors.forename: Ching-Tzu
authors.initials: CT
authors.lastname: Huang
authors.affiliation: Department of Respiratory Care, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Division of Respiratory Therapy of Chang Gung Memorial Hospital, Linkou, Taiwan; Division of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan.
authors.forename: Kuo-Chin
authors.initials: KC
authors.lastname: Kao
authors.affiliation: Department of Respiratory Care, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Division of Respiratory Therapy of Chang Gung Memorial Hospital, Linkou, Taiwan; Division of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan.
authors.forename: Li-Fu
authors.initials: LF
authors.lastname: Li
authors.affiliation: Department of Respiratory Care, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Division of Respiratory Therapy of Chang Gung Memorial Hospital, Linkou, Taiwan; Division of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan.
authors.forename: Chung-Chi
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Division of Pulmonary and Critical Care Medicine of Chang Gung Memorial Hospital, Chiayi, Taiwan. Electronic address: chestmed@adm.cgmh.org.tw.
authors.forename: Ying-Huang
authors.initials: YH
authors.lastname: Tsai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000534:rehabilitation* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods*; D012044:Regression Analysis; D013624:Taiwan
keywords: exercise tolerance; pressure support ventilation; prolonged mechanical ventilation; pulmonary rehabilitation