Incidence and predictive factors of diaphragmatic dysfunction in acute stroke.

Background: The most characteristic clinical signs of stroke are motor and/or sensory involvement of one side of the body. Respiratory involvement has also been described, which could be related to diaphragmatic dysfunction contralateral to the brain injury. Our objective is to establish the incidence of diaphragmatic dysfunction in ischaemic stroke and analyse the relationship between this and the main prognostic markers.

Methods: A prospective study of 60 patients with supratentorial ischaemic stroke in the first 48 h. Demographic and clinical factors were recorded. A diaphragmatic ultrasound was performed for the diagnosis of diaphragmatic dysfunction by means of the thickening fraction, during normal breathing and after forced inspiration. Diaphragmatic dysfunction was considered as a thickening fraction lower than 20%. The appearance of respiratory symptoms, clinical outcomes and mortality were recorded for 6 months. A bivariate and multivariate statistical analysis was designed to relate the incidence of respiratory involvement with the diagnosis of diaphragmatic dysfunction and with the main clinical determinants.

Results: An incidence of diaphragmatic dysfunction of 51.7% was observed. 70% (23 cases) of these patients developed symptoms of severe respiratory compromise during follow-up. Independent predictors were diaphragmatic dysfunction in basal respiration (p = 0.026), hemiparesis (p = 0.002) and female sex (p = 0.002). The cut-off point of the thickening fraction with greater sensitivity (75.75%) and specificity (62.9%) was 24% (p = 0.003).

Conclusions: There is a high incidence of diaphragmatic dysfunction in patients with supratentorial ischaemic stroke which can be studied by calculating the thickening fraction on ultrasound. Among these patients we have detected a higher incidence of severe respiratory involvement.