title: Efficacy of nocturnal nasal ventilation in stable, severe chronic obstructive pulmonary disease during a 3-month controlled trial.
abstract: OBJECTIVE
  To evaluate the efficacy of nocturnal nasal ventilation (NNV) in patients with rigidly defined, severe but stable chronic obstructive pulmonary disease (COPD) and hypercapnia.
  
  
  METHODS
  By randomization, eligible patients were assigned to an active or a sham treatment arm. Data from these two groups were analyzed statistically.
  
  
  METHODS
  Initially, 35 patients with severe COPD (forced expiratory volume in 1 second [FEV1] of less than 40% predicted) and daytime hypercapnia (arterial carbon dioxide tension [PaCO2] of more than 45 mm Hg) were enrolled in a 3-month NNV trial. After a minimal observation period of 6 weeks, 13 patients were judged to be clinically stable and were randomized to NNV (N = 7) or sham (N = 6) treatment, consisting of nightly use of a bilevel positive airway pressure (PAP) device set to deliver an inspiratory pressure of either 10 or 0 cm of water (H2O). The device was used in the spontaneous or timed mode and set to a minimal expiratory pressure of 2 cm H2O. Patients underwent extensive physiologic testing including polysomnography and were introduced to the bilevel PAP system during a 2.5-day hospital stay.
  
  
  RESULTS
  The NNV and sham treatment groups were similar in mean age (71.0 versus 66.5 years), PaCO2 (54.7 versus 48.5 mm Hg), and FEV1 (0.62 versus 0.72 L). Only four of seven patients in the NNV group were still using the bilevel PAP device at the completion of the trial, as opposed to all six patients in the sham group. Only one patient had a substantial reduction in PaCO2 - from 50 mm Hg at baseline to 43 mm Hg after 3 months of NNV. He declined further NNV treatment with bilevel PAP. Sham treatment did not lower PaCO2. Lung function, nocturnal oxygen saturation, and sleep efficiency remained unchanged in both groups.
  
  
  CONCLUSIONS
  Disabled but clinically stable patients with COPD and hypercapnia do not readily accept and are unlikely to benefit from NNV.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Mayo Clinic Rochester, Minnesota 55905, USA.
authors.forename: P C
authors.initials: PC
authors.lastname: Gay
authors.forename: R D
authors.initials: RD
authors.lastname: Hubmayr
authors.forename: R W
authors.initials: RW
authors.lastname: Stroetz
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000628:therapy*; D008173:Lung Diseases, Obstructive / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D011175:Positive-Pressure Respiration; D012129:Respiratory Function Tests; D012890:Sleep; D013147:Spirometry; D013997:Time Factors