Reuters Health Information 2004. © 2004 Reuters Ltd.

NEW YORK (Reuters Health) Mar 19 - In mechanically ventilated patients who require a cuffed tracheostomy tube to prevent air leakage during inspiration, a modified cuff that deflates on expiration enables patients to speak, a Japanese researcher reports in the March issue of Chest.

Patients with low lung compliance cannot afford to have air leaking during inspiration, and so a cuff is needed to provide adequate ventilation. To permit speech during mechanical ventilation in nonsedated patients with respiratory failure, Dr. Hiroaki Nomori at Saiseikai Central Hospital in Tokyo developed the voice tracheostomy tube (VTT).

The tube is constructed of polyvinyl with two 10-mm slits along its sides. The edges of an elastic polyurethane cuff are bonded to the tube on either side of the slits. Because it expands during inspiration, all the air from the ventilator is sent to the lung. During expiration, the cuff deflates and about 40% of the air is discharged to the upper airway.

After testing the VTT on a model lung and trachea, Dr. Nomori switched 16 patients from a conventional tracheostomy tube to the VTT. Indications for ventilation were chronic obstructive pulmonary disease, sequelae of tuberculosis infection, pneumonia, amyotrophic lateral sclerosis or ventilation insufficiency due to spinal cord injury.

All but one patient, whose trachea was deformed due to long-standing TB, were able to speak. Two patients whose voices were weak required a speaking valve between the VTT and the end of the ventilator circuit.

Blood gas levels did not change after the switch. The VTT approach was used for up to 386 days and there were no cases of aspiration and the slits did not become occluded with secretions. Furthermore, bronchoscopy conducted in 6 patients showed no tracheal damage. In fact, one patient seemed to have improved tracheal mucosal blood flow.

Chest 2004;125:1046-1051.