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Three Part Question

In [patients with acute heart failure] does [supplemental oxygen] improve [survival and complication rates]?

Clinical Scenario

A 76y old gentleman with a known history of ischaemic heart disease presents with a history of recent onset of severe dyspnoea. On questioning a history is revealed of mild exertional dyspnoea, orthopnoea and paroxysmal nocturnal dyspnoea. On arrival in the department the gentleman had been started on high-flow oxygen via a mask with a reservoir. You wonder if there is evidence to support the use of supplemental oxygen in patients with heart failure.

Search Strategy

Medline 1966 - October 2005 using Ovid interface.
[exp heart failure, congestive OR exp atrial natriuretic factor OR heart failure.mp OR congestive cardiac failure.mp OR ccf.mp OR CHF.mp OR shortness of breath.mp. OR exp ventricular dysfunction, left OR lvf.mp OR exp dyspnoea OR echocardiography OR acute dyspnoea.mp OR exp pulmonary oedema OR pulmonary oedema.mp] AND [oxygen OR oxygen therapy.mp OR exp oxygen OR oxygen therapy.mp OR exp oxygen inhalation therapy OR supplemental oxygen.mp OR O2.mp] AND [treat$.mp] LIMIT to English language and humans.
Embase through Dialog Datastar interface 1974 - October 2005
[heart ADJ failure OR heart-failure#.DE OR congestive-heart-failure#.DE OR ccf OR ventricular ADJ dysfunction OR heart-left-ventricle-failure#.DE OR heart-ventricle-function#.DE OR heart-right-ventricle-function#.DE OR heart-right-ventricle-failure#.DE OR lvf OR cardiac ADJ insufficiency or failing ADJ heart OR heart-edema.DE OR pulmonary ADJ edema OR lung-edema#.DE OR pulmonary ADJ oedema] AND [oxygen] AND [treat$] LIMIT to English language and humans.

Search Outcome

428 papers found from Medline search of which none were relevant.
231 papers found from Embase search of which none were relevant.

Comment(s)

The use of supplemental oxygen in treating patients with acute heart failure is universally accepted and recommended by the American Heart Association and European Society of Cardiology. Despite this there is little evidence of its efficacy in these patients. One small study looking at patients with stable but severe heart failure (Haque W et al 1996) suggests that supplemental oxygen decreases cardiac output and increases vascular resistance. This has also been suggested by studies using animal models. The benefits of supplemental oxygen in the hypoxic patient with heart failure are likely to be significant but there may be detrimental effects in rendering patients hyperoxic.

Clinical Bottom Line

Supplemental oxygen is recommended in the treatment of patients with heart failure who are hypoxic. Hyperoxia may cause further impairment of cardiac function.