Tracheostomy tube enabling speech during mechanical ventilation.

BACKGROUND: A voice tracheostomy tube (VTT) was developed to enable patients to speak during mechanical ventilation.
METHODS: The VTT has slits cut in it and is covered on part of its side with an elastic cuff, enabling the cuff to expand with positive pressure from the ventilator on inspiration and to deflate on expiration. By this mechanism, inspired air from the ventilator goes to the lung with the cuff inflated, and some of the expired air passes out around the deflated cuff and discharges through the glottis, allowing sufficient ventilation and also enabling vocal fold vibration. An experiment using a model lung showed that there was little leakage on inspiration even for low lung compliance and high airway pressure, and that the leakage volume on expiration was approximately 40% of the ventilated volume, ie, the volume discharging through the vocal fold in clinical use.
RESULTS: Sixteen patients who had been managed by ventilation via a conventional tracheostomy tube were switched to the VTT. All patients except one were able to speak after switching to the VTT without change in PaO(2) and PaCO(2). There were no complications associated with the use of the VTT. Bronchoscopy showed that the cuff of the VTT did not damage the tracheal mucosa.
CONCLUSION: The VTT enables patients to speak during mechanical ventilation with sufficient ventilation and without aspiration and damage to the tracheal mucosa, even in patients with low lung compliance.