Stroke Oxygen Study
Summary
Stroke is a common and disabling condition and there is a
need to find out more about how to treat patients early after the stroke.
Breathing problems frequently occur, and blood oxygen levels often fall below
normal. Such falls can easily be missed, especially at night, and are clinically
significant. Patients with low oxygen levels are less likely to recover well.
Routine oxygen treatment could prevent low blood oxygen levels and subsequent
worsening of the brain damage. We recently completed a pilot study of the effect
of oxygen treatment during the first 72 hours after a stroke which suggested
that oxygen could improve neurological recovery at 7 days and may reduce the
level of disability at 6 months. The
pilot study included 301 patients and was
not large enough to show clinical benefits, but helped us to design this study.
The Stroke Oxygen Study (SO2S) will enrol a much larger number of participants
to confirm or exclude a definite benefit from oxygen treatment. SO2S will recruit 6,600 patients from over
100 hospitals
throughout the UK. Adult patients who have had a stroke within the last 24 hours
before hospital admission will be eligible, if they have been in hospital for no
longer than 24 hours and if, in their doctor’s view, they have no indications
for or against oxygen treatment. Patients will be given information about the
trial and included if they agree to take part and fit the inclusion criteria. Participants will be allocated randomly to one of 3 treatment
groups: Group 1: usual clinical care, oxygen is given when clinically
required Group 2: oxygen treatment overnight for 3 nights Group 3: continuous oxygen treatment for 72 hours The trial treatment will be started immediately after
allocation. If a reason for starting oxygen, increasing or decreasing the dose
develops while the patient is on the study, treatment will be given as
clinically indicated, irrespective of trial group. Outcomes will be assessed by a member of the research team at
the hospital at one week and by postal questionnaire at 3, 6, and 12 months. At
one week we will assess how well the patient has recovered by doing a
standardized neurological examination and comparing the results with those on
admission. The questionnaires will examine subsequent recovery by asking
standard questions shown to be reliable in assessing stroke outcome. These will
include how well the patients have recovered from the stroke, quality of life,
the ability to perform simple activities of daily living (e.g. washing,
dressing, walking) and extended activities of daily living (e.g. cooking,
shopping, driving). In addition to clinical outcomes we will also collect data
which allow us to make a health economic assessment of the costs and benefits of
routine oxygen treatment. Oxygen is used widely in hospitals and in ambulances
throughout the UK. It is a safe and well established treatment. The main adverse
effect is that attachment to the oxygen tubing will restrict mobility. This may
be less of a problem if oxygen is given at night only. Since stroke patients are
most likely to have low blood oxygen levels at night restricting oxygen
treatment to night only may provide oxygen when it is most needed without
interfering with rehabilitation. Since oxygen can be given safely to most stroke patients, is
cheap and easily available, even small longer-term improvements in outcome will
result in significant gains in health and quality of life.