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The Effect of Walking Aids on Exercise Capacity
and Oxygenation- In Elderly Patients with Chronic Obstructive Pulmonary
Disease
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Abstract
Background: high walking frames may improve exercise capacity in
young patients with chronic obstructive pulmonary disease (COPD).
We have assessed the effect of Zimmer, rollator and gutter frames
on 6-min walking distance and on arterial oxygenation during exercise
in elderly patients with COPD.
Methods: 27 out-patients (15 men) aged 70-82 (mean 75) years were
recruited. Exclusions comprised: COPD exacerbation or oral steroid
use within 6 weeks, confusional state, participation in a pulmonary
rehabilitation programme and exercise limitation by other diseases.
Subjects completed 6-min walk tests unaided and with the three frames
on four separate days in random order 30 min after nebulized salbutamol
(5 mg) and ipratropium (0.5 mg) and were accompanied by an investigator
blinded to results of all other walk tests undertaken. Oxygen saturation
(Sa[O.sub.2]) was monitored by finger probe during exercise. Grouped
t-tests were used to compare distances and reductions in Sa[O.sub.2].
Results: Unaided, the mean (SEM) 6-min walk distance was 210 (16)
m and fall in oxygen saturation was 6.0 (1.1)%. Use of a rollator
frame did not significantly affect either of these values. Using
the Zimmer frame reduced the mean distance to 165 (13) m (t=5.2,
P [is less than] 0.001 vs unaided walk) with an Sa[O.sub.2] fall
similar to that recorded during the unaided walk. Using the gutter
frame increased the mean distance to 234 (150) m (t = 3.1, P = 0.004
vs unaided walk) and reduced the fall in Sa[O.sub.2] to 3.7 (0.8)%
(t= 2.3, P = 0.03 vs unaided walk).
Conclusions: gutter frames improve exercise capacity and Sa[O.sub.2]
during exercise in elderly COPD patients who remain symptomatic
on optimal therapy, whereas unwheeled Zimmer frames have a deleterious
effect in such patients.
Introduction
Chronic obstructive pulmonary disease (COPD) is a major cause of
morbidity and disability in elderly people [1]. The main disabling
symptoms are breathlessness and fatigue, both of which lead to reduced
exercise capacity and difficulties in performing activities of daily
living.
Walking aids improve walking distance [2, 3] and breathlessness
[4] in relatively young patients with COPD. These studies [2-4]
included only a small number of patients and did not evaluate the
effect of different frames (wheeled or non-wheeled) on walk distance
in a blinded manner.
We hypothesized that if walking frames were beneficial to patients
with a respiratory disability, much of the benefit would arise from
the ability of the patient to lean on the frame during walking,
thus bracing the accessory muscles of respiration and allowing them
to be engaged in respiratory activities. Such an action would be
facilitated by wheeled walking frames which should therefore have
an advantage over non-wheeled frames. Indeed, we thought it possible
that non-wheeled frames would have a disadvantage because of the
necessary extra muscular activity involved in repeatedly lifting
such frames. The aim of the present study was to assess the effect
of an unwheeled walking aid (Zimmer frame) and wheeled frames (rollator
frame and gutter frame) on the 6-min walking distance and on oxygen
saturation during exercise.
Methods
Elderly COPD patients were referred to the pulmonary rehabilitation
clinic at the geriatric day hospital because of dyspnoea, fatigue,
reduced exercise tolerance and difficulty performing activities
of daily living despite optimum medical therapy. The diagnosis of
COPD was made by history, physical examination and pulmonary function
testing. Spirometric criteria for inclusion were forced expiratory
volume in 1 s ([FEV.sub.1]) of [is less than] 60% of predicted,
[FEV.sub.1]/forced vital capacity (FVC) ratio of [is less than]
60%, and a rise in [FEV.sub.1] of [is less than] 15% following nebulized
salbutamol (5 mg) and ipratropium (0.5 mg).
Patients with COPD who were aged 70 or older were recruited to
the study if they were clinically stable with no change in medication
in the previous month and no hospital admission for respiratory
illness in the previous 6 weeks. Exclusion criteria comprised: acute
or chronic confusion (Hodkinson Abbreviated Mental Test Score [is
less than or equal to] 7/10 [5]), previous experience of the walk
test or current involvement in a pulmonary rehabilitation programme,
uncontrolled cardiac arrhythmia, severe cardiac failure or uncontrolled
ischaemic heart disease or exercise limitation by factors other
than dyspnoea and fatigue (such as visual impairment, musculoskeletal
problems, neurological impairment and peripheral vascular disease).
However, subjects with other disabilities were included if the subjects
themselves considered their respiratory problems to be the chief
cause of their exercise limitation.
The study was approved by ethical committees of Central Manchester
Healthcare Trust and Bury Health Authority, and informed, witnessed,
written consent was obtained from all subjects.
Spirometry was performed using a Compact C spirometer (Vitalograph
Ltd, Buckingham, UK), which was calibrated daily. Patients performed
FVC tests seated and wearing a nose clip. Three reproducible readings
([+ or -] 5% [FEV.sub.1]) were taken at 1 min intervals and the
best result recorded. Predicted values were obtained from the equations
given by Cotes [6]. Exercise capacity was assessed by a 6-min walk
test [7].
Patients attended the geriatric day hospital on four separate
days. Spirometry and reversibility was measured on the first visit.
Each subject performed one 6-min walk test at each visit, either
unaided or with a Zimmer frame, rollator (wheeled frame) or gutter
(high, wheeled) frame in random order. All walk tests were performed
at the same time of day, under identical conditions, 30min after
the inhalation of nebulized salbutamol (5 mg) and ipratropium (0.5
mg), and at least 2 h after the last meal. Repeat walk tests were
monitored by different blinded investigators. Investigators acted
as time-keepers, following (not leading) the patient and carrying
the pulse oximeter (see below). Each walk test was begun at a different
point along the course to minimize the ability of the patient to
compare his or her performance with that in previous tests. Patients
were allowed to rest during the 6 min, but advised that the aim
was to walk as far as possible in the allotted time and that timing
would continue when they were resting.
Exercise-related arterial oxygen desaturation was assessed during
the walk test by a portable pulse oximeter (Pulsox-7, Minolta, DeVilbiss,
Heston, UK) using a finger probe. Baseline oxygen saturation immediately
before the start of the walk test and the minimum saturation during
the test were noted. Exercise-related desaturation (%) was defined
as baseline saturation minus minimum saturation.
Statistical analysis
Paired t-tests were used to compare differences in 6-min walk distance
and oxygen saturation. Significance was defined at the 5% level.
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