Preparation for Advanced Airway Management: Preparation for Awake Intubation

Awake intubation is a key technique in anesthesia, allowing for the safe management of a patient with signs and predictors of a difficult airway/intubation. It is commonly undertaken electively, but can also be used in an emergency. An appropriate history must be taken, along with review of investigations (e.g CT scan, nasendoscopy), followed by a physical examination and development of a safe management plan. A variety of local anesthetic methods exist for topicalization of the airway (2-4% lidocaine), including nerve blocks (glossopharyngeal, recurrent laryngeal, superior laryngeal) to assist this. Sedation and amnesic techniques commonly include the use of benzodiazepines (midazolam), opioids (remifentanil infusion) and alpha agonists (dexmedetomidine). Knowledge of the side effects of these are paramount, including the cardiac and central nervous system with local anesthetic toxicity. 20% lipid emulsions are available in the event of this. This review contains 4 figures, 5 tables, and 25 references. Keywords: awake flexible bronchoscopic intubation, awake endoscopic intubation, remifentanil, dexmedetomidine, airway anesthesia, glossopharyngeal nerve block, recurrent laryngeal nerve block, superior laryngeal nerve block, local anesthetic toxicity, lipid emulation

Preparation for Advanced Airway Management: Pre-oxygenation and Positioning

Preoxygenation allows a margin of safety prior to establishing control of a patient’s airway. Effective preoxygenation is influenced by careful technique, respiratory physiology, blood oxygen content, and total body oxygen consumption. Total body oxygen consumption is increased in the pregnant, pediatric, and obese populations, making maintenance of oxygenation more difficult during apnea. In addition to a standard facemask, advanced equipment such as high-flow nasal cannula, THRIVE, and various mask variants may be used. Positioning of a patient for advanced airway management affects preoxygenation, respiratory mechanics, and the conditions for establishing a definitive airway. The “triple airway support” maneuver consists of head extension, neck flexion, and protrusion of the mandibular teeth over the upper teeth; and provides effective mechanics for positive-pressure mask ventilation. Patients with potentially unstable cervical spines present additional challenges and, especially in emergency situations, require careful negotiation of priorities. Common maneuvers such as head tilt, jaw thrust, cricoid pressure, and manual in-line stabilization can cause motion in the unstable cervical spine with uncertain effects.  This review contains 7 figures, 5 tables, and 43 references. Keywords: preoxygenation, functional residual capacity, blood oxygen content, alveolar fraction of oxygen, total body oxygen consumption, high-flow nasal cannula, apneic oxygenation, sniffing position, triple airway support maneuver, manual in-line stabilizatio