As outlined in this Figure, the Barnes Healthcare Study^[1] was performed to evaluate the impact of a home NIV program for severe COPD patients.  The goal was to support COPD patients at home in order to reduce emergency admissions for acute exacerbations and overall healthcare utilization.  Figure 3 shows the study eligibility criteria.

• The patients all had COPD GOLD Stage 3/4, were persistently hypercapnic, had OSA [obstructive sleep apnea] ruled out, and importantly, all of these patients had at least two COPD-related hospital emergency admissions within the prior year and had demonstrated a willingness to use and adhere to NIV treatment.
• The study design was a multicenter retrospective single-arm nonrandomized study.  A total of 398 patients were included upon meeting eligibility criteria.
• Patients received home-based noninvasive positive pressure ventilation with the ability to deliver ventilation based on patient-determined need.  Specifically, the patients received a Trilogy 100 (Philips Respironics) device set at an EPAP range of 5–15 cm H₂O, PS_min – PS_max range 2–26 cm H₂O, with an automatic backup rate, and AVAPS-AE set to 5–7 mL/kg ideal body weight (IBW), according to patient tolerance.
• The primary outcome measured was readmission to the hospital at 1 and 2 years post initiation, and secondary outcomes included time to death and a calculated mortality rate.