To the Editor:-There are many situations in which monitoring endotracheal tube cuff pressure is desirable. A number of devices have been developed to allow such monitoring. However, one may obtain a continuous digital display of endotracheal tube cuff pressure in the operating room (OR) or intensive care unit using readily available equipment. An ordinary (usually disposable) air-filled pressure transducer is first connected to a pressure channel of an OR monitor, set to zero, and then hooked up to the pilot balloon/cuff inflation line of the endotracheal tube via a stopcock. A 10-mL syringe inserted in the other port of the same stopcock allows air to be added or removed from the cuff as needed. Finally, a male plug ("dead-ender") is placed in the remaining port of the pressure transducer to seal the system (ordinarily this port is hooked up to a high-pressure fluid source to make a flush system).
This concept was tested with satisfactory results in 10 cases using a Baxter (Deefield, IL) disposable pressure transducer in conjunction with the Datex (Instrumentarium Oy; Instrumed, Intrumentarium, Finland) AS/3 OR monitor. However, it can be implemented on any modern OR monitor. Because one pressure transducer can be used for many cases, the system is remarkably inexpensive. If desired, the endotracheal tube cuff pressure waveform can be displayed on the OR monitor or entered into an automatic charting system. When processed appropriately, this signal may yield information related to respiratory timing and other matters.
D. John Doyle, M.D., Ph.D.
Associate Professor; Department of Anesthesia; Toronto Hospital and University of Toronto; Toronto, Canada, M4C-5N4;firstname.lastname@example.org
(Accepted for publication March 12, 1999.)