Extubation following anesthesia

INTRODUCTION — Extubation at the end of anesthesia may be associated with complications, including loss of the airway and the need to reintubate. It is important to keep in mind that extubation is always elective, and should be performed only when physiologic, pharmacologic, and contextual conditions are optimal. Similar to the requirement for a strategy when planning intubation, a specific individualized plan for extubation should be created, beginning with risk stratification.

The topic will review risk stratification for extubation, and strategies for extubations based on predicted risk. Other aspects of airway management for anesthesia are discussed separately. (See "Management of the difficult airway for general anesthesia in adults" and "Airway management for induction of general anesthesia".)

COMPLICATIONS OF EXTUBATION — Complications can be classified as (table 1):

●Physiologic effects of extubation

●Inability to tolerate extubation (resulting in the need for reintubation)

●Difficulty re-establishing the airway

Physiologic effects of extubation — Extubation of the trachea during emergence from anesthesia can cause arterial and venous hypertension, tachycardia, coughing or bucking, and agitation [1-3]. Coughing, bucking, breathholding and straining during extubation also cause increases in intracranial [4] and intraocular pressure. Most healthy patients will tolerate these transient physiologic effects, but certain patients are at greater risk of serious consequence. Examples include patients with significant cardiac or cerebrovascular disease, preexisting raised intracranial or intraocular pressure, patients who undergo neck surgery, neurosurgery, and some plastic or ocular surgical procedures. (See 'Minimizing physiologic response to extubation' below.)

Inability to tolerate extubation — The inability to tolerate extubation can be caused by the following, with listed causes:

●Airway obstruction – Inadequate airway patency due to macroglossia, laryngeal edema, laryngospasm, vocal cord paralysis, tracheomalacia, intrinsic laryngeal or tracheal obstruction (eg, from a "coroner's clot" or ball valve lesion), or extrinsic airway compression; obtundation due to residual analgesic or anesthetic medications.

●Inadequate ventilation – Neuromuscular weakness due to preexisting disease (eg, chronic lung disease) or residual neuromuscular blockade; opioid, sedative, or anesthesia induced respiratory depression; splinting due to pain.

●Inadequate oxygenation – Atelectasis, reduced functional residual capacity or increased oxygen (O₂) consumption.

●Inadequate clearance of secretions – Reduced level of consciousness, impaired cough, increased respiratory secretions or inspissation of secretions.

●Inability to protect the airway resulting in aspiration of gastric contents – Diminished neuromuscular strength or coordination, reduced level of consciousness, airway swelling or impaired gastric emptying.

Many of these factors may simply be a function of timing. For example, incomplete reversal of neuromuscular blockade or persistence of respiratory depression from opioids or volatile anesthetics may result in complications, which could be avoided with improved timing of extubation.

Difficulty re-establishing an airway — Difficulty re-establishing an airway may relate to anatomic, physiologic, or contextual challenges.

●Anatomic challenges – The anatomic risk factors for difficulty with airway management are well established, though they generally have only moderate sensitivity and specificity (table 2 and table 3 and table 4 and table 5). When considering reintubation, anatomical challenges may relate to the reasons why initial intubation was difficult, or changes that have occurred since that initial intubation. Initial intubation may have provided a poor laryngeal view, required multiple attempts or laryngoscopists, or involved an advanced technique such as an awake intubation. An easy intubation accomplished under controlled elective conditions does not assure that an emergency reintubation will be equally easy, but a difficult initial intubation will almost certainly be more difficult under emergency conditions.

During emergency reintubation, the view of the airway may be compromised by blood, secretions, or stomach contents, airway trauma, or swelling. There may also be limited or suboptimal access to the airway if the cervical spine is unstable or immobilized, the jaws are clenched or wired shut, or other factors have changed. After tracheal resection, cervical extension may be deliberately restricted by a "guardian suture" between the chin and sternum.

●Physiological challenges – Physiological abnormalities at the time of emergency reintubation may render patients less tolerant of delays and persistent or prolonged intubation attempts. Patients may be hypoxic, hypercapnic, acidotic or hemodynamically unstable.

●Contextual challenges – The emergency nature of a reintubation may result in insufficient information, medication, equipment, qualified personnel, suitable positioning, or access to the airway. Other human factors such as operator fatigue, situation awareness, stress, and urgency may interfere with an organized, appropriate, and well-executed approach to managing the airway [5,6].

INCIDENCE OF EXTUBATION COMPLICATIONS — The true incidence of extubation associated complications is unknown and may be under-reported in the literature. The physiological complications described above are rarely reported as extubation failures. In addition, although reintubation is more clearly seen as a complication of extubation, there is no consensus on the length of time between extubation and the need for reintubation that would define failed extubation.

Minor complications are common following extubation; major complications are rare but these can be catastrophic. Examples of studies on the incidence of extubation complications include the following:

●The 4^th National Audit Project (NAP4) in the United Kingdom found that major airway complications following extubation were responsible for approximately one-third of the reported cases relating to anesthesia, and all reported complications during emergence or recovery were due to airway obstruction [7]. Of the 38 reported cases during emergence or recovery, hypoxia due to airway obstruction resulted in cardiac arrest in five patients, two of whom died. Prolonged hypoxia occurred in approximately one-half, and a surgical airway was attempted in 10 patients.

●The American Society of Anesthesiologists Closed Claims Project, which analyzed claims between 1984 and 1999, reported that adverse respiratory events leading to death and brain injury were more common among claims relating to extubation than intubation [8]. Of those claims relating to extubation, 83 percent resulted in death or brain damage [8]. A review comparing closed claims between 1993 and 1999 and 2000 and 2012 found no improvement in the incidence of failed extubation or severity of outcomes, in contrast with the improvements seen in intubation related injury [9].

●In a single institution retrospective review of over 100,000 adult general anesthetics, 0.1 percent of patients required reintubation in the PACU [10]. The need for reintubation was more commonly due to hypoxemic or hypercapnic respiratory insufficiency, with approximately 20 percent due to upper respiratory obstruction, although the rate of obstruction was higher in the NAP4 study [11].

Inability to tolerate extubation is more common following certain procedures, such as otolaryngologic panendoscopy [12] and also more common following mechanical ventilation in the intensive care unit. Reintubation is required within 48 to 72 hours in up to 14 percent of such patients (see "Extubation management in the adult intensive care unit", section on 'Postextubation management').

Non-invasive support such as high-flow nasal oxygen may reduce postoperative pulmonary complications including the need for reintubation in high-risk patients or those undergoing high-risk procedures [13]. (See "Respiratory problems in the post-anesthesia care unit (PACU)", section on 'Ventilatory support'.)

EXTUBATION RISK STRATIFICATION — For each patient intubated for anesthesia, an extubation strategy should be created, starting with a risk assessment. The outcome of this risk assessment will allow a tailored extubation strategy. The algorithms in the Difficult Airway Society Guidelines for the management of tracheal extubation incorporate a more dichotomous estimate of risk (low versus "at risk") (algorithm 1A-C) [14]. The American Society of Anesthesiologists Task Force Practice guidelines [15], the Canadian Airway Focus Group Airway Management guidelines [16], and the French Society of Anesthesiologists [17] have also published recommendations on the management of extubation of the difficult airway, all of which stress the principles of planning and risk assessment. Risk stratification involves estimation of the following, which may occur together:

●The likelihood that the patient will not tolerate extubation

●The predicted difficulty with reintubation, if it is required, because of preexisting difficulty with airway management, changes that have occurred during the surgical procedure, or the clinical context at the time of reintubation

Low-risk extubations are those in which both the predicted risk of intolerance of extubation and the predicted risk of difficulty with reintubation are low.

The risk assessment should be completed prior to intubation, as the resulting strategy for extubation may then affect choices made at the time of intubation. For example, if it is anticipated that the strategy may involve deferring extubation at the end of the procedure, it will be prudent to choose a tracheal tube that can be safely left in-situ in the intensive care unit. If the anticipated strategy involves the use of an AEC, a discussion with the patient regarding this prior to the induction of anesthesia, may help improve tolerance of the AEC following extubation. This risk assessment should be repeated prior to considering extubation, to allow for factors that have changed during the procedure.

Risk factors for extubation failure — A number of patient and surgical factors may contribute to the inability to tolerate extubation, including (table 1):

●Obesity – Patients with obesity may fail extubation because of difficulty with oxygenation, ventilation, or airway obstruction. This may be attributable to increased supraglottic adipose tissue, obstructive sleep apnea (OSA), or central hypoventilation syndrome. Subsequent management of their extubation failure may also be problematic; both face mask ventilation and reintubation may be more difficult than in patients of normal weight. Obesity or associated physical features are risk factors for difficulty with all forms of airway management (table 2 and table 3 and table 5). (See "Anesthesia for the patient with obesity", section on 'Airway management'.)

Patients with obesity were disproportionately represented in the Fourth National Audit Project of the Royal College of Anaesthetists and Difficult Airway Society (NAP4) serious adverse airway outcomes study [7].

●Obstructive sleep apnea – Patients with OSA are more likely to require emergent reintubation after surgery [18]. (See "Surgical risk and the preoperative evaluation and management of adults with obstructive sleep apnea", section on 'Respiratory complications'.)

●Parkinson disease – Patients with Parkinson disease and multiple system atrophy may have dysphonia or hypophonia and are susceptible to abnormal vocal cord closure, including rigidity or excessive laxity [19,20]. These abnormalities may rarely be associated with airway obstruction [21]. There are reported cases of postoperative airway obstruction requiring reintubation in patients with Parkinson disease, particularly in those from whom their antiparkinsonian medications were withheld for surgery [22,23].

●Rheumatoid arthritis – Rheumatoid arthritis commonly involves the cricoarytenoid and cricothyroid joints with pannus or fibrosis, in addition to the more commonly recognized problems affecting their cervical spines and temporomandibular joints. (See "Clinical manifestations of rheumatoid arthritis", section on 'Cricoarytenoid joint' and "Clinical manifestations of rheumatoid arthritis", section on 'Extraarticular involvement' and "Cervical subluxation in rheumatoid arthritis".)

These patients are more prone to airway obstruction and reintubation may be complicated by cervical instability [24].

●Paradoxical vocal fold motion – Airway obstruction after extubation may be a consequence of a condition known as paradoxical vocal fold motion, frequently misdiagnosed as recurrent laryngospasm or refractory asthma [25,26]. (See "Inducible laryngeal obstruction (paradoxical vocal fold motion)".)

This disorder does not confer any special difficulty with respect to intubation, but these patients are difficult to extubate, due to the much higher risk of airway obstruction. The safest method of managing their extubation has not been studied, but it probably involves extubating in the least stimulating manner. Deep extubation is one reasonable option if there are no contraindications, or by substituting a tracheal tube for a supraglottic airway (SGA) under deep anesthesia (see 'Bailey maneuver' below). Both deep extubation, and substitution for a supraglottic airway should only be performed in the absence of other factors contributing to a higher risk extubation, when a more conservative strategy should be chosen.

●High risk surgical procedures – Several surgical procedures on the neck, including thyroidectomy, carotid endarterectomy, and anterior cervical spine surgery may result in an increased risk of extubation failure. This may be due to one or more of postoperative bleeding, lymphatic disruption causing edema, neurologic injuries affecting vocal cord motion, dynamic airway collapse, or airway compression above, below, or at the level of the larynx.

MANAGEMENT OF EXTUBATION — Extubation should be considered an elective procedure, which should be planned in advance and executed when conditions are optimal. After risk stratification (including both the risk of tolerating extubation, and the predicted difficulty with reintubation), an individualized plan should be followed, designed to minimize complications and eliminate preventable reintubations.

Minimizing physiologic response to extubation — A number of techniques have been used to prevent or reduce some of the physiologic responses to extubation, principally suppression of severe cough, hypertension, tachycardia, breath-holding and laryngospasm. Strategies include the administration of lidocaine, opioids, dexmedetomidine [27], or esmolol; a "no-touch" technique; deep extubation; and use of the Bailey maneuver (ie, substitution of a supraglottic airway [SGA] for the endotracheal tube [ETT]). (See 'Deep extubation' below and 'Bailey maneuver' below.)

●Lidocaine – Lidocaine may be administered topically, intravenously, or using the ETT cuff as a drug delivery system. Topical and intravenous (IV) lidocaine work the fastest but if given at the time of intubation, may no longer be active (unless re-dosed [27-29]) when extubation is performed. Alkalinized and nonalkalinized [30] lidocaine diffuses out of the ETT cuff, resulting in improved ETT tolerance and reduced cough, agitation, and hemodynamic changes during extubation [30]. However, in a network meta-analysis of medications used to reduce emergence coughing after anesthesia, intracuff lidocaine was associated with delayed extubation times compared with placebo and with the other medications studied [27].

●Opioids – Low-dose opioids may also suppress the cough and hemodynamic response to tracheal extubation. Opioid regimens for this purpose must balance the desired antitussive effect with potential for excessive sedation and respiratory depression. Remifentanil is probably the best suited opioid for this purpose because of its ultrashort duration of action, though alfentanil, fentanyl, and morphine have all been used. The beneficial effect of remifentanil was reported in a trial that included 70 female patients who underwent thyroidectomy and were randomly assigned to receive a bolus of lidocaine (1.5 mg/kg) or continuation of low dose remifentanil by target controlled infusion (effect site concentration 2.0 ng/mL) at the end of surgery [28]. Patients in the remifentanil group had a lower incidence of cough (20.6 versus 72.7 percent), and lower mean arterial pressure and heart rate, compared with patients who received lidocaine, with no difference in time to emergence, sedation, or respiratory rate.

●Dexmedetomidine – Dexmedetomidine administered by infusion or by bolus administration has been reported to attenuate the hemodynamic response to extubation and emergence from anesthesia [31-33], and may also reduce the incidence of severe cough [27]. Dexmedetomidine produces dose-dependent decreases in heart rate and blood pressure, and can cause hypotension and bradycardia. However, in one small study a low bolus dose of 0.5 mcg/kg administered over 60 seconds, five minutes prior to the end of surgery, reduced cough and modestly reduced systolic blood pressure and heart rate, compared with patients who received saline [31]. Bradycardia occurred in 1 and hypotension in 3 of 30 patients who received dexmedetomidine.

A network meta-analysis and systematic review of randomized controlled trials comparing multiple drug regimens among adult patients found that remifentanil, dexmedetomidine, and fentanyl were the most successful approaches to the suppression of severe cough upon emergence [27].

●Antihypertensive/antiarrhythmic medications – A variety of antihypertensives or antiarrhythmic drugs have been used to attenuate the hemodynamic responses to extubation. Short-acting agents may be preferred in order to avoid postextubation hypotension. Options include calcium channel blockers (eg, clevidipine 1 mg/hour IV, nicardipine 100 to 500 mcg IV) and beta blockers (eg, esmolol 1.5 to 2 mg/kg IV [1,34,35], labetalol 5 to 20 mg IV [36], metoprolol 1 to 5 mg IV [37]).

●No-touch technique – The "no-touch" technique involves extubation without patient stimulation, performed in a quiet atmosphere. Small studies in children [38] and adults [38] suggest that a no touch technique may be associated with a low incidence of cough and laryngospasm.

For this type of extubation, after ensuring adequate reversal of neuromuscular block, the pharynx is carefully suctioned while the patient is still deeply anesthetized. As the level of anesthesia lightens, spontaneous ventilation is established, and the patient is allowed to waken without any form of stimulation, including that which typically occurs around the time of emergence (eg, patient transfer from operating table to the bed, removing tape and adhesive pads, suctioning through the endotracheal tube). Extubation is performed once the patient responds to their name and opens the eyes and mouth on request, assuming other criteria are satisfied.

Low-risk extubation techniques — Low-risk extubations are those in which both the predicted risk of intolerance of extubation and the predicted risk of difficulty with reintubation are low. During emergence from anesthesia, patients should be extubated when either deeply asleep or when awake and appropriately responsive to instructions, not between these two states. Most adults are extubated awake.

Awake extubation — A routine extubation will usually be performed with the patient awake, to allow return of respiratory drive, airway tone, and protective airway reflexes. A typical sequence for routine awake extubation is as follows (algorithm 1B) [14]:

●Oxygenate – Re-oxygenate for several minutes with a high-inspired oxygen concentration with or without continuous positive airway pressure (CPAP) prior to extubation. This increases the oxygen storage in the functional residual capacity to increase the margin of safety in case of apnea, hypopnea or airway obstruction during or following extubation. Short-term exposure to a high fraction of inspired oxygen (FiO₂) may increase atelectasis, partially offset by the use of positive end-expiratory pressure (PEEP) [39], pressure support [40], or a vital capacity recruitment maneuver prior to extubation [41]. The relative risks of atelectasis versus post-extubation hypoxemia from other causes must be assessed by the clinician.

●Position optimally – Place the patient in a position that optimizes spontaneous ventilation and also allows access to the airway for mask ventilation. This will generally approximate a ramped position, particularly for patients with obesity, and may require a standing platform for the clinician to access the patient's face.

●Optimize environment – Confirm availability of support, monitoring, and airway management equipment, in case reintubation is required.

●Optimize the patient – Confirm the following:

•Reversal of neuromuscular blockade (ie, train of four ratio >0.9). (See "Monitoring neuromuscular blockade".)

•Adequate analgesia.

•Adequate spontaneous ventilation: evaluate the frequency, regularity, and depth of spontaneous breathing, spirometry and end-tidal carbon dioxide (CO₂).

•Oxygen saturation compatible with face mask supplementation.

It is important to be confident that the oxygen (O₂) saturation can be adequately maintained after removal of the respiratory support. Patients dependent upon high-FiO₂ and PEEP/CPAP will either require postoperative non-invasive ventilatory support, CPAP with a tight-fitting face mask, high flow nasal oxygen [42], or a Boussignac CPAP valve [43]. If the post-anesthesia care unit (PACU) resources are insufficient to provide this level of care, it is probably best to defer extubation.

•No further noxious stimulus expected.

•Recovery of consciousness with purposeful response to simple instructions.

●Clear secretions – Ensure that drapes are removed, the pharynx can be visualized, assessed, and secretions suctioned as appropriate. Suction the pharynx carefully; avoid causing trauma or inducing a gag reflex.

If nasotracheal intubation had been performed, blood can pool and coagulate in the nasopharynx, concealed behind the nasotracheal tube. When the nasotracheal tube is removed, the clot can be inhaled resulting in airway obstruction ("coroner's clot") [7]. Careful inspection of the nasopharynx may be difficult but inspection should be attempted under deep anesthesia, by partial retraction of the soft palate and gentle suctioning behind the nasotracheal tube. Consider the insertion of a suction catheter during the withdrawal of the tube from the nose.

●Insert bite block – Insert a bite block (eg, rolled gauze or firm foam affixed to the face to ensure that it is not aspirated) after suctioning the pharynx, to prevent occlusion of the ETT if the patient bites down on the tube during emergence. A strong inspiratory effort against an occluded tracheal tube can result in negative pressure pulmonary edema (also known as post-obstructive pulmonary edema). Remove the bite block along with the ETT to avoid airway obstruction.

●Recruitment breath versus trailing suction – Extubation following a recruitment maneuver or at peak inspiration has been advocated to limit atelectasis. In addition, a positive pressure breath may help expel secretions and reduce the risk of laryngospasm. Alternatively, the suction technique may be used, whereby secretions are removed by applying suction via a suction catheter placed in the ETT during extubation. In young children, the suction technique may cause more rapid O₂ desaturation than pre-extubation administration of a single inflation with 100 percent O₂ [44]. In contrast, in one study that compared these two techniques in adults with BMI <30 kg/m² after general anesthesia, there was no difference in the time to desaturation to SpO₂ <92 percent, the frequency of desaturation, or the need for supplemental O₂ at one hour after extubation [45].

●Deflate ETT cuff fully and remove ETT

●Administer O₂ by face mask – Application of the anesthesia face mask with the breathing circuit allows administration of 100 percent O₂, and assessment of tidal volume.

●Observe – Continue monitoring and close observation of vital signs and ventilation while preparing for transport.

●Position – Position the patient head up for transport to the PACU.

●Provide supplemental O₂ – Continue supplemental oxygen during transport to the PACU.

Deep extubation — Deep extubation may be performed to reduce emergence phenomena such as coughing, straining, laryngospasm, and hemodynamic stress [46]. However, extubation prior to recovery of protective laryngotracheal and upper airway reflexes and upper airway tone may increase the risks of aspiration and airway obstruction. Thus, deep extubation should not be performed for patients in whom mask ventilation or reintubation is anticipated to be difficult, nor for patients who are at increased risk of aspiration.

The Difficult Airway Society extubation guidelines refer to deep extubation as an advanced technique that should be reserved for low-risk patients [14].

Deep extubation should not be performed until painful or other noxious stimuli have ended. A high FiO₂ is provided. Muscle relaxation is reversed, and adequate spontaneous ventilation is established. The pharynx is suctioned, the tracheal tube cuff is deflated, and the tracheal tube removed while anesthesia is maintained at a depth sufficient to avoid coughing or a change in breathing pattern. Oxygen is provided by a face mask with simple airway maneuvers as required to maintain patency [14].

Bailey maneuver — The Bailey maneuver (substitution of an ETT with an SGA while the patient is still deeply anesthetized), is an alternative method of deep extubation that maintains airway control, if successful. This technique may be beneficial in patients who are more susceptible to airway reactivity, as an SGA is generally better tolerated than an ETT during emergence from anesthesia. However, a failed technique could convert a controlled airway to a lost airway. This technique requires practice in non-critical airways and has been considered an advanced extubation technique [14,47].

Efficacy of the Bailey maneuver was evaluated in a small study in which 66 anesthetized patients were randomly assigned to extubation awake, extubation while deeply anesthetized, or extubated after insertion of a laryngeal mask airway while deeply anesthetized and paralyzed with neuromuscular blocking agents [48]. Airway obstruction occurred in 17 of 22 patients who were extubated deep, and the lowest incidence of airway complications occurred in the patients who had LMAs inserted.

Properly executed [49], this technique offers other advantages. After reversal of neuromuscular blockade, a well-seated SGA allows the resumption (and assessment) of spontaneous ventilation with a controlled depth of anesthesia and supplemental O₂. It sequesters secretions away from the larynx, providing an unimpeded view of the glottic and subglottic anatomy and function using a flexible endoscope [50]. This may be particularly useful in patients with suspected paradoxical vocal cord motion, laryngeal nerve dysfunction or tracheomalacia [51].

Higher-risk extubation — Higher risk extubations are those in which either the predicted risk of intolerance of extubation OR the predicted risk of difficulty with reintubation are elevated. The risk is highest if both factors are present.

Extubation should be postponed if the risk of failure can be reduced by doing so. This risk reduction might be due to anatomical factors (ie, reduction in airway swelling) physiological factors (improved respiratory reserve or hemodynamic stability) or contextual factors (optimized time of day, location or personnel). If the decision to postpone extubation results in a transfer of this responsibility to someone else, clear communication is of the utmost importance, particularly if the airway management had been difficult.

High risk extubation procedure — Once the decision is made to extubate, the procedure described for low-risk extubation may be modified by using techniques that confirm the patient's probable ability to tolerate extubation, and facilitate reintubation should it prove necessary, as follows.

Cuff-leak test — This test has been used to assess the adequacy of airflow around the tracheal tube and is used for patients who are at risk for airway edema (eg, patients with significantly positive fluid balance, prolonged Trendelenburg or prone positioning, maxillofacial or neck surgery). Qualitative and quantitative versions of this test have been evaluated [52] and despite limited predictive value, it has been recommended in patients at risk of post-extubation stridor [53]. After suctioning the pharynx, the cuff is slowly deflated and the tracheal tube is progressively occluded. A spontaneously breathing patient should be able to breathe in and out around the tube. To the extent that this cannot be accomplished, it may reflect either insufficient respiratory power or airway swelling. However, presence of a leak does not rule out the possibility of subsequent airway obstruction or extubation failure of a nonobstructive cause.

●If a cuff leak is detected in patients without other risk factors for failed extubation (eg, inadequate oxygenation or ventilation, predictors of difficult airway management, impaired protective airway reflexes), extubation may be performed with careful postextubation observation.

●If there is no leak around a deflated ETT cuff and if the absence of leak is presumed to be due to swelling or other factors that are likely to resolve over time, we typically delay extubation until conditions improve. (See 'Airway exchange catheters' below and 'Elective surgical tracheostomy' below.)

Airway exchange catheters — Most airway guidelines recommend the use of an AEC when extubating a patient with a difficult airway [14-17,47]. We use an AEC as part of an extubation strategy for higher risk extubations to assist with reintubation, should that be required. The device is inserted through the ETT and left in place with the tip in the trachea after extubation. If reintubation is necessary, the ETT is reinserted over the AEC.

When properly inserted and secured, AECs are generally well-tolerated without a need for sedation or topical anesthesia. Patients can generally talk, cough, and breathe around the device. Intolerance most often indicates that the catheter has been advanced too deeply or has not been adequately secured in the midline of the mouth.

Efficacy — AECs have a high success rate when used to guide reintubation. In a retrospective review of 354 patients with difficult airways who had an AEC left in situ after extubation, 51 patients required reintubation while the AEC was in place, and 36 required reintubation after the AEC was removed [54]. Of those with the AEC in situ, 47 of 51 patients were successfully reintubated, 87 percent on the first attempt, compared with a 14 percent first-attempt success without the AEC. Those reintubated with the AEC were also less likely to experience SpO₂ <70 percent, heart rate <40, three or more attempts at intubation, esophageal intubation, or require a rescue airway technique. This study was carried out in an intensive care unit (ICU; with an attending anesthesiologist managing or supervising the management). Importantly, only 41 percent of the reintubations occurred within the first two hours, suggesting that, at least in the ICU, AECs are frequently removed prematurely. There were failures with this technique, most occurring as a result of the inadvertent withdrawal of the catheter during the attempted reintubation.

The success rate of reintubation over an AEC can be further improved using indirect (video) laryngoscopy. In a retrospective study including 51 intubated patients who required reintubation and had no view of the glottis with direct laryngoscopy, indirect laryngoscopy was attempted to visualize reintubation over an AEC [55]. First attempt success was reported in 47 of the 49 patients (96 percent). Videolaryngoscopy facilitated correct manipulations while avoiding arytenoid, vocal cord, and commissural impingement or inadvertent buckling of the AEC.

Devices — The most commonly used AEC is the Cook AEC, which is available with outer diameters (OD) of 8, 11, 14 and 19 Fr. These are intended for exchange of ETT with inner diameters (ID) of at least 3, 4, 5 and 7 mm, respectively (picture 1). The AEC has distal end and side holes and a proximal connector that allows administration of O₂. A specialized, longer device with an extra firm shaft and soft tip is available for exchange of double-lumen tubes [56].

The Cook AEC was licensed for use as an exchange catheter and not intended to remain in situ for use should reintubation be required [57]. Nonetheless, it is widely used ("off-label") as insurance in the event of such a need [58]. The Staged Extubation Set is marketed for the exchange of an SGA or tracheal tube, though it is not licensed in the United States for delayed reintubation (picture 2). This set consists of an Amplatz guidewire (outer diameter of 0.038 inch, length of 160 cm) that can be passed through and appropriately positioned via the working channel of a flexible intubating scope (FIS) or more simply, aligned with the depth markings on the tracheal tube about to be removed. The guidewire can be secured in situ. If reintubation is required, a 14 Fr tapered AEC is passed over the guidewire and the new tracheal tube (ID >5 mm) is advanced over the AEC. There is limited literature on this device and what has been published is not very reassuring [59-61]. [62]

Leaving an AEC in the trachea is an "off-label" application of these devices, but is supported by expert opinion [62] and several professional societies when used as described [14,15].

AEC technique — The technique for using an airway exchange catheter (AEC) during extubation is as follows:

●Initial steps for extubation are the same as those used for routine extubation above (ie, preoxygenate, optimize the patient and environment, clear secretions, insert bite block). (See 'Low-risk extubation techniques' above.)

•Just prior to extubation, insert the AEC into the existing orotracheal or nasotracheal tube, ensuring that the depth markings of the ETT and AEC are aligned.

•Deflate the ETT cuff slowly to minimize coughing.

•Remove the ETT and confirm that the depth of the AEC has not changed.

•Secure the AEC. For oral placement, a four-point fixation of the AEC in the midline can be used (figure 1).

•If supplemental oxygen is required, this should be administered by face mask, and NOT via the AEC. The AEC can be passed through a slit created in a face mask (figure 1).

●If reintubation is required over the AEC, select the best sized ETT such that the outer diameter of the AEC and the internal diameter of the ETT are closely matched, to avoid difficulty passing the ETT. A gap between the AEC and the ETT can create a lip of ETT that may impinge on the arytenoids or vocal cords as the ETT is passed. The suggested technique is as follows:

•Use indirect (video) laryngoscopy (if possible), retracting the tongue and visualizing the glottis.

•Advance the new ETT over the AEC, rotating as required, and inflate ETT cuff.

•Remove the AEC.

•Confirm intubation with capnography and auscultation of bilateral breath sounds.

●Administration of supplemental O₂ through AEC – Oxygen insufflation through an AEC should be avoided. If necessary, should be performed with extreme caution, and should never be used in the presence of complete airway obstruction. Oxygen insufflation should be considered only in the presence of significant hypoxia and when reintubation is delayed. If oxygen desaturation occurs with an AEC in situ, the preferred approach should be to reintubate over the AEC.

Although AECs are hollow and have connectors to permit positive pressure and jet ventilation, these techniques may cause barotrauma [63] and have resulted in major morbidity and death [64].Even low flow oxygen insufflation (eg 1 to 2L/minute) may result in harm, especially when used in the presence of airway obstruction [65,66].

ELECTIVE SURGICAL TRACHEOSTOMY — In some circumstances, it may be unsafe to remove a tracheal tube even if this is postponed for hours or days. This may be a consequence of a bulky intraoral flap, an obstructing or otherwise tenuous airway, significant swelling, or bleeding in or around the airway. If significant short-term improvements are not anticipated in a patient with a critical airway, an elective tracheostomy should be considered when planning extubation. Such a decision should take into account the likely chance of success in securing a compromised airway on an emergency basis. An elective tracheostomy may be safer choice than a prolonged attempt or multiple attempts to re-establish an airway. (See "Tracheostomy: Rationale, indications, and contraindications".)

CONSERVATIVE STRATEGIES AFTER EXTUBATION — When patients develop respiratory complications following extubation, several strategies may be used to avoid reintubation for patients who do not require urgent reintubation. In addition to head-up positioning and high concentration supplemental oxygen (O₂), continuous positive airway pressure (CPAP) is easily applied in the operating room after extubation. Other strategies that may be considered include high flow nasal O₂ [42,67], nebulized epinephrine, diuretics, and administration of inhaled O₂/helium mixture, depending on the etiology of respiratory compromise.

These and other strategies and the approach respiratory insufficiency after anesthesia are reviewed separately. (See "Respiratory problems in the post-anesthesia care unit (PACU)".)

AIRWAY MANAGEMENT FOR PATIENTS WITH COVID-19 — In patients with novel coronavirus disease 2019 (COVID-19 or nCoV), there is a high risk of aerosol spread of the virus during airway management, including during extubation. Extubation may represent a higher risk for aerosol spread than intubation/initial airway management [68]; therefore, some of the techniques discussed for management of extubation may not be appropriate in patients who are infected with airborne pathogens, due to the risk to staff. This and other issues related to airway management in patients with COVID-19 are discussed separately. (See "Overview of infection control during anesthetic care", section on 'Infectious agents transmitted by aerosol (eg, COVID-19)'.)

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" and "Society guideline links: COVID-19 – Index of guideline topics".)

SUMMARY AND RECOMMENDATIONS

●Extubation strategy – For each patient intubated for anesthesia, a strategy should be created for safe extubation, starting with an estimate of the degree of risk. This strategy should be created at the time of intubation, as it may affect the choice of tracheal tube, route of insertion of the tracheal tube (oral vs nasal) and the discussion with the patient prior to induction of Anesthesia. The plan may be revised due to changes that occur during the surgical procedure (algorithm 1A). (See 'Extubation risk stratification' above.)

●Risk stratification – Extubation risk stratification should include the likelihood that the patient will not tolerate extubation, requiring reintubation, and the likelihood that reintubation would be difficult if it becomes necessary (eg, due to anatomic, physiologic, or contextual challenges) (algorithm 1C and table 1). (See 'Extubation risk stratification' above.)

Low risk extubations are those in which both the predicted risk of intolerance of extubation and the predicted risk of difficulty with reintubation are low (algorithm 1B). (See 'Low-risk extubation techniques' above.)

●Awake versus deep extubation – Most adults are extubated awake (see 'Awake extubation' above). Deep extubation may be performed for low-risk extubations to avoid coughing, straining, laryngospasm, or hemodynamic stress, in patients without risk factors for difficult mask ventilation or aspiration. (See 'Deep extubation' above.)

●Optimization prior to extubation

•Patients at higher risk of extubation failure should be reassessed prior to extubation for optimization of cardiovascular, respiratory, metabolic, and neuromuscular status; extubation should be postponed if the risk of failure can be reduced by doing so (algorithm 1C). (See 'Higher-risk extubation' above.)

•Extubation can cause physiological effects, including hypertension, tachycardia, coughing or bucking, and increases in intracranial and intraocular pressures. Strategies to avoid these effects include administration of lidocaine, opioids, or beta blockers, and deep or "no-touch," extubation. (See 'Minimizing physiologic response to extubation' above.)

●Use of airway exchange catheter (AEC) – The decision to use an AEC should be based on the perceived risk of difficulty with reintubation. For the patient with a higher risk extubation due to potential difficulty with reintubation, in whom no further benefit will be derived from deferring extubation, we use an airway exchange catheter (AEC). The AEC is left in place with the tip in the trachea and can be used to guide reinsertion of an endotracheal tube (ETT) over the AEC (figure 1). (See 'Airway exchange catheters' above.)

●Elective tracheostomy – Elective tracheostomy may be performed rather than extubation for patients who will require prolonged intubation or who are likely to have a persistent risk of airway obstruction. (See 'Elective surgical tracheostomy' above.)