Respiratory Muscle Training in Stroke Swallowing Disorders (RETORNUS-2)

The RETORNUS-2 Study: Impact of Respiratory Muscle Training on Swallowing Disorders in Stroke Patients

Clinical randomized clinical trial to assess the effectiveness of incorporating inspiratory and expiratory muscle training (IEMT) in the rehabilitation of stroke patients with dysphagia in terms of functional outcomes, comorbidities, survival and quality of life. This project also incorporates a longitudinal study to assess the clinical impact of dysphagia on body composition and nutritional status in stroke patients.

Stroke is a major cause of morbidity and mortality worldwide. Stroke can lead to varying degrees of oropharyngeal dysphagia (25-85% of patients) and respiratory muscle dysfunction associated with an increase in medical complications such as bronchoaspiration, malnutrition and death. Dysphagia is present in a significant proportion of patients admitted to Rehabilitation (up to 85% depending on series) in stroke. Standard swallow therapy consists of educational intervention aimed to improve self-management of dysphagia and protect the airway, oral exercises to improve lingual praxis, and compensatory techniques based on videofluoroscopic findings. Recent studies suggest that IEMT can improve swallowing efficacy and reduce eventual bronchoaspiration events. Nutritional status appears in 9-67% of patients with acute and subacute stroke and has an impact on functional outcomes and provides information about the risk of hospitalization and death. Stroke patients are at risk of developing malnutrition because of neurologic impairments related to feeding (chewing, deglutition and self-feeding) that can result in a poor food intake. To date, there is only few studies on prevalence and influence of malnutrition in stroke.

Training load will be the maximum inspiratory / expiratory load defined according to patient tolerance equivalent to 10 maximal repetitions (RM) as 10 consecutive inspirations / expirations (x 5 set), three times per day, during 8 weeks. External loads will be increased weekly at intervals of 10 cm H2O as tolerated. Patients will receive standard swallow therapy consisting of swallowing manoeuvres, oral exercises, and compensatory techniques aimed to improve self-management of dysphagia and protect the airway.

Respiratory muscle strength is assessed through maximal inspiratory and expiratory pressures (PImax and PEmax, respectively) using a pressure transducer connected to a digital register system. The PImax is measured at mouth during a maximum effort from residual volume against occluded airway. To determine the PEmax, the patients will perform a maximum expiratory effort from total lung capacity (TLC) in the face of the occluded airway. A specific and validated respiratory pressures manometer will be used (Micro RPM, Cardinalhealth, Kent, UK).

Dysphagia severity is assessed with the Penetration-Aspiration Scale: scores of 1-2 indicate normal swallowing; 3-5, penetration; >6, aspiration.

Lingual Force (IOPI system): maximum isometric tongue pressure defined as the highest of the three peak isometric tongue pressure scores.

Fat-free mass measured by electrical bioimpedance in kilograms and expressed as normal, low or high values according to normal values for the reference population

Inclusion Criteria: First-ever Ischemic or haemorrhagic stroke Time since stroke onset: 1 month Dysphagia confirmed by videofluoroscopic study with a score >3 in the 8-point Penetration Aspiration Scale. Mini-mental State Exploration > 24) Exclusion Criteria: Aphasia History of cardiopulmonary disease; neurologic condition other than stroke and metabolic disease Medical treatment with potential effect on muscle structure and function

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