Cuff overinflation and endotracheal tube obstruction: case report and experimental study

Background: Initiated by a clinical case of critical endotracheal
tube (ETT) obstruction, we aimed to determine factors that
potentially contribute to the development of endotracheal tube
obstruction by its inflated cuff. Prehospital climate and storage
conditions were simulated. Methods: Five different disposable ETTs
(6.0, 7.0, and 8.0 mm inner diameter) were exposed to ambient
outside temperature for 13 months. In addition, every second of
these tubes was mechanically stressed by clamping its cuffed end
between the covers of a metal emergency case for 10 min. Then, all
tubes were heated up to normal body temperature, placed within the
cock of a syringe, followed by stepwise inflation of their cuffs to
pressures of 3 kPa and >= 12 kPa, respectively. The inner lumen
of the ETT was checked with the naked eye for any obstruction
caused by the external cuff pressure. Results: Neither in tubes
that were exposed to ambient temperature (range: -12 degrees C to
+44 degrees C) nor in those that were also clamped, visible
obstruction by inflated cuffs was detected at any of the two cuff
pressure levels. Conclusions: We could not demonstrate a critical
obstruction of an ETT by its inflated cuff, neither when the cuff
was over-inflated to a pressure of 12 kPa or higher, nor in ETTs
that had been exposed to unfavorable storage conditions and
significant mechanical stress.