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Three Part Question

In a [patient presenting to the emergency department with a stroke who does not need resuscitative measures] is [supplemental oxygen better than no oxygen] at [reducing long term disability and mortality]?

Clinical Scenario

A 73 year old woman presents with a six hour history of a left sided hemiparesis. She has a past history of hypertension. On examination she is GCS 15 with a dense left hemiparesis and her basic observations are stable. You wonder whether the use of supplemental oxygen in the acute stage is needed and will have any effect on long term prognosis.

Search Strategy

Medline 1966-10/03 using the OVID interface.
[exp cerebrovascular accident OR cerebrovascular.mp OR stroke.mp] AND [exp oxygen OR exp oxygen inhalation therapy OR oxygen.mp] AND [exp disability evaluation OR disability.mp] LIMIT to human AND English.

Search Outcome

Altogether 22 papers were found of which one directly addressed the 3 part question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Ronning OM & Guldvog B, 1999, Norway	550 patients presenting within 24 hr after stroke onset Exclusion criteria: age <60, onset> 24hr, subdural, subarachnoid, TIA Supplemental oxygen vs no oxygen	RCT (randomised on birth dates)	Disability at 7 months (Barthel Index) Impairment at 7 months (Scandinavian Stroke Scale)	No difference between the 2 groups on disability (p=0.07) or impairment scores (p=0.67)	Quasi –randomised Effects of being treated in a stroke unit
			Survival at 1 year	No statistical significant difference (p=0.3) in survival rates. One year survival greater in control group (72.9% v 68.8%)

Comment(s)

This large, well conducted study shows no statistically significant difference between the two groups. It shows there is no benefit to giving oxygen routinely to stroke patients, and suggests if given to nonhypoxic patients with mild to moderate strokes may in fact increase mortality. The results for severe stroke patients were inconclusive. The authors suggest (based on a small number of animal studies) that this may be due to oxygen free radicals.

Clinical Bottom Line

In nonhypoxic patients with minor or moderate strokes there is no evidence that supplemental oxygen is beneficial.

References

1. Ronning OM, Guldvog B. Should stroke victims routinely receive supplemental oxygen? A quasi-randomized controlled trial. Stroke 1999;30(10):2033-7.