title: [Changes of work of breathing in patients with acute exacerbation of chronic obstructive pulmonary disease during non-invasive positive pressure ventilation].
abstract: OBJECTIVE
  To investigate the effect of non-invasive positive pressure ventilation (NIPPV) on the work of breathing (WOB) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  Eleven patients with acute exacerbation of COPD received pressure support ventilation (PSV) at different levels during NIPPV. The changes of inspiratory muscle effort and breathing pattern of the patients were observed.
  
  
  RESULTS
  The average minute ventilation (VE, P<0.01) and tidal volume (VT, P<0.05) of the patients were significantly higher during routine PSV and high pressure support (H-PS) than those during spontaneous breathing (SB), and the breathing pattern of the patients did not undergo significant changes during high positive end expiratory pressure (H-PEEP). The WOB of the inspiratory muscles was reduced significantly during PSV as compared with that measured in SB (P<0.01), while the WOB of exspiratory muscle increased significantly (P<0.01).
  
  
  CONCLUSIONS
  NIPPV can relieve the load of the inspiratory muscles in patients with acute exacerbation of COPD, and the WOB of the inspiratory muscles can be reduced by PSV, H-PEEP and H-PS (by 75%, 71% and 76%, respectively), but higher PSV during NIPPV can cause higher WOB of the exspiratory muscles.
authors: Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital of Guangzhou Medical College, Guangzhou 510120, China.
authors: Qun
authors: Q
authors: Luo
authors: Ying
authors: Y
authors: Li
authors: Rong-Chang
authors: RC
authors: Chen
authors: Yi-Min
authors: YM
authors: Li
mesh_terms: D000368:Aged; D045853:Exhalation / Q000502:physiology; D006801:Humans; D001239:Inhalation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011312:Pressure; D029424:Pulmonary Disease, Chronic Obstructive / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy*; D012123:Pulmonary Ventilation; D014939:Work of Breathing / Q000502:physiology*