1. Oxygen assessment and provision Anne McGown Consultant Royal Berkshire Hospital Mar 2008

2. Old system • Oxygen concentrators for long term oxygen therapy • some assessment done by chest clinics, but prescription done by GPs • Cylinders for prn use • No provision of ambulatory oxygen

3. New system • Divided according to oxygen requirement, and then company decide most economical system • Long term oxygen therapy • Ambulatory • Short burst • Emergency - indications yet to be defined

4. Therapeutic role of oxygen • Only one of a number of effective treatments for chronic lung disease • Need to have the right diagnosis • Need to optimise other treatments • Has defined indications and is not a universal panacea.

5. Oxygen for breathlessness • No evidence that oxygen treats breathlessness in patients who are not hypoxic either at rest or on exercise. • Why should it?

6. Oxygen dissociation curve • If already on the flat bit no benefit from increased pO2 • (If on the steep bit even low concentrations can help.)

7. Long term oxygen therapy • Continuous oxygen for at least 15hours a day • Survival benefit in persistently hypoxaemic patient • Mainly patients with COPD, other chronic lung disease with hypoxia. • Criteria for prescription based only on blood gas measurements, not symptoms.

8. Who should be assessed? (COPD) • All patients with severe airflow obstruction (FEV1 < 30% predicted) • patients with cyanosis • patients with polycythaemia • patients with peripheral oedema • patients with a raised JVP

9. Pulse oximetry • Can be used to screen who to refer for LTOT assessment • Non-invasive way to monitor percentage of haemoglobin that is saturated with oxygen. • Works because oxygenated haemoglobin is a different colour from deoxygenated haemoglobin. • Selects out pulsatile flow. • Accurate above a saturation of 70%.

10. Pulse oximetry - practical points • Not accurate if signal poor - always need to check signal • probe position • hypovolaemia/shock • peripheral vasoconstriction - cold • shivering • nail varnish

11. Checking the signal

12. Assessment for LTOT • Pulse oximetry saturation <92% • Arterial blood gases on 2 occasions 3 weeks apart when stable (ie not during exacerbation) • Arterial puncture, traditionally performed by doctors in hospitals; we have a hospital protocol for nurse training and 4 nurses currently trained in clinic. • Capillary sampling, easier, less reliable, tends to underestimate oxygen values

13. LTOT prescription • Strict criteria for prescription - pO2 of <7.3 or 7.3 to 8 with signs of cor pulmonale. • Do HOOF if fit the criteria. • Oxygen concentrator 15hours a day, 2l/min • Warn re smoking • Monitor compliance, sats, peripheral oedema • Evidence that it doesn’t help if not that bad.

14. The HOOF and the HOCF

17. Small print • Copies to • PCT • Trust clinical lead for oxygen • GP • patients notes • oxygen company

19. Oxygen concentrators • Concentrate oxygen out of the air (by absorbing other gases) • Plug into the wall, with tubing wired round the house. • Need a cylinder for power cuts etc.

20. Ambulatory oxygen • Provision of oxygen during exercise and activities of daily living. • Shown to be effective in increasing exercise capacity and reducing breathlessness in patients with exercise arterial oxygen desaturation (fall of more than 4% or to below 90%).

21. Ambulatory assessment • New assessment procedure • 6 minute walk, check desaturation • 6 minute walk on oxygen, measure distance, desaturation correction and breathlessness on visual analogue scale. • Time consuming, but less technically demanding than blood gases • Only do assessment if reasonably mobile and motivated to carry the oxygen.

22. Ambulatory assessment • Grade 1 oxygen requirements • on LTOT, walk nowhere, may want portable cylinder for their wheelchair but don’t need assessment • Grade 2 oxygen requirements • active LTOT - need assessment to see what flow rate corrects desaturation • Grade 3 oxygen requirements • exertional desaturation no LTOT

23. Ambulatory referrals • Probably should offer assessment to all severe COPD patients if active enough. • ? Also some moderate COPD patients who are SOBOE • interstitial lung disease + SOBOE • new service so we don’t really know nationally who will end up using it • compliance issues.

24. Short burst oxygen • Prn cylinder patients • no assessment necessary to prescribe short burst (no clear evidence of benefit) • All new patients being considered for short burst oxygen should be referred for ambulatory assessment if mobile and LTOT assessment if hypoxic.

25. Compliance • New system should allow better compliance/usage monitoring and removal of equipment if not used. • Inappropriate short burst prescription should be reduced.

26. Flight assessment