Non-invasive positive pressure ventilation for severe stable chronic obstructive pulmonary disease
Kohnlein 2014 trial design and results
Design
Randomised controlled trial across 36 respiratory units in Germany and Austria
Treatment
Long-term non-invasive positive pressure ventilation targeted to reduce PaCO2 by at least 20% or below 48.1 mmHg, plus standard treatment
Control
Standard treatment alone
Population
195 patients with severe stable hypercapnic COPD: 102 ventilation and 93 control
Follow-up
1 year
Primary endpoint
One-year all-cause mortality
Result
One-year mortality was 12% (12 of 102) in the ventilation group and 33% (31 of 93) in the control group — hazard ratio 0.24 (95% CI 0.11 to 0.49, p=0.0004). Fourteen patients (14%) reported facial skin rash from the mask.
Secondary endpoints
Blood gases, lung function, quality of life, adverse effects
The addition of long-term NPPV to standard treatment improves survival of patients with hypercapnic, stable COPD when NPPV is targeted to greatly reduce hypercapnia.
The trial authors, in the published abstract
How it has aged
The conditional clause in the authors' conclusion is the finding: benefit appeared only because ventilation was titrated aggressively to actually reduce hypercapnia. Earlier trials used low pressures, achieved no CO2 change, and found nothing. A hazard ratio of 0.24 is exceptional, and the trial is small enough that the confidence interval is wide. See also HOT-HMV.
Publications
Non-invasive positive pressure ventilation for the treatment of severe stable chronic obstructive pulmonary disease: a prospective, multicentre, randomised, controlled clinical trial
Köhnlein T, Windisch W, Köhler D, et al. Non-invasive positive pressure ventilation for the treatment of severe stable chronic obstructive pulmonary disease: a prospective, multicentre, randomised, controlled clinical trial. Lancet Respir Med 2014 Sep;2(9):698-705.
One-year mortality 12% versus 33%
Benefit conditional on titrating ventilation to reduce hypercapnia substantially