The investigators carried out research with patients using CPAP. Due to air trapping and auto-PEEP, which increase breathing effort in patients with COPD and obesity-hypoventilation syndrome (OHS), the ventilatory mechanics of these patients have been altered. P0.1 measures the ventilatory drive and, in turn, the respiratory effort. The aim of the study was to assess P0.1 changes in persons with COPD or OHS who were undergoing positive pressure therapy after treatment. Positive airway pressure was used as part of the treatment for people with COPD and OHS in a prospective study. P0.1 was identified at study inclusion and 6 months throughout the course of treatment. The research included a total of 88 subjects, among which 56% were males under the age group of 65 ± 9 y old. Among them, 54 (61%) had OHS, and 34 (39%) had COPD. About 50 (56%) had air trapping, with an initial P0.1 value of 3.0 ± 1.3 cm H2O compared with 2.1 ± 0.7 cm H2O for patients who did not suffer from air trapping (P=.001). After 6 months of therapy, patients with air trapping had P0.1 values of 2.3 ± 1.1 and 2.1 ± 1 cm H2O, respectively (P=.53), which were equivalent to subjects without it. In individuals with COPD, the initial P0.1 was 2.9±1.4 cm H2O, and after 6 months, it was 2.2 ± 1.1 cm H2O (P=.02) At baseline and 6 months later, initial P0.1 in OHS patients was 2.4±1.1 cm H2O and 2.2±1.0 cm H2O (P=.28), respectively The conclusion drawn by the researchers showed that patients with greater P equals 0.1 as a metric of respiratory effort were linked to COPD and air trapping. After therapy, a decline in P0.1 suggests less respiratory effort.