Successful bite block placement with the laryngeal mask airway (LMA) may seem mundane, but without care and thoughtfulness on the part of the anesthetist, key variables can be missed. The consequences range from minor – the bite block not proficiently performing its designated task – to disastrous – severe pulmonary edema or needless dental or soft tissue damage.
Case Report
A 41-year-old Caucasian female presented for open-reduction, internal-fixation of a left tibial plateau fracture resulting from a direct blow by a cow six days prior to the surgery date. The patient’s only prior medical history included remote hypertension and right axillary artery occlusion repaired a year ago. The patient’s lone current medication was 1 milligram (mg) lorazepam by mouth to be taken the morning of surgery; the patient had been off all antihypertensive prescriptions for two months, with a current baseline blood pressure of 116/72.
In the holding room the patient was medicated with 2 mg intravenous (IV) midazolam and 100 micrograms (mcg) IV fentanyl. Following pretreatment with 100 mg IV lidocaine, intravenous induction was accomplished with 200 mg propofol. A size 4 LMA was placed with ease. Throughout the two-and-a-half hour procedure, the patent remained anesthetized with a combination of volatile (1.4% isoflurane) and periodic IV boluses of fentanyl, for a total of 275 mcg given. Upon completion of the surgery, the isoflurane was discontinued.
During emergence the patent demonstrated sustained masseter rigidity, such that the anteriorly-located soft gauze bite block proved insufficient in preventing the patient from biting the LMA. Although not occluded enough to preclude the delivery of sufficient tidal volumes, the LMA was unable to...
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