To the Editor
This is in response to the Letters to the Editor on the subject of postoperative pulmonary edema. In our institution, we have observed and recorded episodes of pulmonary edema in young, strong, healthy patients after suffering airway obstruction following extubation since we started our quality improvement program several years ago. We have assumed for quite some time that the diagnosis was negative pressure pulmonary edema.
We agree with Dr. O’Hara when she states, ‘This happens more in July, when new residents learn how to evaluate awakening and readiness for extubation, but these incidents happen to experienced anesthesiologists as well.’ For several years in our teaching institution, the incidence was around one in 2,000 extubations. In 1988 we contacted an endotracheal tube manufacturer to build a modified endotracheal tube specifically designed to have the capability to deliver topical anesthesia to the upper airway to eliminate or diminish bucking and coughing during emergence from general anesthesia. In subsequent studies which we undertook, we were able to determine that this was the case.’
For the last two years we have been using topical lidocaine prior to emergence and allowed the patients to wake up with the endotracheal tube in place. By doing so we were able to eliminate or greatly minimize bucking, coughing and also (as a by-product) laryngospasm and/or any other form of upper airway obstruction that may result in pulmonary edema. Negative pressure pulmonary edema following laryngospasm was decreased to one in 10,000.
Another by-product has been the decrease and/or elimination of post intubation sore throat, since most of the trauma to the airway is due to bucking and coughing during emergence, especially if the intubation has been smooth and easy.
Marc G. Viguera, M.D.
Head, Department of Anesthesiology The Buffalo General Hospital Buffalo, NY.
ENDOTRACHEAL TUBE constructed to administer local anesthetic solution to the trachea as patient is emerging from general anesthesia. Top: Syringe 0 local anesthetic attached to injection port, entirely separate from cuff pilot tube. Bottom: Injection of local anesthetic through multiple side holes intended to disperse solution and bathe tracheal mucosa prior to emergence to prevent or reduce coughing and bucking thought to lead to, in some cases, postoperative negative pressure pulmonary edema.
Reference
- Shelsky R, Diakun T, Viguera, M. The efficacy of topical lidocaine administered via the Mallinckrodt Niagara endotracheal tube in attenuating bucking and coughing upon emergence from general anesthesia. Rev. Esp. Anesthesiol. Reanim. 1992; 39:316-318