The effect of a cervical collar on the tidal volume of anaesthetised adult patients.

Abstract

Semi-rigid cervical collars may be used to assist the stabilisation of the cervical spine during transport in patients suffering from major trauma. We have attempted to evaluate the effect of one such collar on airway patency in the presence of depressed airway reflexes. Thirty-eight patients undergoing anaesthesia via face mask with spontaneous ventilation were studied. Tidal volume was measured with the airway in three different positions, both with and without a collar. The collar made no statistically significant difference to tidal volume in any position. Changing support of the airway increased tidal volume both with and without the collar. Patients fitted with an incorrectly sized collar may develop upper airway obstruction in the presence of impaired consciousness. Experience should be gained in the correct fitting of semi-rigid collars.