RESUMO
INTRODUCTION: There are many mechanisms for improving the clinical and blood gas status of patients with the obesity hypoventilation syndrome (OHS) or chronic obstructive pulmonary disease (COPD) by non-invasive ventilation (NIV) at home. Our objective was to set up a pilot study to evaluate the potential modification of the sensitivity of the respiratory centers to CO2 by NIV in paired new COPD and OHS patients. METHODS: We assessed the sensitivity of the respiratory centers to CO2 by the Read method in 3 COPD patients and 3 OHS patients newly treated by NIV and again 3 months later. We compared their results to those of 6 control subjects. RESULTS: All the patients included had altered ventilatory responses to CO2 with slopes of less of than 1 L.min-1.mmHg-1. Mean coefficients of variation were significantly higher in patients than in healthy subjects (P=0.007). Patients who improved their CO2 sensitivity slope were those most observant of NIV. CONCLUSION: This work showed significant changes in the ventilatory response to hypercapnia in patients with either OHS or COPD after NIV therapy. The significance of these changes deserves to be studied.