title: Outcome of patients with stable COPD receiving controlled noninvasive positive pressure ventilation aimed at a maximal reduction of Pa(CO2).
abstract: OBJECTIVE
  The role of noninvasive positive pressure ventilation (NPPV) has been well established in the treatment of acute hypercapnic respiratory failure due to COPD. However, evidence for a sustained improvement in blood gas levels and survival in patients with stable hypercapnic COPD following NPPV is still lacking. There is concern that this might be due to low inspiratory pressures of < 18 cm H2O used in previous studies, which thereby did not achieve a reduction of Pa(CO2). Therefore, the 2-year survival and changes in lung function and blood gas levels were analyzed in patients with stable hypercapnic COPD in whom controlled pressure-limited NPPV was titrated to achieve a maximal improvement in Pa(CO2).
  
  
  METHODS
  Retrospective study between March 1997 and September 2003.
  
  
  METHODS
  General ward of a university hospital.
  
  
  METHODS
  Thirty-four consecutive patients with stable (mean pH 7.40 +/- 0.03) hypercapnic COPD (mean age, 63.4 +/- 9.7 years [+/- SD]; mean body mass index, 28.3 +/- 7.3 kg/m2).
  
  
  RESULTS
  Daytime Pa(CO2) during spontaneous breathing decreased by 6.9 +/- 8.0 (95% confidence interval, - 9.9 to - 3.9), from 53.3 +/- 4.8 to 46.4 +/- 7.0 mm Hg (p < 0.001); while daytime Pa(O2) increased by 5.8 +/- 9.4 (95% confidence interval, 2.3 to 9.3), from 51.7 +/- 8.8 to 57.5 +/- 9.3 mm Hg (p = 0.002); and FEV1 increased by 0.14 +/- 0.16 (95% confidence interval, 0.08 to 0.20), from 1.03 +/- 0.54 to 1.17 +/- 0.59 L (p < 0.001) after 2 months of NPPV. This was achieved with mean inspiratory pressures of 27.7 +/- 5.9 cm H2O (range, 17 to 40 cm H2O) at a mean respiratory rate of 20.8 +/- 2.5 breaths/min (range, 14 to 24 breaths/min). The 2-year survival rate was 86%.
  
  
  CONCLUSIONS
  Controlled NPPV using a mean inspiratory pressure of 28 cm H2O is well tolerated over longer periods and can improve blood gas levels and lung function. Prospective, randomized controlled trials of high-intensity NPPV are required to evaluate its role in patients with stable hypercapnic COPD.
authors.affiliation: Department of Pneumology, University Hospital Freiburg, Killianstrasse 5, D - 79106 Freiburg, Germany. windisch@med1.ukl.uni-freiburg.de
authors.forename: Wolfram
authors.initials: W
authors.lastname: Windisch
authors.forename: Sergej
authors.initials: S
authors.lastname: Kostić
authors.forename: Michael
authors.initials: M
authors.lastname: Dreher
authors.forename: Johann Christian
authors.initials: JC
authors.lastname: Virchow
authors.forename: Stephan
authors.initials: S
authors.lastname: Sorichter
mesh_terms: D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood* / Q000378:metabolism; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000097:blood / Q000209:etiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000150:complications / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide