Early laryngeal outcome of prolonged intubation using an anatomical tube: a double blind, randomised study

The objective of this study was to study the short-term impact on larynx by a newly designed anatomical tube. A prospective randomised trial of a newly designed anatomical tube versus a standard endotracheal tube in patients operated under general anaesthesia for at least 12 h. Seventy adults were included and randomised to either type of tube. The patients were evaluated by means of fibre-optic laryngoscopy and VAS-rating of symptoms on two occasions in the first post-operative week. The evaluating investigators and the patients were blinded to the type of tube used. 27 cases and 23 controls had complete data for evaluation. Age, gender and intubation times were comparable. Symptoms such as hoarseness, coughing, and pain were rated above 30 % of maximum during at least one of the first post-operative days by 21 and 19 patients, respectively. At the first examination (within 24 h), 38 % of patients in the anatomical tube group stated no hoarseness; compared to 13 % of the controls (p = 0.057). Fibre-optic laryngoscopy showed some kind of pathology in all the patients examined within 24 h of extubation. After 3-6 days, seven patients with the anatomical tube and four patients in the control group showed complete resolution of the lesions, and the changes were limited to redness in the vocal process area in another seven and four, respectively. The differences between the groups did not attain statistical significance. The study shows considerable short-term laryngeal morbidity after prolonged intubation, and the anatomical tube only showed an advantage concerning hoarseness. Further improvement of the endotracheal tubes and intubation routines are still needed.