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Anesth Analg. 1999 Apr;88(4):766-70.

The assessment of four different methods to verify tracheal tube placement in the critical care setting.

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Department of Internal Medicine I, University of Vienna, Austria.


One of the most serious complications of conventional endotracheal intubation is unidentified placement of the tube in the esophagus. The aim of our study was to evaluate four different methods for immediate detection of the tube position: auscultation, capnographic determination of ETCO2, esophageal detection method (EDM) using a self-inflating bulb, and the transillumination method using a lighted stylet (Trachlight; Laerdal, Armonk, NY). Thirty-eight endotracheally intubated patients admitted to our medical intensive care unit were enrolled in the study. A second identical tube was inserted into the esophagus under laryngoscopic control. The endotracheal tube was then disconnected from the ventilator. Two blinded examiners, one experienced, the other inexperienced, determined the tube position within 30 s using one of the four methods. The order of the tubes tested and the methods used were randomized. In 130 of 152 examinations, both examiners correctly diagnosed the position of the tube. The wrong result was obtained by both examiners 4 times; only the experienced examiner was wrong 4 times, and only the inexperienced examiner was wrong 14 times. Using ETCO2, both examiners were correct in all cases. Auscultation showed an obvious relation to the examiner's experience: the experienced examiner was correct in all cases, the inexperienced examiner was correct in only 68% of cases. Using the self-inflating bulb, there were two wrong results of the experienced examiner and one wrong result of the inexperienced examiner. The transillumination technique was associated with a high error rate by both examiners (16% and 13%, respectively). Comparing all four methods showed that capnography is superior to auscultation (P = 0.0005) and to the Trachlight detection method (P = 0.0078). EDM was not statistically superior to auscultation and transillumination. Capnography was the most reliable method for rapid evaluation of tube position, followed by EDM, whereas auscultation and Trachlight did not seem to be of comparable value. Experience was a determining factor for auscultation.


To prevent unidentified esophageal intubation, a serious complication in the critical care setting, four methods for detecting tube position were tested by two examiners (one experienced, the other inexperienced) in endotracheally intubated patients after insertion of a second tube into the esophagus.

[Indexed for MEDLINE]

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