Several patient management goals influence anesthetic drug selection in patients undergoing cervical spine surgery for severe cervical spine disease. Two of these are anesthetic choice and dosing technique to facilitate awake airway management and dosing techniques to optimize spinal cord monitoring. This chapter will briefly review some of the techniques, among many, that can be used to achieve these goals.
A 56-year-old, 80-kg (176 lb), 165-cm (5’5”) female with bilateral hand numbness and arm pain is recently diagnosed with 2 cervical herniated discs is scheduled for C5-6, C6-7 anterior cervical discectomy and fusion. Neck and arm pain are exacerbated with neck extension. An awake fiberoptic bronchoscopy is planned for endotracheal tube placement.
Analgesia and Sedation for Awake Fiberoptic Intubation
Attaining optimal intubating conditions for an awake fiberoptic intubation in a patient with a known or suspected unstable cervical spine is a challenge. There are several, sometimes conflicting, goals that include good patient cooperation, adequate analgesia during intubation, minimal cervical spine movement, and adequate cardiopulmonary function. Several pharmacologic options are available to the anesthesiologist to assist in achieving these goals. Selected agents are presented in Table 36–1.
Selected topical anesthetics, sedatives, and analgesics for an awake fiberoptic intubation.
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Table 36–1 Selected topical anesthetics, sedatives, and analgesics for an awake fiberoptic intubation.
|Agent ||Dose ||Comments |
|Topical anesthetics |
|Lidocaine || |
2% or 4% liquid preparation for topical spray or nebulizer
|Maximal dose: 5 mg/kg |
|Benzocaine ||2-second spray ||Excessive dosing may cause methemoglobinemia. |
|Opioids || || |
|Remifentanil || |
Consider 0.25–0.5 mcg/kg bolus to speed onset of effect
|Requires up to 15 minutes to reach pseudo–steady state if dosed only as a continuous infusion |
|Fentanyl ||0.5–1.0 mcg/kg || |
|Midazolam ||0.5–2.0 mg ||Requires up to 5–8 minutes to reach peak effect |
|Dexmedetomidine || |
Consider 0.5-mcg/kg bolus to speed onset of effect
|May cause hypotension |
|Ketamine ||10–20 mg || |
May increase secretions
|Glycopyrrolate ||0.2–0.4 mg ||Antisialagogue |
|Atropine ||0.1–0.5 mg ||Antisialagogue |
The mainstay of analgesia for an awake fiberoptic bronchoscopy is topicalization of cranial nerves IX and X with a local anesthetic. Topicalization works best in a dry mouth and when there is adequate time for the local anesthetics to take effect (up to 20–30 minutes). Common local anesthetics include lidocaine and benzocaine spray.
For topical administration, 5% lidocaine ointment can be applied to a tongue depressor. Patients are asked to suck in the tongue depressor as they would with a lollipop. This approach helps abolish the oral gag reflex. To ablate the periglottic cough, 1 to 2 mL of 4% lidocaine can be administered to the posterior pharynx and supraglottic structures via a microatomizer device. The subglottic cough is ablated via an additionally 2 to 3 mL of 4% lidocaine injected transtracheally or ...