NONRADIOGRAPHIC, TRANSCUTANEOUS DETERMINATION OF TRACHEAL TUBE POSITION: RESULTS OF MULTICENTER PRE-CLINICAL EVALUATION

Abstract

A new procedure for real time, nonradiographic determination of endotracheal tube position with a magnetic field interference sensing technique was evaluated in cadavers. Each prototype tube incorporates a magnetically detectable marker at a specific distance from its distal tip, which varies with tube size. Transcutaneous determination of tube position is accomplished with a portable instrument that emits visual and aural signals of intensity proportionate to the alignment and proximity of the instrument sensing probe with the tube's magnetic marker. In the preclinical studies the magnetic marker was positioned so that the maximum signal intensities were obtained when the instrument probe was located at the upper edge of the suprasternal notch. Studies were carried out in 25 cadavers adhering to the protocol utilizing six tube sizes. In each case radiographic analysis confirmed distal tip placement to be above the carina, estimated at the 4th/5th vertebral space, and within the middle third of the trachea below the suprasternal notch. We conclude that this method will reduce the need for X-ray confirmation of tracheal tube position in pediatrio patients and that testing in living, intubated infants is warranted.