A minimally traumatic, intermittently inflated endotracheal cuff

Synchronized intermittent mandatory insufflation of the endotracheal tube cuff

Continuous inflation of endotracheal tube cuffs causes tracheal injury in up to 11% of intubated patients. To avoid this complication and its consequences of tracheal and laryngeal stenosis and tracheoesophageal fistula, we designed a simple device which enables intermittent inflation of the cuff during inspiratory periods of mechanical ventilation. This was achieved by connecting the inlet of the cuff of the pressure regulating tubing of the expiratory valve of a Bennett respirator. We have used the device in 25 patients with prolonged intubation. There was no air leak around the tube, no aspiration of gastric content, and no late complications as shown by direct laryngoscopy at 1 week, 1 month, and 3 months after extubation, and by X-ray of the upper airway.

Cuffed endotracheal tubes: mucosal pressures and tracheal wall blood flow

Eighteen brands of cuffed endotracheal tubes, including those with the new low pressure cuffs, were evaluated and compared. Experiments were performed in vitro on excised dog tracheae to measure the mucosal pressure exerted by the inflated cuffs. Pressure was measured directly with a mechanical sensor. Latex cuffs exerted the highest mucosal pressures, whereas silicone cuffs exerted the lowest mucosal pressures. Polyvinyl chloride cuffs exerted intermediate levels of mucosal pressure. With each material, predistended cuffs exerted lower mucosal pressures than nonpredistended cuffs. A second set of experiments was performed in vivo to determine the effect of mucosal pressure on tracheal wall blood flow. These studies employed a thermistor technic. The data showed that, when inflated sufficiently to seal within the trachea, stiff cuffs reduced blood flow more than compliant cuffs. With all cuffs, blood flow was reduced more at the mucosa than at deeper regions of the tracheal wall.It was concluded that for clinical use, compliant cuffs are preferable to stiff cuffs because they should cause less ischemia.