Transtracheal illumination for optimal tracheal tube placement. A clinical study

The tracheas of 420 adult patients were intubated using the tip of a lighted stylet placed inside the lumen of the tracheal tube, just proximal to the tube cuff. The maximum point of transillumination was visible just distal to the cricoid cartilage, with proper cuff positioning. The lighted stylet was also introduced into the oesophagus to see whether transoesophageal illumination could be demonstrated. The intensity of transillumination was measured using a grading system. The distance between the bevel end of the tracheal tube and the carina was determined with a fibreoptic bronchoscope. Tracheal transillumination was graded as excellent in 81% of patients and as good in 19%, when the overhead lights were dimmed and cricoid pressure was applied. Transoesophageal illumination could not be demonstrated in any patient. The mean distance between the tip of the tracheal tube and the carina varied between 3.7 and 4 cm. Transtracheal illumination is a simple, effective and reliable method that can be used during intubation for the recognition of optimal tube placement.