Endotracheal intubation has been identified as a risk factor for anesthesia-related morbidity and mortality in cats.1,2 A contributing factor is overinflation of the endotracheal tube cuff (ETTC), as this puts excessive pressure on tracheal mucosa and can cause pain; mucosal ischemia, ulceration, and tearing; and tracheal stricture, which often results in death. Although seemingly uncommon, these events may occur more often than realized, as anesthetic adverse events are rarely self-reported in veterinary medicine. Airway compromise is a likely cause of sudden death during recovery from anesthesia; in a large mortality study, most of the cats died in the recovery phase of anesthesia, primarily of unknown causes.1 Regardless of frequency, tracheal damage can be a severe adverse effect and should be prevented.
In the present study, 2 methods commonly used to assess appropriate ETTC pressure (ie, palpation of pilot balloon tension, listening for a leak while delivering a self-defined “normal” breath) were evaluated by measuring ETTC pressure after inflation.3 With both techniques, ETTC pressure was significantly and often dangerously higher (range, 36-66 cm H2O) than the pressure generally considered to be safe in cats (ie, 20 cm H2O). In addition, ETTC pressure differed between 2 brands of tubes, each with a cuff of different shape and pilot balloon of different size. Because the techniques used to assess ETTC pressure and the use of different brands of endotracheal tubes in a practice are common in veterinary medicine, overinflation of ETTCs is likely a common occurrence. Conversely, underinflation of ETTCs can also be problematic, as it allows for aspiration of foreign material (eg, regurgitated GI fluid).
In human medicine, special manometers that directly measure ETTC pressure are commonly used.4 A number of products are available, reusable, and relatively inexpensive. Based on
the data reported in this and similar studies,4-6 adoption of means to directly measure ETTC pressure should be strongly considered in veterinary medicine, particularly for cats.