A COMPARISON OF ANESTHETIC TECHNIQUES FOR AWAKE INTUBATION IN NEUROSURGICAL PATIENTS

Two different methods of achieving upper airway anesthesia for awake f iberoptic intubation were prospectively compared in patients undergoin g surgery for cervical spine instability. Forth patients were randomiz ed to either topical anesthesia or nerve block groups. Topical anesthe sia patients were administered nebulized 4% lidocaine (approximately 2 0 ml) via the oropharynx plus a transtracheal injection of 4% lidocain e (3 ml). Nerve block patient underwent bilateral glossopharyngeal and superior laryngeal nerve blocks with 2% lidocaine (0.5-2 ml per injec tion site) plus a transtracheal injection of 4% lidocaine (3 ml). The quality of anesthesia for intubation was graded by observers blinded t o group assignment. Mean arterial pressure, heart rate, Pao2, Paco2, p Ha, SpO2, and plasma lidocaine concentrations were measured during the intubation sequence. Patient recall of intubation and discomfort were assessed during the postoperative period with visual analog scales. T ime required for successful intubation and quality of intubation and d iscomfort were not different between groups. Physiologic values for th e two groups were similar. The mean total dose of lidocaine in the top ical anesthesia group was approximately 2 times greater than that in t he nerve block group (815 versus 349 mg; p < 0.0001). In contrast, mea n plasma lidocaine concentration at initiation of intubation in the to pical anesthesia group was half that of nerve block group (2.16 versus 4.23 mug/ml; p < 0.0001). Ten minutes later there was no difference o f seizures lidocaine concentration between groups. No patients had evi dence of seizures or neurologic change during the procedure. Patients in the topical anesthesia group recalled change during the procedure. There was no difference in patient perception of discomfort during the procedure. Patients in the topical anesthesia group recalled the intu bation better than those in the nerve block group (p = 0.004). Both te chniques for airway anesthesia were found to be similarly safe and eff ective and offer alternatives when patients with cervical spine disord er require awake oral fiberoptic intubation of the trachea.