Accuracy of flexible fiberoptic endoscopy in identifying abnormal endotracheal tube positions

This study was carried out to investigate the accuracy of a simple, nonmaneuverable, flexible fiberoptic catheter in identifying both normal and abnormal endotracheal tube (ETT) positions. In addition, the utility of flexible fiberoptic endoscopy (FFE) for ETT position determination in inexperienced hands was examined. One adult dog was sedated and instrumented in the esophagus and trachea with identical ETTs. Four possible ETT positions (trachea, carina, bronchus, esophagus) were randomly assigned. One investigator positioned the ETT into the assigned position by fluoroscopy. Four other blinded investigators were asked to determine the ETT position using the fiberoptic catheter. Each blinded investigator was given 15 seconds to complete the examination and record the ETT position. Randomization resulted in 25 ETT positions examined by each of the four blinded investigators for a total of 100 FFE determinations. FFE ETT determination was correct in 97% of the examinations. All esophageal intubations were correctly identified. Two tracheal locations were misdiagnosed as carina and bronchial, while one carinal location was incorrectly judged as tracheal. The sensitivity of FFE ETT localization was 91.7%, and the specificity was 98.6%. There was no difference in performance by investigator training level or endoscopy experience. We conclude that FFE is a rapid and accurate method for determining both normal and abnormal ETT locations. ETT position determination can be confidently performed by health professionals with minimal training.