Decreased diaphragm excursion in stroke patients with dysphagia as assessed by M-mode sonography

Objective: To record diaphragm excursion via M-mode ultrasonography in stroke patients with dysphagia and determine whether they present reduced diaphragm excursion during voluntary cough compared with stroke patients without dysphagia and healthy subjects.

Design: Prospective cross-sectional study.

Setting: University rehabilitation hospital.

Participants: Acute stroke patients with dysphagia (n=23), acute stroke patients without dysphagia (n=24), and healthy control participants (n=27) (N=74).

Interventions: Not applicable.

Main Outcome Measures: Diaphragm motions during quiet breathing, deep breathing, and voluntary coughing were recorded via ultrasonography using M-mode tracing (mm). Maximum inspiratory and expiratory pressures (cmH₂O) and peak cough flow (L/min) during voluntary coughing were measured.

Results: The mean diaphragm movement (mm) of the hemiplegic side for all groups during quiet breathing, deep breathing, and voluntary coughing was 14.8±4.3, 17.6±4.8, and 20.9±3.7 (P<.001); 23.8±7.1, 32.7±10.6, and 44.7±10.3 (P<.001); and 16.8±4.8, 28.5±4.9, and 36.0±8.2 (P<.001), respectively. The differences were statistically significant. Differences were observed in the maximum inspiratory (P<.001) and expiratory (P<.001) pressures and peak cough flow (P=.027) among the 3 groups. Forward selection stepwise regression analysis, which was performed to determine variables that help predict diaphragm excursion during voluntary coughing, showed that the presence of dysphagia explained up to 60% (P<.001) of the hemiplegic diaphragm movement during voluntary coughing in patients with stroke.

Conclusions: M-mode ultrasonography showed that stroke patients with dysphagia have decreased diaphragm excursion and compromised respiratory function during voluntary coughing.