Efficacy and Physiology of Nasal High Flow Therapy

Efficacy and Physiology of Nasal High Flow Therapy (AIRVO2™, Fisher&Paykel) in Patients With Chronic Obstructive Pulmonary Disease (COPD) and Chronic Hypercapnic Respiratory Failure

The effects of a nasal high-flow (NHF) therapy in patients with chronic obstructive hypercapnic respiratory failure are still not sufficiently known yet. The aim of this study is a step-by-step generation of physiological data about gas exchange and respiration under high flow therapy using a nasal cannula with an AIRVO 2 device to provide NHF, leading to an analysis of the effects of high flow on PCO2 levels, exercise capacity, quality of life and gas exchange in a long term home treatment compared to a standard low flow long term oxygen therapy (LOT). Hypothesis: NHF and LOT therapy show differences in measured mean overnight transcutaneous carbon dioxide partial pressure (PCO2) after four weeks of treatment.

Stage 1: Respiratory Physiology. Aim of this Stage is to investigate the effects of nasal High Flow (NHF) therapy in patients in progressed stages of COPD, by measuring physiologic parameters like tidal volume, breathing frequency and expiratory PCO2 concentration. Stage 2: Efficacy of short term NHF. Aim of this Stage is to evaluate the efficacy of two flow rates (20 L/min and 35 L/min) regarding alveolar ventilation in overnight therapy. For this reason, patients will have two PSG sleep studies during their hospital stay, under 20 L/min and 35 L/min NHF therapy in randomized order. Stage 3: Home Care monitoring. Aim of this Stage is to compare long term influences of NHF and LOT on PCO2 levels randomised crossover, 4 weeks each treatment. Stage 4: Long Term Home Care monitoring . Aim of this stage is the long term follow up (12 month) of patients to examine the compliance of a sufficient NHF therapy. Patients will retain the NHF therapy if they are responders (PCO2 improvement in stage 3 of at least 2 mmHG with NHF versus LOT) and willing and able to use NHF and a patient log. All patients will be monitored for the next 12 month. After 6 month there will be a control phone call.

overnight nasal High Flow (NHF) therapy+ individually titrated supplemental oxygen (2-6 L/min),total 35 L/min, 4 weeks at home

AIRVO 2 device therapy is either a humidifier with integrated flow generator that delivers warmed and humidified respiratory gases to spontaneously breathing patients through a variety of patient interfaces. Flow rates up to 60 L/min are available to the user, depending on the patient interface and mode of operation.In this study, flow rates of 20 L/min and 35 L/min will be compared.

Oxygen will individually be added to NHF in order to achieve stable oxygen saturation by pulse oximetry (SpO2) values of 88% to 92%.

In two baseline measurements the aim is to evaluate the efficacy of two flow rates (20 L/min and 35 L/min) regarding alveolar ventilation in overnight therapy. For this reason, patients will have two polysomnographic sleep studies (PSG) during their hospital stay, under 20 L/min and 35 L/min NHF therapy in randomized order. Primary objective is the mean overnight transcutaneous PCO2 value, absolute as well as time spent >50 mmHg.

In home care monitoring is the aim to compare long term influences of NHF and LOT on PCO2 levels. Primary objective is the mean overnight transcutaneous PCO2 level measured after 4 weeks of each treatment phase.

All patients will be monitored under NHF or another sufficient therapy for the next 12 month followed by another mean overnight transcutaneous PCO2 level measure.

SGRQ is a disease-specific instrument designed to measure impact on overall health, daily life, and perceived well-being in patients with obstructive airways disease.

sleep quality, measured by sleep efficiency, e.g. total sleep time vs sleep period time from PSG report.

Inclusion Criteria: Age 40-80 Male and female COPD patients with chronic respiratory insufficiency (pH >7.35 and PCO2 > 50mmHg) Stable respiratory situation Exclusion Criteria: Decompensated heart, liver or kidney failure. Pregnancy or nursing period Participation in another clinical trial within the last 4 weeks Drug abuse Incapable of giving consent Known obstructive sleep apnea syndrome (OSA) (AHI>10) noninvasive ventilation (NIV) therapy