Oxygen for IPF Simon Johnson

What is oxygen for? Oxygen is needed to generate energy for all body functions –Muscles walking, lifting, dressing etc. –Brain consciousness, thinking Normally oxygen levels are stable no matter how much exercise you do Symptoms of low oxygen –Breathlessness –Fatigue –Cyanosis –Fluid retention

Oxygen uptake from the lungs

Exercise increases oxygen extraction from the blood muscles O2O2 comfortable ‘normal’ breathless faint cyanosed

How is this related to IPF? IPF reduces transfer of O 2 from the lungs to the blood Desaturation to <88% during 6 min walk predicts outcome –independent of age, sex, smoking, lung function and CT scores Decreased overnight saturation associated with reduced daytime energy and social functioning A low O 2 causes frightening symptoms

Who needs oxygen therapy? Not everyone with IPF Not everyone who gets breathless Those limited by low blood oxygen –walking outside / gardening –around the house –at night –all or most of the time

British Thoracic Society guidelines In the absence of suitable controlled studies…………….. …. patients with persistent resting hypoxaemia and who are breathless should be considered for oxygen at home delivered by oxygen concentrator. …… may also benefit form ambulatory oxygen if they remain active outside the home. Patients who are not chronically hypoxic but who are breathless, mobile and exhibit desaturation on exercise (90%) should be considered for ambulatory oxygen if improvement in exercise capacity and/or less breathlessness can be demonstrated by formal ambulatory oxygen assessment. Intermittent supplemental oxygen for periods of 10–20 min may relieve breathlessness associated with hypoxaemia in patients with ILD who do not require oxygen concentrator or ambulatory oxygen. When prescribing oxygen, individually titrate oxygen therapy according to oxygen saturations measured during normal activity. Nocturnal hypoxaemia is common in patients with IPF and may be associated with daytime impairment of quality of life, but there is no evidence that supplemental oxygen is useful in this setting. Clinical trials are required ……………….

How can you tell who needs oxygen? Blood gas test –gives information on O 2 and CO 2 –usually done at rest –doesn’t predict what happens on exertion Six minute walk test –gives information on O 2 and exercise capacity –well validated and predicts prognosis –time consuming and hard work Corridor walk test –easy and predicts need for ambulatory O 2

Corridor walk test pre walk minimum SaO 2

24 hour O 2 saturation O2O2 pulse 7am 7pm7am awakeasleep

Patient diary

Summary data Only 20 minutes with saturation in ‘red zone’ Good values overnight Discuss need for ambulatory O 2

Long term O 2 –>15 hours / day Overnight O 2 Short burst Ambulatory Different types of O 2 therapy

Conserving devices –double duration of cylinder use Portable concentrators –small, –fewer features, usually 2l only Longer lasting systems

Issues with O 2 therapy for IPF Most evidence for O 2 therapy comes from COPD –Gas exchange and O 2 requirements are different –Prescribing O 2 in IPF is different Not always practical around the home ‘I don’t want to get addicted to it’ Feeling self conscious about using O 2 in public

Conclusions Need for O 2 is independent of lung function –more likely in patients with advanced disease O 2 best prescribed after assessment on exertion and at night O 2 can improve social functioning Various systems are available according to need and lifestyle

Any questions?

Travel >95% : fine <92% : supplementary in-flight oxygen 92-95% : flight assessment –15 mins of 15% oxygen