Original Article
A Randomized Controlled Trial of the Effect of Fixed-dose Routine Nocturnal Oxygen Supplementation on Oxygen Saturation in Patients with Acute Stroke

https://doi.org/10.1016/j.jstrokecerebrovasdis.2009.02.008Get rights and content

Background

Mild hypoxia is common in patients with stroke, and associated with worse long-term outcome. Oxygen supplementation could prevent hypoxia and improve recovery. A previous study of routine oxygen supplementation showed no benefit after acute stroke, but did not report compliance and the effect on oxygenation. The aim of this study was to assess the effect of routine low-flow oxygen supplementation on oxygen saturation (SpO2) in patients with acute stroke.

Methods

In all, 63 patients with normoxic stroke and no indications for oxygen treatment were randomized to 2 L/min oxygen supplementation via nasal cannulae overnight or to control (room air) within 72 hours of symptom onset. Additional oxygen was given at the discretion of the clinical team, if medically indicated. SpO2 was assessed from 22:00 to 09:00 by pulse oximetry. Compliance with the trial treatment and sleep status were recorded by nursing staff.

Results

In all, 59 patients were confirmed to have had a stroke and available for overnight monitoring. Six (2 oxygen, 4 control) had no or insufficient oximetry data for analysis. The mean nocturnal SpO2 was 2.5% higher in the oxygen group (n = 27) than in the control group (n = 26) (P < .001). More patients on oxygen than control subjects had SpO2 greater than 90% throughout the night (59% v 23%). Patients on oxygen had fewer desaturations than control subjects (oxygen desaturation index 4%, 0.8 v 2.1) (P = .001). Oxygen was found to be in place as prescribed in 71%. Oxygen supplementation was not associated with insomnia or restlessness. No patient in either group was given oxygen for clinical indications.

Conclusions

Nocturnal oxygen supplementation at a rate of 2 L/min increases the mean nocturnal SpO2 by 2.5% and reduces the number of nocturnal desaturations in patients with acute stroke.

Section snippets

Trial Design, Setting, and Participants

This was a randomized, controlled, single-blind study comparing the effects of fixed-dose oxygen supplementation on nocturnal SpO2 with no oxygen. Adult patients with a clinical diagnosis of acute stroke14 who were not moribund were recruited within 72 hours of admission to our university hospital, a large teaching hospital admitting about 800 patients with stroke per year. Patients with an admission diagnosis of stroke or possible stroke were identified by a part time research nurse (S.S.),

Recruitment

In all, 214 successive patients within 72 hours of onset of a first acute stroke who were not moribund were identified from the admissions log and considered for trial inclusion (Figure 1). Of those, 151 (71%) were excluded for the following reasons: oxygen treatment in progress at the time of recruitment (n = 46); and no oxygen treatment in progress at the time of screening, but potential clinical indications for oxygen (n = 33) [e.g., chronic obstructive airways disease (n = 9), chest

Discussion

The results of this study show that oxygen supplementation at a rate of 2 L/min results in a mean increase in nocturnal SpO2 of 2.5%. Oxygen supplementation also reduces the number of desaturations.

Patients in either group spent very little time with SpO2 of less than 90%. This may be a result of the selection criteria, because patients who were hypoxic or had definite indications for oxygen supplementation at baseline were not included. Oxygen supplementation did not reduce the time spent with

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North Staffordshire Medical Institute funded the purchase of the pulse oximeters.

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