Awake tracheal intubation

INTRODUCTION — Awake tracheal intubation (ATI) involves placing an endotracheal tube in a spontaneously breathing, awake or lightly-moderately sedated patient, most commonly with a flexible intubating scope or video laryngoscope. ATI should be considered for patients with predicted difficulty with airway management or who may not tolerate the apneic phase following neuromuscular paralysis.

This topic will discuss patient preparation and techniques for ATI. Approach to the management of the difficult airway, including the decision to perform awake intubation, is discussed separately.

●(See "Approach to the difficult airway in adults for emergency medicine and critical care".)

●(See "Management of the difficult airway for general anesthesia in adults".)

DECISION TO PERFORM AWAKE INTUBATION — Tracheal intubation is typically performed in an unconscious patient (ie, after receiving an induction dose of an anesthetic agent). Awake tracheal intubation (ATI) should be considered in patients with predicted difficulty with airway management, and in other patients who would benefit from maintaining spontaneous ventilation, intrinsic airway tone, or airway protective reflexes until an endotracheal tube is placed and mechanical ventilation is started [1]. ATI should also be considered in patients who are at risk for cardiovascular decompensation with administration of induction agents, particularly in the emergency department or in the intensive care unit (ICU).

The decisions to perform ATI for anesthesia and in the emergency department or the ICU are discussed separately, and appear in the 2022 American Society of Anesthesiologists guidelines for difficult airway management [1], the 2021 Canadian Airway Focus Group guidelines [2], and in difficult airway algorithms (algorithm 1 and algorithm 2).

●(See "Management of the difficult airway for general anesthesia in adults", section on 'Awake intubation'.)

●(See "Approach to the difficult airway in adults for emergency medicine and critical care", section on 'Decision to perform awake intubation'.)

ATI is distinct from an awake flexible nasopharyngolaryngoscopic airway examination performed as part of a difficult airway assessment (eg, suspected laryngeal mass) or in a patient unlikely to need tracheal intubation, which is discussed separately. (See "Approach to the difficult airway in adults for emergency medicine and critical care", section on 'Awake airway examination'.)

CONTRAINDICATIONS AND PRECAUTIONS — The absolute contraindication to awake tracheal intubation (ATI) is patient refusal despite explanation of the benefits and risks of the procedure. We avoid ATI in the following as it may be difficult, impossible, or ultimately less safe than a well-prepared rapid sequence intubation with a rigid laryngoscope and clear backup plans for rescue oxygenation:

●Patients who require immediate intubation – When there is little or no time to perform ATI (eg, profound uncorrectable worsening hypoxemia or rapidly progressive upper airway swelling), the "forced to act" principle is invoked [2]. In this situation, a rapid sequence intubation (RSI; also called rapid sequence induction and intubation [RSII]) should be performed instead of ATI, despite anticipated anatomic challenges, as it offers the best opportunity to secure the airway immediately [3,4].

●Patients who are uncooperative or combative

●Patients with local anesthetic allergy

●Patients with excessive airway bleeding or secretions, which may obscure the view during laryngoscopy

●Lack of availability of a clinician experienced in awake intubation or the necessary equipment

CHOOSING THE APPROACH

Visualization device — Awake tracheal intubation (ATI) is usually performed with either a flexible intubating scope or a video laryngoscope (VL). Awake direct laryngoscopy and blind intubation are very rarely used and are not described here.

The choice of intubating device is based on patient factors, clinician expertise, and availability of equipment. Neither flexible scope intubation nor VL is successful 100 percent of the time; clinicians should maintain skills in using both devices for ATI. This is particularly important for flexible scope intubation since use of a flexible intubating scope for airway management is less common. Examples of considerations when choosing the intubation device include the following:

●Flexible scope intubation is used for nasal intubation and may be preferred for oral intubation in patients with very restricted mouth opening, large oral or hypopharyngeal masses, or fixed flexion deformity of the neck.

●VL intubation may be preferred in patients with airway bleeding. Conventional blade VLs (eg, Macintosh style blade) may be particularly useful because they allow direct laryngoscopy if the camera is obscured by blood.

●Awake VL intubation typically requires more complete anesthesia (nerve block or topical) or a deeper degree of sedation compared with ATI with a flexible intubating scope [5]. In patients with a strong gag reflex, glossopharyngeal nerve blocks may facilitate awake VL intubation.

Reported success rates and adverse events are similar after ATI with VL compared with flexible intubating scope:

●ATI for anesthesia – Reported success rates are high for ATI with both VL and with flexible intubating scope for anesthesia. In a 2018 meta-analysis of 8 trials (429 patients) that randomly assigned patients with known or predicted airway difficulty to use of VL versus flexible intubating scope for awake oral or nasal intubation for elective surgery, the rates of first attempt success, failure of intubation with the initial technique, and patient satisfaction were similar in the two groups [6]. Intubation success was >96 percent with the first used device whether VL or flexible scope was used first. Limited adverse events were reported; the incidence of hoarseness or sore throat and oxygen desaturation were similar in the two groups.

●ATI in the emergency department (ED) – Data are limited regarding devices used for ATI in the ED. In a multi-center ED registry (the National Emergency Airway Registry [NEAR]), ATI (defined as an intubation attempt after either topical anesthesia alone or topical anesthesia combined with sedation) was performed in fewer than 0.5 percent of all intubations [7]. Flexible scopes were used in the majority of ATIs (78 percent). The overall first attempt success rate was 85 percent; all patients were ultimately intubated, with one patient requiring a surgical airway. For patients intubated with a flexible scope, first attempt success was greater with nasal compared with oral intubation (91 versus 73 percent). The first attempt was successful in 89 percent of patients intubated with a VL. Conclusions are limited by the small number of patients intubated awake.

Nasal versus oral route — We prefer the oral route for flexible scope intubation unless the patient has trismus or an obstructive lesion of the oral cavity. The choice between nasal and oral intubation is usually dictated by clinical circumstances and the visualization equipment (ie, VL is always oral route). This choice for flexible scope intubation is discussed in detail separately. (See "Flexible scope intubation for anesthesia", section on 'Overview'.)

PREPARATION

Checklists — Awake tracheal intubation (ATI) requires careful planning and diligent preparation. Because it is performed infrequently, using a checklist or cognitive aid may improve performance and ensure that important steps are not missed. Some authors of this topic use the checklist and cognitive aids for planning ATI and for managing complications that appear in the guidelines for awake intubation from the Difficult Airway Society in the United Kingdom [8].

Materials and equipment — Prior to beginning the procedure, confirm that equipment for anesthetizing the airway, managing a difficult airway, and visualizing the airway (flexible intubation scope or laryngoscope) are readily available and operational (table 1). (See "Flexible scope intubation for anesthesia", section on 'Equipment' and "Video laryngoscopes and optical stylets for airway management for anesthesia in adults", section on 'Videolaryngoscopy'.)

When setting up the position of equipment and personnel, ergonomic factors should be optimized as best possible with the goal of immediate access.

●The operator's line of sight should align with the airway management device (flexible scope or laryngoscope), patient, and device screen.

●The patient's physiologic monitors should be immediately visible.

●Check that the supplemental oxygen delivery device and suction are working.

●Ensure that the anesthesia machine or ventilator is available and operational.

●Any airway management equipment that are part of the rescue plan should be readily available.

Personnel — Whenever feasible, a second clinician (separate from the airway operator) should administer sedation and monitor the patient. This will decrease the risk of cognitive overload and allow the primary operator to focus on the ATI procedure. If a flexible intubating scope is being used, ideally an assistant who is familiar with the equipment should be present. The assistant, if available, can facilitate the provider's access to the equipment as needed. Prior to starting the procedure, individual roles for the team members should be assigned, communicated, and confirmed.

PATIENT PREPARATION — Thoroughly informing the patient and securing patient cooperation maximizes the chance of a successful awake tracheal intubation (ATI). The patient should be counseled on the rationale for the procedure and what to expect, emphasizing patient safety and comfort.

Antisialagogues — We suggest administering glycopyrrolate prior to ATI to minimize secretions. Even small amounts of secretions can impair airway visualization by a flexible intubating scope or video laryngoscope (VL). Secretions can also decrease the efficacy of topical local anesthetics [9]. We administer glycopyrrolate 0.2 mg intravenously (IV) 15 to 30 minutes before beginning the procedure if time permits [10]. We do not delay applying topical anesthesia if glycopyrrolate is not readily available and do not use glycopyrrolate if time is limited.

Nasal vasoconstrictors — Prior to awake nasal intubation, we suggest applying a topical vasoconstrictor (oxymetazoline or phenylephrine) to the nasal passages to reduce the risk of bleeding and enlarge the caliber of the nasal passages [11]. We apply nasal vasoconstrictors prior to oral intubation as well if nasal intubation would be a viable backup plan should oral intubation fail.

Commercially available nasal decongestants containing either oxymetazoline 0.05% or phenylephrine 0.5% may be used to constrict the vessels of the nasal mucosa. Some authors of this topic prefer oxymetazoline because it may be a more potent vasoconstrictor compared with phenylephrine [12]. We administer two sprays of oxymetazoline or phenylephrine to each nostril for vasoconstriction at the same time as antisialagogue administration. (See "Flexible scope intubation for anesthesia", section on 'Nasal preparation'.)

Aspiration prophylaxis — For patients at high risk of aspiration (table 2), we take measures to prevent aspiration or mitigate risk should aspiration occur, such as the following:

●Especially in a patient with a full stomach, ensure a smooth course, avoiding gagging, coughing, and vomiting. Whenever possible the intubation should not be rushed, and adequate time should be allowed for optimal anesthetic effect.

●Position the patient head up, either sitting or ramped.

●If time permits, pre-medicate with antacids (eg, famotidine 20 mg IV, sodium citrate 30 mL orally) and/or prokinetic agent (eg, metoclopramide 10 mg IV). For maximal effect, famotidine and metoclopramide should be given at least 60 minutes prior and sodium citrate can be given just prior to induction. Premedication for aspiration prophylaxis is not routinely performed in the emergency department (ED) or intensive care unit, as supporting evidence is limited; the rationale and evidence are discussed separately [13,14]. (See "Rapid sequence induction and intubation (RSII) for anesthesia", section on 'Premedication' and "Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications", section on 'Aspiration'.)

●Maintain airway protective reflexes. Airway anesthesia can compromise airway protective reflexes. In patients at high risk of aspiration, we avoid laryngeal and subglottic anesthesia until immediately prior to delivering the endotracheal tube. During flexible scope intubation, this can be accomplished by spraying local anesthetic solution through the flexible intubating scope as it is advanced during the process of laryngoscopy and intubation. During awake VL intubation, this can be accomplished using a laryngotracheal mucosal atomization (LTA) device.

Monitoring — Patients undergoing ATI must have basic physiologic monitoring, including pulse oximetry, blood pressure monitoring, and cardiac monitoring. We recommend end tidal carbon dioxide (EtCO₂) monitoring, when possible. The patient should be closely monitored for the level of sedation; oversedation can cause respiratory depression, airway obstruction, and loss of airway protective reflexes.

Patients should also be monitored for signs of local anesthetic systemic toxicity (LAST), which is rare but potentially life threatening. Signs of LAST include central nervous system changes (eg, tinnitus, perioral numbness, or seizures) or cardiovascular abnormalities (eg, arrhythmias or cardiac arrest) [15]. If LAST is suspected, further administration of local anesthetic must be stopped and the adverse effects of LAST must be promptly managed (eg, administer lipid emulsion) (table 3). (See "Local anesthetic systemic toxicity", section on 'Management of LAST'.)

Supplemental oxygen — Supplemental oxygen should be continuously administered during ATI [8]. For patients undergoing oral intubation, we prefer to use heated humidified high flow nasal oxygen (HFNO), typically at flows of 15 to 70 L/minutes. Observational studies suggest that HFNO may reduce the incidence of hypoxia during ATI [16,17].

Alternatively, a standard nasal cannula at flows of up to 15 L/minute can provide adequate supplemental oxygenation during ATI in most patients. For patients undergoing nasotracheal awake flexible scope intubation, nasal cannula can still be used by working around the nasal prongs during administration of topical anesthesia and flexible laryngoscopy; the prong in the naris being intubated must be removed prior to inserting the nasotracheal tube.

Airway anesthesia

Choice of technique — Prior to performing ATI, the airway must be anesthetized using topical local anesthetics or a nerve block. We suggest using topical anesthesia with lidocaine rather than other agents or techniques. The lidocaine formulation and application technique are described below. (See 'Topical anesthesia' below.)

Uncommonly, patients are unable to be sufficiently anesthetized with topical anesthesia. In this case, adjunctive nerve block may be useful as follows:

●For awake VL and for patients who have a prominent gag reflex, glossopharyngeal block may be used to provide anesthesia to the posterior third of the tongue and to block the afferent limb of the gag reflex. (See 'Glossopharyngeal nerve block' below.)

●For ATI with nasal approach, sphenopalatine and anterior ethmoidal nerve blocks may be used to anesthetize the nasal cavity, as well as the roof of the mouth, soft palate, and tonsils. (See 'Nerve blocks for nasal cavity' below.)

●For patients with a prominent cough reflex (especially following application of topical local anesthetics), transtracheal block combined with superior laryngeal nerve block may be particularly useful. Together these blocks anesthetize the trachea, the hypopharynx and upper glottis, including the valleculae and the laryngeal surface of the epiglottis. (See 'Trachea (transtracheal injection)' below and 'Superior laryngeal nerve block' below.)

Prior to beginning the intubation procedure, adequacy of anesthesia should be confirmed by testing response to an oral airway or a suction catheter [8].

Topical anesthesia

Oropharynx and larynx — Topical local anesthetics should be applied to the base of the tongue, oropharynx, hypopharynx, and laryngeal structures. We use lidocaine (maximum total 9 mg/kg) because of its rapid onset, high therapeutic index, and availability in a wide variety of preparations and concentrations [10]. Steps include the following:

●We have two approaches to anesthetize the upper airway and suggest using either depending on familiarity and availability of formulations/equipment (eg, atomizer):

•Nebulize 4% lidocaine – We use low oxygen flow rates (2 to 4 L/min) to generate larger particles that will deposit in the oropharynx and upper airway [18].

•Atomized 4% lidocaine combined with topical lidocaine 5% ointment – Using a malleable LTA device, we apply atomized 4% lidocaine to the soft palate, posterior pharynx, tonsillar pillars, pyriform recesses, and glottic opening. After atomization, we apply approximately 2 cm of 5% lidocaine ointment to the back of the tongue using a tongue depressor. The ointment dissolves as it heats up and coats the base of the tongue, vallecula, and epiglottis.

●If performing a flexible scope intubation, we anesthetize the larynx with the "spray-as-you-go" method, which involves intermittently injecting local anesthetic (eg, 4% lidocaine) through the working channel of the flexible intubating scope as it is advanced towards the trachea.

●If performing VL, we anesthetize the larynx by applying local anesthetic with an LTA device.

Nasal passages — When nasal intubation is planned, the nasal passages must be anesthetized in addition to airway anesthesia described above. After administering a topical nasal vasoconstrictor to the nasal passage (described above), we use a nasopharyngeal airway liberally coated with lidocaine 2% mucosal jelly or lidocaine 5% ointment to provide anesthesia and lubrication for passage of the endotracheal tube.

Alternatively, direct application of a combined local anesthetic and vasoconstrictor solution using cotton swabs or cotton pledgets is effective for both anesthesia and vasoconstriction of the nasal mucosa. The choice of the solution used is usually based on availability. Options include lidocaine 2 to 4% with epinephrine, a 3:1 mixture of 4% lidocaine and 1% phenylephrine, or a 1:1 mixture of 4% lidocaine and 0.05% oxymetazoline.

Trachea (transtracheal injection) — The transtracheal block is a form of topical anesthesia of the trachea achieved by percutaneously injecting local anesthetic into the tracheal lumen. As a result of the coughing elicited by the block, the injected local anesthetic is nebulized and provides additional anesthesia of the inferior larynx and vocal cords.

●Equipment – Tuberculin syringe or a 25-gauge needle with lidocaine 1 to 2%; 20-gauge angiocatheter attached to a 5-mL syringe containing 3 mL saline; syringe containing 3 to 5 mL of lidocaine 4% if available. Lidocaine 2% is an effective alternative.

●Positioning – Position the patient supine with the neck in slight extension, if possible. Stand at the side of the patient with the dominant hand closest to the patient.

●Technique – Identify the midline of the cricothyroid membrane as the needle insertion site and raise a small skin wheal with local anesthetic using a tuberculin syringe or a 25-gauge needle. Advance the 20-gauge angiocatheter with the attached saline-filled syringe through the skin perpendicularly while aspirating. When air is freely aspirated, advance the sheath of the angiocatheter, remove the needle, and attach a syringe containing 3 to 5 mL of 4% lidocaine to the catheter sheath that has been left in place. Confirm the sheath position by aspiration of air, warn the patient to expect vigorous coughing, and rapidly inject the local anesthetic during inspiration. The sheath of the angiocatheter may be left in place until the intubation is complete in case more local anesthetic is needed and to decrease the likelihood of subcutaneous emphysema.

Nerve blocks — In addition to topical anesthesia, nerve blocks can be performed to anesthetize the nasopharynx, oropharynx, glottis, and trachea prior to ATI. Glossopharyngeal, sphenopalatine, and anterior ethmoidal nerve blocks are performed topically, whereas the superior laryngeal nerve block is performed with an injection.

Glossopharyngeal nerve block — We usually perform a glossopharyngeal nerve block using the topical method when performing awake intubation with a VL, or for patients with a pronounced gag reflex. This block primarily targets the lingual branch of the glossopharyngeal nerve (cranial nerve [CN] IX), providing anesthesia to the posterior third of the tongue and blocking the afferent limb of the gag reflex. Some blockade of the more proximal branches of CN IX may be achieved, providing anesthesia of the valleculae, the anterior surface of the epiglottis, the posterior and lateral walls of the pharynx, and the tonsillar pillars. This block can also be performed with an injection of lidocaine.

●Positioning – Place the patient in the sitting position and stand facing the patient on the contralateral side of the nerve to be blocked. Instruct the patient to open his/her mouth widely and to protrude the tongue.

●Technique – With the nondominant hand, displace the tongue medially with a tongue blade or a Macintosh 3 laryngoscope blade, forming a gutter or trough along the floor of the mouth between the tongue and the teeth. The gutter ends in a cul-de-sac formed by the base of the palatoglossal arch (also known as the anterior tonsillar pillar), which is a U- or J-shaped structure starting at the soft palate and running along the lateral aspect of the pharynx.

•Topical method – Soak a pledget or cotton tipped applicator in 4% lidocaine. Place and hold the tip at the base of the palatoglossal arch, just lateral to the base of the tongue, for three to five minutes on each side.

•Injection method – Insert a 25-gauge spinal needle 0.25 to 0.5 cm deep at the base of the palatoglossal arch, just lateral to the base of the tongue, and perform an aspiration test. If air is aspirated, the needle has been advanced too deeply (the tip has advanced all the way through the palatoglossal arch) and should be withdrawn until no air can be aspirated; if blood is aspirated, redirect the needle more medially. Inject 2 mL of 1 to 2% lidocaine. Repeat the procedure on the contralateral side.

Superior laryngeal nerve block — This block provides anesthesia of the hypopharynx and upper glottis, including the valleculae and the laryngeal surface of the epiglottis. This block combined with transtracheal injection may be particularly helpful in a patient with a prominent cough reflex. Several different landmarks may be used: the greater cornu of the hyoid bone, the superior cornu of the thyroid cartilage, and the thyroid notch. Use of ultrasound guidance to facilitate this block has been described [19]. We rarely perform these blocks, as adequate anesthesia can usually be achieved with less invasive techniques. It should only be performed by clinicians experienced with this block.

●Equipment – 25-gauge spinal needle attached to a 5-mL syringe containing 1 to 2% lidocaine.

●Techniques – Options include the following:

•Greater cornu of the hyoid bone – Identify the greater cornu of the hyoid and walk a 25-gauge needle off the cornu of the hyoid bone in an anterior-inferior direction. A slight resistance is felt as the needle is advanced through the thyrohyoid membrane, usually at a depth of 1 to 2 cm (2 to 3 mm deep to the hyoid bone). Perform an aspiration test. If air is aspirated, the needle has passed too deep and entered the pharynx; the needle should be withdrawn until no air is aspirated. If blood is aspirated, the needle has cannulated either the superior laryngeal artery or vein or has cannulated the carotid artery; the needle should be directed more anteriorly. When satisfactory needle placement is achieved, inject 2 to 3 mL of 1 to 2% lidocaine as the needle is withdrawn. The block is repeated on the opposite side.

•Superior cornu of the thyroid cartilage – Identify the superior cornu of the thyroid cartilage and walk a 25-gauge needle off in an anterior-superior direction. Perform an aspiration test and inject 2 to 3 mL of 1 to 2% lidocaine. The block is repeated on the opposite side.

•Thyroid notch – In some patients, the easiest landmark to identify may be the thyroid notch. Palpate the thyroid notch and trace the upper border of the thyroid cartilage laterally for approximately 2 cm. Pierce the thyrohyoid ligament with a 25-gauge needle just above the thyroid cartilage at this location and advance the needle in a posterior and cephalad direction to a depth of 1 to 2 cm from the skin. Perform an aspiration test and inject 2 to 3 mL of 1 to 2% lidocaine. Repeat the block on the opposite side.

Nerve blocks for nasal cavity — Some authors of this topic typically perform the sphenopalatine and anterior nerve blocks for awake nasal flexible scope intubation. Both nerves should be blocked for effective analgesia for awake nasal intubation.

●Sphenopalatine nerve block – This block provides anesthesia of the nasal cavity, as well as the roof of the mouth, soft palate, and tonsils.

•Equipment – Long, cotton-tipped applicators or cotton pledgets soaked in either 4% cocaine or 4% lidocaine with epinephrine 1:200,000; bayonet forceps (if using pledgets).

•Technique – Apply the cotton-tipped applicator or pledgets held in forceps along the upper border of the middle turbinate at an approximately 45-degree angle to the hard palate and directed posteriorly until the upper posterior wall of the nasopharynx (sphenoid bone) is reached. The sphenopalatine ganglion underlies the mucosal surface at this point. Hold the applicator or pledgets in place for approximately three to five minutes.

●Anterior ethmoidal nerve block – This block provides anesthesia of the anterior portion of the nasal cavity.

•Equipment – Long, cotton-tipped applicators soaked in either 4% cocaine or 4% lidocaine with epinephrine 1:200,000.

•Technique – Insert the cotton-tipped applicator into the naris parallel to the dorsal surface of the nose until it meets the anterior surface of the cribriform plate. The applicator is held in position for three to five minutes.

SEDATION/ANALGESIA

Goals and complications of sedation — The goals of sedation for awake tracheal intubation (ATI) are to have the patient tolerate the procedure and remain cooperative by providing anxiolysis, amnesia, and analgesia. The decision to use sedation and the sedation plan should be made on a case-by-case basis depending on the indication for the procedure and the patient's ability to cooperate.

Sedation should not be used to compensate for inadequate airway anesthesia. If difficulty is encountered in performing the procedure due to patient coughing, gagging, or discomfort, the adequacy of airway anesthesia should be reassessed and additional topical local anesthetics or an alternative airway anesthesia technique should be used. (See 'Airway anesthesia' above.)

Oversedation may be especially risky in patients with particular concern for aspiration or rapid desaturation. If sedation is deemed necessary, it should be titrated carefully, maintaining adequate respiration, airway reflexes, and cooperation. Oversedation may cause the potentially hazardous scenario of inadequate spontaneous respiration, inability to perform ATI, but presence of airway reflexes that preclude an oral laryngoscopy attempt for airway rescue.

Choice and administration of agent — There are many acceptable sedative regimens, and the choice depends largely on clinician familiarity and location (eg, operating room, emergency department [ED], intensive care unit [ICU]), taking into account patient-specific and situational factors. Opioids, benzodiazepines, alpha-2 agonists, ketamine, or etomidate can be used alone or in combination. The risks, benefits, and dosing of common regimens are discussed briefly here and in more detail separately. (See "Monitored anesthesia care in adults" and "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria".)

●Remifentanil – Benefits include rapid onset, easy titratability, and profound blunting of airway reflexes; its primary disadvantage is respiratory depression. Remifentanil is not readily available in many EDs. It is administered as a continuous infusion (titrated infusion starting at 0.05 to 0.1 mcg/kg/minute) with or without midazolam (0.5 to 1 mg intravenously [IV], repeated as necessary to a total dose of 0.025 to 0.1 mg/kg IV). (See "Monitored anesthesia care in adults", section on 'Opioids' and "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Short-acting opioids (fentanyl, others)'.)

●Dexmedetomidine – This is associated with fewer desaturation episodes compared with opioids with or without midazolam [20]. However, it has a prolonged time to onset of action, is not as rapidly titratable, and can cause hypotension and bradycardia. It is administered as a bolus 0.5 to 1 mcg/kg IV over 10 minutes, followed by a continuous infusion of 0.2 to 0.7 mcg/kg/hour. In the ICU, this is often administered as an infusion without the bolus dose. (See "Monitored anesthesia care in adults", section on 'Dexmedetomidine' and "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Dexmedetomidine'.)

●Ketamine – This agent provides sedation, analgesia, and amnesia while preserving upper airway muscle tone, airway protective reflexes, and spontaneous breathing. In the ED, we administer 25 to 50 mg IV aliquots every 5 to 10 minutes titrated to patient comfort and compliance. In the ICU, ketamine is often given in 10 to 20 mg IV aliquots. (See "Monitored anesthesia care in adults", section on 'Ketamine' and "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Ketamine sedation'.)

●Midazolam and fentanyl – This combination has a narrower therapeutic window compared with the other agents. Doses of midazolam (0.5 to 1 mg IV, repeated as necessary to a total dose of 0.025 to 0.1 mg/kg IV) and fentanyl (25 to 100 mcg IV in divided doses) are administered incrementally. (See "Monitored anesthesia care in adults", section on 'Midazolam' and "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Coadministration of midazolam and fentanyl'.)

PROCEDURE

Flexible scope intubation — For awake flexible scope intubation, the patient is typically placed in the sitting or lateral decubitus position. In the intensive care unit (ICU) or the emergency department (ED), the patient is usually positioned sitting upright to avoid airway obstruction or desaturation. If the patient is in the sitting position, the clinician should stand at the patient's side.

During awake flexible scope intubation, asking the patient to stick out their tongue and phonate can help open the airway and facilitate visualization.

The flexible scope intubation technique is described separately. (See "Flexible scope intubation for anesthesia", section on 'Technique'.)

Video laryngoscopy intubation — We use a hyper-angulated video laryngoscope (VL) instead of a conventional blade (ie, Macintosh-shaped) VL because, in our anecdotal experience, we have found that it causes less pressure on the base of the tongue and a lower incidence of gagging.

The VL intubation technique is described separately. (See "Devices for difficult airway management in adults for emergency medicine and critical care", section on 'Video laryngoscopes'.)

CONFIRMING ENDOTRACHEAL TUBE POSITION — A two-point check must be used to verify the correct placement of an endotracheal tube (ETT). Capnography can confirm ventilation in non-cardiac arrest patients with a sensitivity approaching 100 percent. However, in a spontaneously breathing patient, an ETT placed just above the glottis can also result in a capnographic tracing. Therefore, both tube positioning and ventilation must be confirmed as follows (see "Direct laryngoscopy and endotracheal intubation in adults", section on 'Confirming proper tracheal tube placement' and "Carbon dioxide monitoring (capnography)", section on 'Verification of ETT placement'):

●Visualization

•During flexible scope intubation, after the ETT is in place, tracheal rings should be visualized beyond the tip of the ETT prior to removing the scope.

•During laryngoscopy, the ETT should be seen passing though the vocal cords.

AND

●Capnography – At least seven exhalations with a consistent end-tidal carbon dioxide (ETCO₂) level must be verified to rule out an unrecognized misplaced intubation in the esophagus.

Once a two-point check to confirm successful awake tracheal intubation is completed, general anesthesia can be safely induced or further sedative agents can be safely administered.

MANAGEMENT OF UNSUCCESSFUL OR FAILED INTUBATION — Awake tracheal intubation (ATI) has a very high success rate without major differences between the different techniques, routes of intubation, or specialty of airway operator.

●Unsuccessful intubation attempt – An unsuccessful attempt is defined as an unplanned withdrawal of the flexible intubating scope, laryngoscope, or endotracheal tube (ETT) from the airway [8]. Each subsequent attempt after an unsuccessful attempt should involve a change in the procedure intended to correct/mitigate the presumptive cause of the unsuccessful attempt (eg, alternative device, ETT, and/or airway operator).

●Failed intubation – A failed ATI occurs when three unsuccessful attempts have been performed and, optionally, a fourth and final attempt by a more experienced provider (ie, "3 + 1") has also failed. In this scenario, additional help should be emergently summoned, and 100 percent oxygen should be delivered to the patient. Any sedation should be stopped and reversed, if possible. The approach to the failed airway is presented in algorithms (algorithm 1 and algorithm 3) and discussed separately. (See "Approach to the failed airway in adults for emergency medicine and critical care" and "Management of the failed airway during anesthesia".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Airway management in adults".)

SUMMARY AND RECOMMENDATIONS

●Decision to perform awake tracheal intubation (ATI) – ATI should be considered in a patient with predicted difficulty with airway management; in a patient who would benefit from maintaining spontaneous ventilation, intrinsic airway tone, and/or airway protective reflexes until intubation; and in a patient at risk for cardiovascular decompensation with administration of induction agents (algorithm 1 and algorithm 2). (See 'Decision to perform awake intubation' above and "Management of the difficult airway for general anesthesia in adults", section on 'Awake intubation' and "Approach to the difficult airway in adults for emergency medicine and critical care", section on 'Awake techniques'.)

●Contraindications and precautions – The only absolute contraindication to ATI is patient refusal. We avoid ATI in a patient who requires rapid, immediate intubation, is uncooperative, has a local anesthetic allergy, or has excessive airway bleeding or secretions. (See 'Contraindications and precautions' above.)

●Choosing the approach – The decision to perform ATI with a flexible intubating scope or a video laryngoscope (VL) depends on patient factors, clinician expertise, and availability of equipment. VL is preferred in a patient with active airway bleeding and flexible scope intubation is preferred in a patient with restricted mouth opening. We prefer the oral rather than nasal route for flexible scope intubation unless the patient has trismus or an obstructive lesion of the oral cavity. (See 'Choosing the approach' above.)

●Patient preparation

•Antisialagogues – For patients who undergo ATI, we suggest administering glycopyrrolate (Grade 2C). We administer 0.2 mg intravenously 15 to 30 minutes prior to intubation. This dries airway secretions and may improve visualization. (See 'Antisialagogues' above.)

•Nasal vasoconstrictors – For patients who will undergo nasal ATI as the initial or backup plan should oral intubation fail, we suggest applying a topical nasal vasoconstrictor (Grade 2C)to reduce the risk of bleeding and enlarge the caliber of the nasal passages. Reasonable options are oxymetazoline 0.05% or phenylephrine 0.5%, two sprays to each nostril. (See 'Nasal vasoconstrictors' above.)

•Other measures – These include aspiration prophylaxis for patients at high risk of aspiration (table 2), cardiopulmonary monitoring, and providing supplemental oxygen. (See 'Aspiration prophylaxis' above and 'Monitoring' above and 'Supplemental oxygen' above.)

●Airway anesthesia – The airway must be anesthetized for awake intubation. For patients undergoing ATI, we suggest topical airway anesthesia with lidocaine rather than other agents or forms of anesthesia (Grade 2C). We use nebulized 4% lidocaine with low oxygen flow rates (2 to 4 L/min). A reasonable alternative is atomized 4% lidocaine to the oropharynx and hypopharynx with a malleable laryngotracheal mucosal atomization (LTA) device followed by topical 5% lidocaine ointment applied to the back of the tongue using a tongue depressor. (See 'Topical anesthesia' above.)

If performing a flexible scope intubation, we anesthetize the larynx with the "spray-as-you-go" method. If performing VL, we anesthetize the larynx by applying local anesthetic with an LTA device.

Alternative/adjunct nerve blocks and percutaneous topical anesthesia techniques include the following (see 'Choice of technique' above):

•Transtracheal block (see 'Trachea (transtracheal injection)' above)

•Sphenopalatine and anterior ethmoidal nerve blocks (see 'Nerve blocks for nasal cavity' above)

•Glossopharyngeal nerve block (see 'Glossopharyngeal nerve block' above)

•Superior laryngeal nerve block (see 'Superior laryngeal nerve block' above)

●Sedation – Sedation should not be used to compensate for inadequate airway anesthesia. The sedation plan should be individualized based on the indication for intubation, the patient's ability to cooperate, and clinician familiarity with agents. Options include opioids, benzodiazepines, alpha-2 agonists, ketamine, or etomidate, alone or in combination. (See 'Sedation/analgesia' above and "Monitored anesthesia care in adults", section on 'Drugs used for sedation and analgesia for monitored anesthesia care' and "Procedural sedation in adults in the emergency department: Medication selection, dosing, and discharge criteria", section on 'Medications'.)

●Procedure – Techniques for awake flexible scope intubation and awake VL are similar to those in an unconscious patient, with some minor differences described above. (See 'Procedure' above and "Flexible scope intubation for anesthesia", section on 'Technique' and "Video laryngoscopes and optical stylets for airway management for anesthesia in adults", section on 'Videolaryngoscopy technique'.)

●Confirming endotracheal tube position – A two-point check that includes visualization and capnography must be used to verify the correct placement of an endotracheal tube. (See 'Confirming endotracheal tube position' above.)