Alterations in swallowing and the upper airway flow characteristics can occur after tracheotomy and can result in varying degrees of aspiration. We investigated the effect of a Passy-Muir speaking valve (PMV) on biomechanical properties of swallowing and the upper airway flow characteristics, explored swallowing-breathing interactions preliminarily for tracheotomized patients after acquired brain damage.

Six tracheotomized patients who were able to tolerate the PMV and eight healthy volunteers were recruited. High-resolution manometry (HRM) and videofluoroscopic swallowing study (VFSS) were performed to evaluate the swallowing function of the healthy and patients without and with PMV. Iohexol injection was used. Three-dimensional models of the upper airway were constructed based on the CT-scan data. Pressure in pharynx, which was measured by HRM was used as boundary conditions. Computational fluid simulations were performed to acquire upper airway flow characteristics.

The patient group showed significantly lower upper esophageal sphincter (UES) resting pressure, shorter UES opening times and less hyoid anterior movement (HAM), but significantly higher UES residual pressure, as well as higher airflow velocity and pressure during inspiratory, expiratory, especially swallowing phase. With the PMV, higher UES resting pressure, larger hyoid superior movement (HSM) and UES opening diameter, lower airflow velocity and pressure were observed, the airflow velocity dropped to almost normal level during swallowing phase. However, there was no significant difference of the maximum pharyngeal pressure, UES residual pressure, laryngeal closure times, UES opening times, HAM, or Penetration-Aspiration Scale score before and instantly after wearing the PMV.

The PMV demonstrated significant effects on UES resting pressure, HSM, UES opening diameter, upper airway airflow velocity and pressure in tracheotomized patients after acquired brain damage.