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A pilot study of respiratory muscle training to improve cough effectiveness and reduce the incidence of pneumonia in acute stroke: study protocol for a randomized controlled trial

Stefan Tino Kulnik1*, Gerrard Francis Rafferty2, Surinder S Birring3, John Moxham4 and Lalit Kalra5

Author Affiliations

1 Stroke Research Team, Department of Clinical Neuroscience, Institute of Psychiatry, King’s College London, PO Box 41, Denmark Hill, London SE5 8AF, UK

2 Department of Respiratory Medicine and Allergy, School of Medicine, King’s College London, Chest Unit, Cheyne Wing, King’s College Hospital, Denmark Hill, London SE5 9RS, UK

3 Division of Asthma, Allergy & Lung Biology, School of Medicine, King’s College London, Chest Unit, Cheyne Wing, King’s College Hospital, Denmark Hill, London SE5 9RS, UK

4 Department of Respiratory Medicine and Allergy, King’s Health Partners, Chest Unit, Cheyne Wing, King’s College Hospital, Denmark Hill, London SE5 9RS, UK

5 Stroke Research Team, Department of Clinical Neuroscience, Institute of Psychiatry, King’s College London, PO Box 41, Denmark Hill, London SE5 8AF, UK

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Trials 2014, 15:123  doi:10.1186/1745-6215-15-123

Published: 12 April 2014

Abstract

Background

After stroke, pneumonia is a relevant medical complication that can be precipitated by aspiration of saliva, liquids, or solid food. Swallowing difficulty and aspiration occur in a significant proportion of stroke survivors. Cough, an important mechanism protecting the lungs from inhaled materials, can be impaired in stroke survivors, and the likely cause for this impairment is central weakness of the respiratory musculature. Thus, respiratory muscle training in acute stroke may be useful in the recovery of respiratory muscle and cough function, and may thereby reduce the risk of pneumonia. The present study is a pilot study, aimed at investigating the validity and feasibility of this approach by exploring effect size, safety, and patient acceptability of the intervention.

Methods/design

Adults with moderate to severe stroke impairment (National Institutes of Health Stroke Scale (NIHSS) score 5 to 25 at the time of admission) are recruited within 2 weeks of stroke onset. Participants must be able to perform voluntary respiratory maneuvers. Excluded are patients with increased intracranial pressure, uncontrolled hypertension, neuromuscular conditions other than stroke, medical history of asthma or chronic obstructive pulmonary disease, and recent cardiac events. Participants are randomized to receive inspiratory, expiratory, or sham respiratory training over a 4-week period, by using commercially available threshold resistance devices. Participants and caregivers, but not study investigators, are blind to treatment allocation. All participants receive medical care and stroke rehabilitation according to the usual standard of care. The following assessments are conducted at baseline, 4 weeks, and 12 weeks: Voluntary and reflex cough flow measurements, forced spirometry, respiratory muscle strength tests, incidence of pneumonia, assessments of safety parameters, and self-reported activity of daily living. The primary outcome is peak expiratory cough flow of voluntary cough, a parameter indicating the effectiveness of cough. Secondary outcomes are incidence of pneumonia, peak expiratory cough flow of reflex cough, and maximum inspiratory and expiratory mouth pressures.

Discussion

Various novel pharmacologic and nonpharmacologic approaches for preventing stroke-associated pneumonia are currently being researched. This study investigates a novel strategy based on an exercise intervention for cough rehabilitation.

Trial registration

Current Controlled Trials ISRCTN40298220

Keywords:
Respiratory muscle training; Prevention; Pneumonia; Stroke; Cough; Rehabilitation