Identifying the more patent nostril before nasotracheal intubation

We have studied the reliability of two simple pre-induction tests used to s elect the more patent nostril for nasotracheal intubation by comparing thei r results with those obtained from fibreoptic examination of the nostrils, in 75 maxillo-facial patients requiring nasotracheal intubation under gener al anaesthesia, who had no history of nasal obstruction. The tests comprise d (1) estimation of the rate of airflow through each nostril during expirat ion by palpating the passage of air when the contralateral nostril was occl uded, and (2) asking for the patient's assessment of airflow through the no strils, following the administration of a vasoconstrictor. After each test, noses were classified as left or right nostril clearer or nostrils equally clear. After the induction of general anaesthesia, bilateral nasendoscopie s were performed and videotape recordings of these were later analysed by a n otolaryngologist who had no knowledge of the test results. Intranasal abn ormalities were identified and noses were again classified as left or right nostril clearer or nostrils equally clear. There was no significant differ ence between the overall diagnostic success rates of the two tests (44% and 47%, respectively). In patients with intranasal abnormalities, the numbers of correct diagnoses made by the two tests were not significantly differen t and were also not significantly different front the number of correct sel ections made if only the right nostril or only the left nostril had been us ed for the intubation. In view of the relatively high diagnostic failure ra tes, anaesthetists should not rely on the two tests investigated when selec ting the best nostril for nasotracheal intubation.