Thyromental Height Test as a New Method for Prediction of Difficult Intubation Using Double Lumen Video Tubes

Most of the thoracic surgery interventions require lung isolation techniques. Currently the most commonly used lung isolation techniques are double lumen tubes or single lumen tubes with additional use of bronchial blockers. In both cases fiberoptic bronchoscopy is used for proper placement and maintenance during operation. Recently double lumen video endotracheal tubes were proposed as a new alternative for lung isolation techniques. The double lumen video endotracheal tube differs significantly in size and physical characteristics from standard single lumen endotracheal tube and intubation may prove to be challenging even for an experienced practitioner. Therefore proper prediction of difficult intubation play a crucial role in a clinical setting. Sensitivity and specificity of existing anthropometric scales and tests used for prediction of difficult intubation seem lacking so new methods such as Thyromental Height Test (TMHT) are being introduced. It is based on the height between the anterior border of the thyroid cartilage and the anterior border of the mentum, measured while the patient lies in the supine position with closed mouth. The main objective of the trial is to assess the clinical usefulness of TMHT in prediction of difficult intubation using double lumen video endotracheal tubes in patients scheduled for elective thoracic surgical procedures. The secondary aim is to evaluate the utility of double lumen video endotracheal tubes as a novel method of lung separation.