Differences in the peak cough flow among stroke patients with and without dysphagia

Coughing is an important protective mechanism for keeping the airway clear, and adequate voluntary coughing reduces the risk of aspiration in patients with deglutition disorders. The purpose of this study was to compare the peak cough flow (PCF) of stroke patients with and without dysphagia and to identify the physical and respiratory determinants of PCF.Using a spirometer, we measured and compared the PCFs of 10 stroke patients with dysphagia (SPD), 20 stroke patients without dysphagia (SP) and 10 gender and age matched healthy controls (HC) recruited by using a notice at a clinic and in newspapers. The PCF of the SPD (mean ± SD, 160.1 ± 68.7 l/min) was significantly lower than that of the SP and HC (297.2 ± 114.2 l/min and 462.0 ± 84.4 l/min, respectively; one-way ANOVA, Scheffe's test, P < 0.05). The vital capacity (VC) and inspiratory reserve volume (IRV) of the SPD were lower than those of the HC. Stepwise multivariate regression analysis revealed that IRV and ambulation function (Functional Ambulation Categories, FAC) contributed 50% and 17% to the variance of PCF (P < 0.05), respectively. It is suggested that respiratory function, especially IRV, is important for maintaining PCF in SPD.