NEON: North East Oxygen Network study

To assess the feasibility of the proposed randomised control trial in the following regard:
1. Prevalence of hypoxaemia in patients with NYHA III/IV and optimal medical therapy. Assessment of arterial oxygenation by:
1.1. Arterial saturation by pulse oximetry at baseline and at the completion of the 6 minute walk test
1.2. Overnight oximetry using the Embletta® to record (i) nadir of oxygenation overnight (ii) proportion of night time spent with oxygen saturation below 95%
2. Recruitment and retention of study patients and their compliance with trial intervention. Criteria for proceeding to the larger RCT phase of the study:
2.1. Recruitment rate >= 3 patients per week per centre during the recruitment phase
2.2. Drop out rate (excluding deaths) of <= 15% at 3 months
2.3. Compliance >= 27%
Number of hours of oxygen used will be measured by concentrator meter and patient diaries.
3. The value of the intervention for a preliminary cost-effectiveness analysis: Minnesota Living with Heart Failure (MLwHF) quality of life questionnaire scores at baseline, 1 and 3 months.
4. To develop a cost-effectiveness model of HOT based on existing evidence (to asses the likely benefit of proceeding to the larger RCT phase of the study)
5. Expected value of perfect information (EVPI) associated with the data to be collected in the proposed trial, that is, whether the patient benefits from the improvement in treatment decisions possible with the additional information provided by the trial is worth the cost of undertaking a definitive clinical trial of this intervention. To use this to inform the design of the subsequent main trial.

1. To assess the effect of HOT delivered as NOT or LTOT on the following:
1.1. Symptoms (total duration of follow-up: 3 months):
a. Assessed using the results of standard biochemistry tests
b. 6 minute walk test
c. Prevalence of hypoxaemia results
d. Validated Borg score and Numerical Rating Scale (NRS) for breathlessness (average and worse over past 24 hours and current level)
d. Change in validated Karnofsky performance scale of physical activity
e. Epworth Sleepiness score to assess daytime somnolence
f. Co-morbidity measured by the Charlson co-morbidity index
1.2. Quality of life, as measured by MLWHF, Hospital Anxiety and Depression (HAD) (mood assessment) and EuroQoL questionnaires at baseline, 1 and 3 months
1.3. Disease severity in patients with CHF, as measured by the validated Borg score and NRS for breathlessness (average and worse over past 24 hours and current level). Total duration of follow-up: 3 months
2. To assess the cost-effectiveness of HOT (see 3 in Primary outcome measures)
3. To assess the acceptability to patients and carers of study intervention and placebo device (Patient diary at enrolment, 1 and 3 months)
4. To assess the acceptability of the placebo device to clinicians (through communications with the research teams)