Breathlessness and

oxygen therapy

Rosemary Moore

Physiotherapist

B App Sc (Physio) Grad Dip Physio (Cardiothoracic)

M Physio (Research) PhD

Take home messages

● Oxygen is a drug used to treat low

blood oxygen levels (hypoxaemia)

● Breathlessness does not always

indicate hypoxaemia

● Oxygen is not a treatment for

breathlessness

Why do we breathe?

Fuel: oxygen Waste: carbon dioxide

(Lavoisier 18th century)

“….. the body has practically

no storage capacity for

oxygen, but depends from

moment to moment for its

supply from the air”

(Haldane 1919)

Why might we feel breathless?

●demand and supply

●MANY possible causes of

excessive breathlessness

* excessive breathlessness not

always associated with

insufficient oxygen

The oxygen transport pathway

Respiratory

System

Circulatory

System

Muscles

(& organs)

Excessive Breathlessness:

some investigations

● Lungs

− Breathing tests (obstructive, restrictive lung

problem)

− Chest X-ray

− CT scan

● Heart

− ECG, angiogram, echocardiograph, 24 hour

monitor

● Exercise tests

● Blood tests

Dyspnoea

● perceived difficulty with breathing

● unpleasant urge to breathe (air hunger)

● breathing discomfort

● sensations of increased inspiratory work or

effort, chest tightness, unsatisfied

inspiration

* Dyspnoea is not always associated

with insufficient oxygen

Cycle of deconditioning

SOB on exercise

deconditioning dyspnoea

avoidance of exercise

inactivity

Hypoxaemia: investigations

● Arterial blood gases

● Pulse oximetry

● Exercise tests – eg. 6 minute walk test

● Oxygen therapy is a drug prescribed to

treat hypoxaemia

− according to guidelines (Australasian)

− to achieve target oxygen saturation range

Acute / emergency oxygen therapy

● In hospital, emergency departments,

ambulance

● To correct hypoxaemia in severely ill

patients

● Target range:

− Australasian guidelines: SpO2 92% to 96%

− or 88–92% in COPD / risk of hypercapnea

(raised blood carbon dioxide level)

Home oxygen therapy

3 main categories

1. Continuous (“Long Term Oxygen Therapy”)

2. Nocturnal oxygen therapy

3. Intermittent oxygen therapy

− Exertional (ambulatory) oxygen therapy

− Air travel

− Palliative: terminal illness + severe dyspnoea

+ significant hypoxaemia

− Acute/life threatening asthma + isolated area

Home oxygen therapy

3 main categories

1. Continuous (“Long Term Oxygen Therapy”)

2. Nocturnal oxygen therapy

3. Intermittent oxygen therapy

− Exertional (ambulatory) oxygen therapy

− Air travel

− Palliative: terminal illness + severe dyspnoea

+ significant hypoxaemia

− Acute/life threatening asthma + isolated area

Continuous oxygen therapy

(LTOT)

● Indications: severe hypoxaemia at rest

−PaO2 55 mmHg

or

−PaO2 56–59 mmHg + hypoxic organ damage:

polycythaemia (blood test)

heart (echocardiograph)

● Aim: PaO2 > 60 mmHg

Continuous oxygen therapy

(LTOT)

● At least 15 hours per day

● Stationary concentrator

−+/- portable cylinders

−? portable concentrator

●Evidence: in COPD

− improves survival

−alleviates hypoxic organ damage

Exertional (ambulatory)

oxygen therapy ● Indication:

−exercise induced hypoxaemia

●Australasian guidelines:

may be considered if

− O2 sat: 88% during exercise

and

− exercise tolerance or dyspnoea

− Six minute walk tests

Exertional (ambulatory)

oxygen therapy

● For use during exertion

●Portable cylinders

● ? portable concentrator

●Evidence: not evidence based

Oxygen therapy –

Contraindications

●Normal oxygenation

● Sub-maximal therapy

●Current smoking

− fire risk

− reduced benefit

● Disinclination

Oxygen therapy – Risks

●Safety

− increased risk of falls

− burns

− death

● Incorrect flow

− hypercapnea (raised blood carbon dioxide)

● Nasal discomfort

Oxygen therapy – Barriers

● Difficulty with equipment

− lack of portability

− changing regulators

● Embarrassment

Take home messages

● Oxygen is a drug used to treat low

blood oxygen levels (hypoxaemia)

● Breathlessness does not always

indicate hypoxaemia

● Oxygen is not a treatment for

breathlessness

References Getting started on home oxygen.

Lung Foundation Australia

HOME OXYGEN THERAPY GUIDELINES

Adult domiciliary oxygen therapy. Position statement of the Thoracic Society of Australia and New Zealand.

McDonald et al. Medical Journal of Australia, 2005; 182(12): 621-626.

British Thoracic Society guidelines for home oxygen use in adults.

Hardinge et al. Thorax 2015;70:i1–i43.

ACUTE / EMERGENCY OXYGEN THERAPY GUIDELINES

TSANZ oxygen guidelines for acute oxygen use in adults. “Swimming between the flags.”

Beasley et al. Respirology 2015; 20: 1182-1191.

BTS guidelines for emergency oxygen use in adult patients. O’Driscoll et al. Thorax 2008;63(Suppl VI):vi1–vi68.

REVIEW ARTICLE

Dyspnoea and oxygen therapy in COPD.

Moore and Berlowitz. Physical Therapy Reviews, 2011; 16(1): 10-18.

When you can’t breathe, nothing else matters