Difficult intubation--when can we predict it?

Anaesthetists at times encounter difficult intubation in an apparently normal individual in spite of using the best possible positioning and most profound relaxation. This study was carried out to find out the most simple and easy measurement that may predict a difficult intubation. The study was conducted in three groups of patients of twenty each. The first group consisted of patients in whom intubation was easy. Second group consisted of anticipated difficult intubation. Cases in whom very difficult intubation was encountered were analyzed retrospectively and were included in third group. An attempt has been made to predict difficult intubation with the roentgenographic study of lateral view of mandible along with the measurement of distance from chin to thyroid cartilage. Of all the parameters, ratio of effective mandibular length to posterior mandibular depth and distance from chin to thyroid cartilage were found to be important to predict difficult intubation.