Prediction of difficult intubation.

The incidence of a difficult laryngoscopy or intubation varies from 1.5% to 13%, and failed intubation has been identified as one of the anaesthesia-related causes of death or permanent brain damage. Problems in the airway management can be predicted based on previous anaesthesia records, the medical history of the patient and a physical examination. Several radiological measurements have been reported to be associated with a difficult intubation. The sensitivities of the commonly used bedside tests i.e. the Mallampati classification and the thyromental distance have been reported to be from 42% to 81%, and from 62% to 91%, respectively. The figures for the specificity have varied from 66% to 84% and from 25% to 82%, respectively. The other subjective assessments and objective measurements employed for the prediction of a difficult intubation reach comparable sensitivities and specificities. Evidently, the positive predictive value is improved, if combinations of tests are used.