THE EFFECT OF A CERVICAL COLLAR ON THE TIDAL VOLUME OF ANESTHETIZED ADULT PATIENTS

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-e ight patients undergoing anaesthesia via facemask with spontaneous ven tilation were studied. Tidal volume was measured with the airway in th ree different positions, both with and without a collar. The collar ma de no statistically significant difference to tidal volume in any posi tion. Changing support of the airway increased tidal volume both with and without the collar. Patients fitted with an incorrectly sized coll ar may develop upper airway obstruction in the presence of impaired co nsciousness. Experience should be gained in the correct fitting of sem i-rigid collars.