Secondary Logo

Journal Logo

Tracheal Extubation of Patients With Cervical Spine Injury: A Case Report and Review of Literature

Nowicka, Aleksandra MD; Ungureanu, Narcis MD; Balasubramanian, Shyam MD; Mendonca, Cyprian MD

doi: 10.1213/XAA.0000000000000410
Case Reports: Case Report

In patients with cervical spine injuries, emergence from anesthesia and tracheal extubation can prove as challenging to the anesthesiologist as the tracheal intubation. We report a case of a patient with a potentially unstable cervical spine injury who presented for a nonspinal surgery and experienced agitation on emergence from anesthesia. The use of an intravenous sedative was necessary to ensure cervical spine immobilization but was complicated by severe respiratory depression and the need for reintubation and admission to intensive care. The case report is followed by a review of literature relating to safe extubation of patients with cervical spine injuries. Possible complications during emergence and various methods to prevent these complications are discussed.

From the Department of Anaesthesia, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, United Kingdom.

Accepted for publication July 7, 2016.

Funding: None.

The authors declare no conflicts of interest.

Address correspondence to Aleksandra Nowicka, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK. Address e-mail to

The 4th National Audit Project of the Royal College of Anesthetists and Difficult Airway Society (NAP4) revealed that 28% of the total airway complications occur at emergence or in the recovery period.1 This phase of anesthesia can be particularly challenging in patients with cervical spine instability. Immobilization of the neck during airway maneuvers to prevent neurologic deterioration is accepted widely as a standard of care in these patients;2 however, its maintenance during emergence from anesthesia may be difficult. Prevention of airway complications is also crucial in these cases. Although tracheal reintubation after extubation in theatres is rare and quoted at 0.1% to 0.45% in a recent publication,3 in this particular group of patients, it may be difficult to perform.

The clinical case, which we have recently encountered, illustrates some of the challenges an anesthetist may face during the time of patient’s emergence. This serves as a starting point for discussion on planning and performance of tracheal extubation in a cohort of patients with cervical spine injury.

The patient has reviewed the case and has given a written permission for the authors to publish the report.

Back to Top | Article Outline


A 31-year-old male patient presented for surgery 18 hours after being involved in a high-impact road traffic collision. He was previously healthy, with no history of medication use or substance abuse. His recorded weight was 74 kg with a body mass index of 24 kg/m2. The planned procedure was bilateral open reduction and internal fixation of his forearm fractures. During the collision, he also sustained an injury of his cervical spine, namely avulsion fractures of the left occipital condyle, the left lateral mass of the C1, and undisplaced fractures of the spinous processes of the C4 and C5. Findings of the computed tomography (CT) scan showed normal cervical spine alignment and no spinal cord injury. The injuries were managed conservatively by immobilization of the neck in a hard cervical collar, with the use of blocks and tape. Log rolling was used when repositioning was required. A magnetic resonance imaging scan of the neck was planned to assess the stability of the craniocervical junction. His other injuries included traumatic dissection of the right distal carotid artery with formation of a pseudoaneurysm, a superior mediastinal hematoma, pulmonary hemorrhages, and an orbital fracture. Laboratory investigations showed normal plasma concentrations of sodium, potassium, magnesium, urea, and creatinine and a hemoglobin concentration of 143 g/L. Alcohol and toxicology screen was not performed.

On arrival to the anesthetic room, the patient was conscious and cooperative. The breathing pattern was regular and peripheral oxygen saturation was 91% to 94% on air and 97% on 2 L of oxygen via nasal cannula. Cardiovascular parameters were stable, and there was no neurologic deficit.

After preoxygenation, anesthesia was induced with fentanyl, propofol, and suxamethonium. The cervical collar was left in situ both during the induction and the intubation, and the manual in-line stabilization of the head and neck was applied after removal of the blocks and tape. Direct laryngoscopy with a size 4 Macintosh blade revealed a Cormack and Lehane grade 1 view of the larynx, and the trachea was easily intubated with a size 8.0 (8-mm internal diameter) tracheal tube. Intermittent positive pressure ventilation was commenced, anesthesia was maintained with sevoflurane in oxygen and air mixture, and the neuromuscular blockade was achieved with atracurium. A total of 10 mg morphine was administered intravenously (IV) for pain relief. Both the maintenance period of anesthesia and the operative procedure were uneventful.

At the end of the surgery, the neuromuscular blockade was reversed and the return of neuromuscular function confirmed by an adequate train of 4 assessment (T4:T1 ratio >0.9). Tracheal extubation was performed after adequate spontaneous ventilation returned and the patient opened his eyes to voice. The last recorded end-tidal CO2 reading before extubation was 37 mm Hg.

Shortly after the extubation, while being transferred from the operating table to the bed, the patient became very agitated and started rolling in bed. Because the patient’s neck was potentially unstable, an IV bolus of 2 mg of midazolam was administered to treat the agitation and allow the maintenance of the cervical spine protection. The patient instantly calmed down but shortly after that became unresponsive. A brief period of desaturation followed (the lowest peripheral oxygen saturation of 60%), which promptly responded to the administration of 100% oxygen.

No limb movement was observed after the period of agitation. Although spontaneous respiration continued at a rate of 14 breaths per minute and the blood pressure and heart rate remained within normal limits, worries arouse regarding the possibility of damage to the spinal cord caused by sudden, uncontrolled movements. The possibility of a stroke also was considered. The fact that there was no improvement in the level of consciousness with flumazenil only added to that concern.

After consultation with the neurosurgeon and the radiologist, an urgent CT scan of the head and neck was arranged. A decision was made to induce anesthesia and reintubate the trachea and commence mechanical ventilation. Tracheal intubation was achieved without difficulties; sedation was continued with IV infusion of propofol and mechanical ventilation facilitated with atracurium. An arterial blood gas analysis performed immediately after intubation showed severe respiratory acidosis, with a pH of 6.9 and a Paco2 of 120 mm Hg. After mechanical ventilation for an hour and after the CT scan was completed, the end-tidal carbon dioxide concentration normalized, and the patient started making purposeful movements (when the effect of atracurium was wearing off). The decision was made to transfer him to the intensive care unit (ICU) and to extubate in a controlled environment. The CT scan reported no new findings in the investigated head and neck areas. In the ICU, sedation and ventilation was continued and a magnetic resonance imaging scan of the head and neck performed on the following day showed a disruption of the atlanto-occipital alar ligament and a small focus of acute infarction in the subcortical white matter of the parietal lobule.

The injury of the cervical spine was managed conservatively with an immobilization in a hard cervical collar. During his subsequent stay on the ICU, the patient remained stable. Adequate oxygenation and ventilation was achieved with an inspired oxygen concentration of 28% and minimal support from the ventilator. Chest radiographs showed no evidence of acute respiratory distress syndrome or pulmonary contusions. The cardiovascular parameters, renal and liver function, and plasma electrolytes remained normal; however, the patient failed 2 sedation holds, each time as the result of severe agitation. The initial sedation regimen consisted of IV infusions of propofol (3–4 mg/kg/hr) and alfentanil (50–70 μg/kg/hr). IV infusion of clonidine (0.5–1 μg/kg/hr) was added to the sedation regimen after the second failed attempt at extubation. In addition, he received regular IV paracetamol for analgesia. Successful extubation finally was achieved 72 hours after the ICU admission with the use of an ongoing IV infusion of clonidine (0.5–1 μg/kg/hr). The rigid cervical collar was in place. Extubation was performed awake, with medications and equipment ready for reintubation. Because the intubation was previously easy, and respiratory insufficiency seemed unlikely, staged extubation with the use of an airway exchange catheter was not used. The clonidine sedation was discontinued after the patient remained calm and cooperative for 4 hours after extubation.

The patient was discharged from the ICU on the following day with no neurologic deficit and discharged home 2 weeks later.

Back to Top | Article Outline


This case report demonstrates that tracheal extubation, rather than intubation, can be the most challenging part of the anesthetic management of a patient with cervical spine injury. Severe agitation in our patient led to difficulties with immobilization of the neck, which was immediately recognized and acted on by the administration of a sedative drug. Unfortunately, severe respiratory depression and eventually reintubation and ICU admission followed. Hypercapnia and the potential cervical spine injury made the postextubation differential diagnosis difficult. Although we were not able to identify a definite cause, there are several possible factors that could have contributed to the agitation at emergence from anesthesia. The presence of a focus of cerebral ischemia as identified by postoperative CT scan and inadequate pain relief could have contributed. Considering the coexisting chest injuries and relatively low oxygen saturation before the induction of anesthesia, respiratory insufficiency due to pulmonary contusions and developing acute respiratory distress syndrome may have been another possibility. But this was later excluded during the ICU stay, as the pulmonary gas exchange was good and the patient required minimal respiratory support. The history of the use of alcohol or recreational drugs was denied by the patient; however, because the toxicology screen was not performed, agitation resulting from the use of or withdrawal from psychoactive substances remains on the list of differentials.

The case had a positive outcome, and it is essential to highlight this. Important questions arose however, whether the sequence of events could have been prevented, and if so, what would have been the most appropriate way of managing the tracheal extubation in this patient.

The stability of the spine has been defined as the ability of the spine to limit its pattern of displacement under physiologic loads so as not to allow damage or irritation of the spinal cord or nerve roots.4 The literature on airway management in patients with cervical spine injury has been focused mainly on tracheal intubation.2,5,6

Despite the fact that tracheal extubation is recognized as a phase of anesthesia with high risk of adverse events,1,7 there is paucity of literature regarding safe extubation practice in patients with unstable spine. Particularly in the context of cervical spine trauma, the term “airway management” has been used predominantly in relation to the methods of securing the airway. This may be partly attributable to the fact that the majority of publications on the subject relate either to acute trauma patients, in whom cervical spine may subsequently be cleared, or to patients undergoing spinal fixation, in whom the risk of secondary spinal injury on extubation is significantly reduced.5,8–11 Despite much literature on the topic, there is surprisingly few cases in the literature of intubation being associated with worsening of the cervical spine injury.12 There is evidence in the neurosurgical literature of ascending motor/sensory dysfunction in both surgically and nonsurgically managed cervical spine injuries, thought to be due to inflammation. This may make the effects of extubation even more difficult to study, as the timing of extubation (in many cases undertaken a few days later) would be in keeping with the dysfunction due to the natural course of the injury.

Conservative management, in the form of neck immobilization with nonsurgical tools, still plays an important role in the management of the cervical spine trauma.13 Instability of cervical spine is also encountered in nontrauma patients (eg, rheumatoid arthritis and other spondyloarthropathies). Such patients may present for surgery unrelated to their cervical spine, where, like in our patient, the cervical spine will remain unstable during the period of emergence and extubation.

Extubation is a core anesthetic skill and should be taught and practiced with the same attention to details as the intubation of the trachea. Difficult Airway Society UK guidelines for the management of tracheal extubation are the most comprehensive guidelines published to date on the subject of safe extubation of the difficult airway.7 Although not written specifically in relation to the management of patients with unstable cervical spine, the information provided is highly relevant to the clinical situation we encountered.

The guidelines emphasize the importance of planning for extubation before the start of anesthesia, as well as risk stratification, preparation, and the use of advanced extubation techniques in high-risk scenarios. Patients with the cervical spine instability may have neurologic disability as a general risk factor. In many cases, there will also be an additional risk factor, namely a difficult tracheal intubation caused by the manual in line stabilization, or a restriction of the access to the airway by a cervical collar or a halo vest. Therefore, in this group of patients, after optimization, extubation should follow the “at risk” algorithm.7

The aim of the anesthetic management during emergence and extubation of patients with confirmed or suspected cervical spine injuries is having a calm, cooperative patient in whom cervical spine can be protected. Possible complications during emergence in these patients can be broadly classified as: (1) agitation: this can be due to numerous causes including the pain, respiratory failure, cardiovascular instability, electrolyte imbalance, hypoxia, hypercapnia, increased intracranial pressure or cerebral ischemia, or withdrawal from substance abuse; (2) activation of airway reflexes caused by the presence of the endotracheal tube; and (3) airway complications occurring after the trachea is extubated, such as upper airway collapse and laryngospasm. These complications can result in the inability to maintain the immobilization of the neck or the need for an emergency reintubation of a potentially difficult airway, with all the associated risks.

The following methods should be useful in ensuring smooth emergence and recovery from anesthesia.

Prevention of agitation: Adequate pain control is paramount and can include multimodal analgesia and regional anesthesia. The risk of respiratory failure and cardiovascular instability is high in trauma patients.14 If diagnosed intraoperatively, it should prompt continuation of the mechanical ventilation in the postoperative period in the ICU. Hypoxemia attributed to respiratory insufficiency is an important cause of agitation and should always be considered as a possibility in patients with head and chest trauma. Electrolyte imbalances are also common in trauma patients, eg, attributable to rhabdomyolysis with renal dysfunction, massive blood loss, head injuries, or sepsis. Serum electrolyte concentration, renal function, and acid–base status should, therefore, be monitored. The substance abuse history should be sought, and a toxicology screen should be performed in this group of patients, as the use of alcohol and recreational drugs can cause agitation. It can also occur after withdrawal from long-term use of recreational drugs. Delirium during the ICU stay is a common occurrence and is associated mainly with factors related to the patient’s illness and comorbidities. Strategies that can be used to prevent delirium in patients ventilated on the ICU include avoidance of benzodiazepine sedation, appropriate pain management, daily spontaneous awakening and spontaneous breathing trials, and possibly prophylactic use of antipsychotics.15

Agitation during emergence is an obvious risk for patients in whom the cervical spine immobilization is required with a reported incidence of 3% and 6% in adult patients.16 Unfortunately, this phenomenon is still poorly understood and difficult to predict. Preoperative benzodiazepines, breast, abdominal, and musculoskeletal surgeries, age younger than 40 and older than 64 years, high postoperative pain scores, and long duration of surgery are recognized risk factors for this entity.16,17 One of the lessons to be learned from our case is that in patients with unstable cervical spine, it is vital to anticipate the possibility of emergence delirium and take all possible steps to prevent it. These include avoidance of premedication with benzodiazepines, adequate pain control, avoidance of a full bladder as well as unnecessary urinary catheters, and providing patients with eyeglasses and hearing aids as soon as possible. If delirium occurs on emergence, an effort to remind the patient of the situation should be made. In cases in which pharmacologic intervention is required, low-dose IV benzodiazepines or haloperidol could be used. If extubation is planned in the ICU setting, dexmedetomidine should be considered as a part of sedation regimen. A recent randomized, controlled trial of 74 ICU patients in whom extubation was considered inappropriate due to the severity of agitation found that addition of dexmedetomidine (up to 1.5 μg/kg/h) to current sedation regimen reduced the ventilator free hours at 7 days, reduced the time to extubation by a mean of 19.5 hrs, and accelerated the resolution of delirium.18

Because the presence of the endotracheal tube can cause agitation in its own right, it is very difficult to predict whether the patient is going to have persistent agitation after extubation. Hyde-Wyatt,19 in his review article on hyperactive delirium in patients with spinal immobilization in the intensive care setting, suggested that in these patients daily sedation holds, which are an important part of a ventilator care bundle, should be modified to sedation reductions. These should be carried out gradually to allow rapid detection of hyperactive delirium and resedation.

Back to Top | Article Outline


The use of a remifentanil infusion during extubation phase suppresses the activation of airway reflexes by the tracheal tube, minimizes coughing, straining, and agitation.20–22 We suggest that, in at-risk patients, the remifentanil technique could be used, allowing the patient to tolerate tracheal tube and assess the consciousness level and ability to obey commands before extubation occurs.

Intracuff local anesthetic or spraying the cords with local anesthetic also can be used in isolation or combined with the technique mentioned previously to smooth the emergence by suppressing the airway reflexes.23,24 Awake fiber-optic intubation is gaining popularity in patients with unstable cervical spine requiring general anesthesia.5,25 If performed, it may have an added advantage of smoothing the extubation, as after shorter surgical procedures the airway will still be anesthetized.

The laryngeal mask airway exchange technique has been used to avoid coughing, bucking, and agitation at emergence.26–28 Although this technique may allow smooth emergence, it is relatively contraindicated in emergency procedures where there is a risk of regurgitation and aspiration. Unlike airway exchange catheter, this technique does not facilitate tracheal intubation where reintubation is likely to be difficult.

Back to Top | Article Outline


Means of preventing upper airway collapse after extubation include ensuring that the neuromuscular blockade is fully reversed before extubation and avoidance of the excessive use of opioids and other long acting sedatives. Laryngospasm can be prevented by meticulous care to avoid the presence of blood and secretions in the airway and avoiding extubation and airway manipulation in light planes of anesthesia. Topical local anesthesia to airway also has been advocated. Its use is, however, controversial, because it may cause subjective dyspnea and therefore increase agitation. It has also been shown to reduce the peak inspiratory and expiratory flows in healthy volunteers.29

When the risk of postextubation complications is significant (obese patients, patients with obstructive sleep apnea, head and neck surgery) and difficulties with reintubation are predicted, the use of an airway exchange catheter is recommended.7 It does not necessarily smooth the emergence, but can be used to supplement oxygen if hypoxia occurs and as an aid to reintubation.

An alternative to early extubation in a patient with cervical spine injuries, who moves uncontrollably at emergence despite the use of one of the above-mentioned techniques, is to postpone the extubation

In patients with high risk of respiratory insufficiency, eg, in patients with coexisting chest injuries or respiratory disease, extubation should be delayed and gradual weaning using noninvasive ventilation should be considered. It may prevent agitation by preventing one of its most important causes—the respiratory insufficiency. A recent meta-analysis has shown that early use of noninvasive ventilation after surgery reduced reintubation rates and the length of the ICU stay.30

It is difficult to predict whether any of the aforementioned techniques would have prevented the occurrence of emergence agitation in our patient. Because emergence agitation is usually short-lived and lasts up to 30 minutes,31 one can speculate that the remifentanil technique would have allowed the patient to wake up more slowly, tolerating a cuffed tube within the trachea for a longer period of time, and therefore the residual effect of volatile anesthetic agents would have been reduced at the time of regaining consciousness, also reducing the risk of agitation at emergence. Topical airway anesthesia may have had similar effects. Optimizing patient’s analgesia by the use of multimodal techniques, eg, addition of acetaminophen, clonidine, or ketamine to opioid analgesic and the use of regional blocks or high volume local anesthetic infiltration could have prevented agitation caused by pain.

Major trauma centers should have guidelines on the preferred extubation technique for patients with cervical spine injuries who undergo general anesthesia and are to be extubated at the end of their surgery. Just like in cases of an expected difficult intubation, an extubation strategy, which is a coordinated series of plans, should be used. Advanced extubation techniques, such as extubation with the remifentanil infusion or an airway exchange catheter, or early use of the noninvasive ventilation should be considered. Dexmedetomidine has been shown to have beneficial effects on the resolution of delirium in ICU and should be considered in high-risk patients. All patients with cervical spine injury should be considered as “at risk” extubation. An extubation plan should be in place before induction of anesthesia. A postextubation care plan also should be formulated. At a minimum, it should include the location at which the patient will be monitored, the level of monitoring required, the next immediate step for managing agitation, the sedation technique, the oxygenation technique, means of monitoring ventilation (capnography), the choice of noninvasive ventilatory support (high flow nasal oxygen, continuous positive airway pressure, or bilevel positive airway pressure), and the preferred reintubation technique (awake intubation, videolaryngoscopy, or passing the tube over the existing airway exchange catheter). An extubation checklist involving the above factors may be a useful tool that aids the decision making process in these complex cases.

Back to Top | Article Outline


There is a risk of aggravating cervical spine injuries during or around the extubation time. It can easily distract the anesthesiologist and impact on their management of a dynamic and potentially complex scenario. The importance of careful planning of tracheal extubation and having a postextubation care plan in these patients cannot be overemphasized. Decision making can be difficult, and senior anesthetic staff should be present whenever possible during emergence, or, as a minimal, consulted for advice when this type of extubation takes place.

Back to Top | Article Outline


Name: Aleksandra Nowicka, MD.

Contribution: This author helped complete the article.

Name: Narcis Ungureanu, MD.

Contribution: This author helped complete the article.

Name: Shyam Balasubramanian, MD.

Contribution: This author helped complete the article.

Name: Cyprian Mendonca, MD.

Contribution: This author helped complete the article.

This manuscript was handled by: Richard Dutton, MD.

Back to Top | Article Outline


1. Quinn A, Woodall N. Cook T, Woodall N, Frerk C. The end of anaesthesia and recovery. 4th National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Major Complications of Airway Management in the United Kingdom. 2011:London: Royal College of Anesthiologists, 6270.
2. Crosby ET. Airway management in adults after cervical spine trauma. Anesthesiology. 2006;104:12931318.
3. Cavallone LF, Vannucci A. Review article: extubation of the difficult airway and extubation failure. Anesth Analg. 2013;116:368383.
4. White AA, Johnson RM, Panjabi MM, Southwick WO. Biomechanical analysis of clinical stability in the cervical spine. Clin Orthop Relat Res. 1975;109; 8596.
5. Hastings RH, Marks JD. Airway management for trauma patients with potential cervical spine injuries. Anesth Analg. 1991;73:471482.
6. Austin N, Krishnamoorthy V, Dagal A. Airway management in cervical spine injury. Int J Crit Illn Inj Sci. 2014;4:5056.
7. Popat M, Mitchell V, Dravid R, Patel A, Swampillai C, Higgs A. Difficult airway society guidelines for the management of tracheal extubation. Anaesthesia. 2012;67: 318340.
8. Criswell JC, Parr MJ, Nolan JP. Emergency airway management in patients with cervical spine injuries. Anaesthesia. 1994;49:900903.
9. Crosby E. Airway management after upper cervical spine injury: what have we learned? Can J Anaesth. 2002;49:733744.
10. Wood PR, Lawler PG. Managing the airway in cervical spine injury. A review of the advanced trauma life support protocol. Anaesthesia. 1992;47:792797.
11. Suderman VS, Crosby ET, Lui A. Elective oral tracheal intubation in cervical spine-injured adults. Can J Anaesth. 1991;38:785789.
12. Reade MC, Eastwood GM, Bellomo R, et al. Effect of dexmedetomidine added to standard care on ventilator-free time in patients with agitated delirium. A randomized clinical trial. JAMA. 2016; 315:14601468.
13. Lauweryns P. Role of conservative treatment of cervical spine injuries. Eur Spine J. 2010;19 (suppl 1):S23S26.
14. Casha S, Christie S. A systematic review of intensive cardiopulmonary management after spinal cord injury. J Neurotrauma. 2011;28:14791495.
15. Brummel NE, Girard TD. Preventing delirium in the intensive care unit. Crit Care Clin. 2013;29:5165.
16. Radtke FM, Franck M, Hagemann L, Seeling M, Wernecke KD, Spies CD. Risk factors for inadequate emergence after anesthesia: emergence delirium and hypoactive emergence. Minerva Anestesiol. 2010;76:394403.
17. Lepousé C, Lautner CA, Liu L, Gomis P, Leon A. Emergence delirium in adults in the post-anaesthesia care unit. Br J Anaesth. 2006;96:747753.
18. Duggan LV, Griesdale DE. Secondary cervical spine injury during airway management: beyond a ‘one-size-fits-all’ approach. Anaesthesia. 2015;70:769773.
19. Hyde-Wyatt JP. Managing hyperactive delirium and spinal immobilisation in the intensive care setting: a case study and reflective discussion of the literature. Intensive Crit Care Nurs. 2014;30:138144.
20. Lee B, Lee JR, Na S. Targeting smooth emergence: the effect site concentration of remifentanil for preventing cough during emergence during propofol-remifentanil anaesthesia for thyroid surgery. Br J Anaesth. 2009;102:775778.
21. Aouad MT, Al-Alami AA, Nasr VG, Souki FG, Zbeidy RA, Siddik-Sayyid SM. The effect of low-dose remifentanil on responses to the endotracheal tube during emergence from general anesthesia. Anesth Analg. 2009;108:11571160.
22. Nho JS, Lee SY, Kang JM, et al. Effects of maintaining a remifentanil infusion on the recovery profiles during emergence from anaesthesia and tracheal extubation. Br J Anaesth. 2009;103:817821.
23. Minogue SC, Ralph J, Lampa MJ. Laryngotracheal topicalization with lidocaine before intubation decreases the incidence of coughing on emergence from general anesthesia. Anesth Analg. 2004;99:12531257.
24. Birkinshaw KJ. Anaesthesia in a patient with an unstable neck. Morquio’s syndrome. Anaesthesia. 1975;30:4649.
25. Meschino A, Devitt JH, Koch JP, Szalai JP, Schwartz ML. The safety of awake tracheal intubation in cervical spine injury. Can J Anaesth. 1992;39:114117.
26. Miller KA, Harkin CP, Bailey PL. Postoperative tracheal extubation. Anesth Analg. 1995;80:149172.
27. Dob DP, Shannon CN, Bailey PM. Efficacy and safety of the laryngeal mask airway vs Guedel airway following tracheal extubation. Can J Anaesth. 1999;46:179181.
28. Costa e Silva L, Brimacombe JR. Tracheal tube/laryngeal mask exchange for emergence. Anesthesiology. 1996;85:218.
29. Liistro G, Stănescu DC, Veriter C, Rodenstein DO, D’Odemont JP. Upper airway anesthesia induces airflow limitation in awake humans. Am Rev Respir Dis. 1992;146:581585.
30. Glossop AJ, Shephard N, Shepherd N, Bryden DC, Mills GH. Non-invasive ventilation for weaning, avoiding reintubation after extubation and in the postoperative period: a meta-analysis. Br J Anaesth. 2012;109:305314.
31. Sanders RD, Pandharipande PP, Davidson AJ, Ma D, Maze M. Anticipating and managing postoperative delirium and cognitive decline in adults. BMJ. 2011;343:d4331.
Copyright © 2016 International Anesthesia Research Society