The purpose of this trial ist to investigate the difference of the efficacy of two systems for breath support in patients with COPD.

The trial consists of 12 weeks of therapy that is divided into two sections. In the first 6-week section patients receive treatment with either TNI or BiPAP and in the second 6-week section treatment is changed. The starting therapy is allocated to the patients via randomisation and should be started directly after the baseline visit.

The treatment and the follow-up period end with the second visit after the second treatment section and the patient decides which device he/she wants to use further.

Inclusion Criteria:

• presence of COPD with chronic respiratory global insufficiency
• chronic day-hypercapnia with pCO2 >= 50 mmHg and typical symptoms of ventilatory insufficiency OR patients with exacerbation (after abate of acute symptomatology) with documented hypercapnia >= 50 mmHG on preliminary findings
• age 18 or older
• the patient or caretaker must be able to operate the device after a specific training
• patient must be willing to use the nHF-/BiPAP-device for the whole trial period for at least 5 hours/day
• patient must be able to answer the questionnaires
• written informed consent is obtained

Exclusion Criteria:

• presence of acute respiratory insufficiency
• exacerbation of type I or II in the last 4 weeks
• conservative therapy including long-term oxygen therapy according to GOLD update 2011 is not exhausted
• previous treatment with NIV (non-invasive ventilation) in the last 14 days
• clinical instability or acute illness (e.g. acute myocardial infarction, tachycardial atrial fibrillation)
• signs of cardial decompensation (e.g. edema in the lower limbs, pleural effusion)
• other serious concomitant diseases, the assessment of eligibility is at the discretion of the investigator
• contraindications for NIV
• anamnestic suspicion or proven obstructive sleep apnea (OSA)
• relevant systemic infections, assessment of eligibility is at the discretion of the investigator
• BMI > 30
• other additional pulmonary diseases of other genesis or diseases that affect breathing (e.g. mucoviscidosis, scoliosis, muscular diseases)
• lack of compliance
• participation in other interventional trials at the same time
• pregnant or nursing women
• fertile female patients without effective contraceptive measures during trial participation