Effects of Supplemental Oxygen Delivery Via Demand Versus Continuous Flow in Hypoxemic COPD Patients
Effects of Supplemental Oxygen Delivery Via Demand Versus Continuous Flow in Hypoxemic COPD Patients
Oxygen supplementation has been proven to be effective in hypoxemic COPD patients by
 increasing oxygenation and reducing dyspnea. In clinical practice there are three common
 oxygen delivery systems used: continuous oxygen flow (CF), demand oxygen delivery with liquid
 oxygen (DDL) and demand oxgen delivery with portable oxygen concentrator (DDC). The CF
 involves considerable wastage of oxygen because oxygen is supplied during in- and exhalation.
 Demand oxygen delivery saves oxygen and results in a comparable oxygen saturation at rest in
 COPD patients. However, it is unknown, if oxygen supplementation via demand oxygen delivery
 is also sufficient during exercise in hypoxemic COPD patients. In addition, it has to be
 considered that the lower weight of demand oxygen delivery system might enable patients for
 higher physical activity level and mobility in daily life.

 The effects of These three oxygen delivery systems shall be investigated by a randomized,
 controlled cross-over Trial. Every patient has to perform an Incremental Shuttle Walk Test
 and three Endurance Shuttle Walk Tests with three different oxygen supplementation (via CF,
 DDL or DDK) in randomized order.
The Principal Investigator will inform each patient about procedure, content and measurements
 of the study. It is obligatory that each patient participating in the study gives a written
 informed consent.

 Following an initial incremental shuttle walk test (ISWT) in order to determine the
 individual maximum capacity, patients will perform three endurance shuttle walk tests (ESWT)
 at 85% of the maximal pace. In randomized order, patients will complete one ESWT on CF, one
 on DDL (liquid oxygen) and one on DDC (portable oxygen concentrator). The time between the
 three ESWTs will be 24 hours in order to give enough time for regeneration. All patients will
 use the same oxygen devices (CF: Companion 1000 (CE 0050), Chart Industries, Inc. Garfield
 Heights, Ohio, USA; DD [liquid oxygen]: Caire Spirit 300 (CE 0029), Chart Industries, Inc.
 Garfield Heights, Ohio, USA), DD [portable concentrator]: Inogen G2, California, USA) and
 will carry the oxygen device in a backpack. Continuous oxygen flow in liter per minute will
 be compared to the level of demand delivery (e.g.: 2 l/min CF will be compared to DD level
 2).
Inclusion Criteria:

 -  COPD patients (GOLD stage III to IV) with hypoxemia at rest or during exercise
 (paO2<60mmHg)

 -  Participation in an inpatient pulmonary rehabilitation program (Schön Klinik BGL)

 -  Written informed consent

 Exclusion Criteria:

 -  General exclusion criteria for exercise tests, e.g. acute coronary syndrome, acute
 myo- or pericarditis, acute lung embolism, pulmonary infarction, acute uncontrolled
 heart insufficiency

 -  Signs of acute exacerbation

 -  Any orthopedic or neurological disabilities that prevent patient from walking