The Role of Ambulatory Oxygen in Improving the Effectiveness of Pulmonary Rehabilitation for Chronic Obstructive Pulmonary Diseases Patients

The study will be a randomised, single-blinded study comparing oxygen with air in Chronic Obstructive Pulmonary Disease (COPD) patients undergoing Pulmonary Rehabilitation (PR).

The study subjects will be patients with a confirmed diagnosis of COPD who have been accepted for PR and who are not hypoxemic at rest, but have exercise-induced desaturation (defined as a fall in oxygen saturations (SaO2) ≥4% to at least <90%, or any fall to a SaO2 <90%) and demonstrate positive improvement with use of ambulatory oxygen as per the British Thoracic Society 2015 Oxygen guidelines. It is standard practice for patients to have this assessment prior to commencing PR and as part of the assessment the flow rate required to increase the SaO2 to ≥90% during exercise will be determined. Patients will be recruited from PR programs at imperial college health care trust hospitals.

The subjects will be randomised to receive either oxygen at the flow rate determined at the initial assessment to a maximum flow rate of 6 litres per minute, or room air. The subjects will then undergo a standard program of PR over 6 - 8 weeks and then undergo reassessment. 20 patients are required in each group to detect a 30% effect size on the 6 minute walk test (6MWT) with 80% power at the 5% significance level and 29 patients in each group to detect a 25% effect with 80% power. Therefore a minimum of 20 patients per group will be included.

Baseline assessments prior to commencing PR will include symptom and quality of life assessments including Borg scale for assessment of breathlessness, Chronic Respiratory Questionnaire (CRQ), COPD Assessment Tool (CAT) and the Hospital Anxiety and Depression score (HAD). A 6 minute walk test (6MWT) will be carried out as this is a widely used and well validated tool to measure exercise capacity. A handheld dynamometer will be used to obtain more detailed measures of quadriceps muscle strength. In addition we will measure activity at home during and after PR using pedometers as this has never been investigated previously.These are simple devices that can be attached to patients and count the numbers of steps during a day and therefore provide an estimate of activity in the home environment. A yamax Digi-walker SW-200 pedometer will be used to count the number of steps taken per day. Patients will be instructed to wear the device on left side of the body all the time, except when sleeping or showering. Pedometer placement was standardised by placing it on the belt or waistband, in the midline of the thigh, consistent with the manufacturers recommendation and with other studies conducted previously. Patients will be record daily step counts on daily diary cards until their final follow up.

The measures of exercise capacity at the follow up assessment will be carried out off oxygen and will be carried out by an observer blinded as to whether they received oxygen or not during PR. All patients will be provided with ambulatory oxygen for domiciliary use after completing PR.