Indian Journal of Burns

REVIEW ARTICLE
Year
: 2021  |  Volume : 29  |  Issue : 1  |  Page : 7--11

Airway management in patients with neck burn contracture


Nidhi Gupta1, Tanmay Tiwari2, Haider Abbas3,  
1 Department of Anaesthesiology and Critical Care, AIIMS, Rishikesh, Uttarakhand, India
2 Department of Anaesthesiology and Critical Care, King George's Medical University, Lucknow, Uttar Pradesh, India
3 Department of Emergency Medicine, King George's Medical University, Lucknow, Uttar Pradesh, India

Correspondence Address:
Dr. Nidhi Gupta
Department of Anesthesiology and Critical Care, AIIMS, Rishikesh, Uttarakhand
India

Abstract

Airway management is an important aspect during reconstructive surgeries of patients with postburn contracture (PBC) due to significant morbidity and mortality associated with it. The standard recommendations by the American Society of Anesthesiologists for Difficult Airway Management may not be appropriate for these patients due to the high risk of intubation failure and airway crisis. With recent advancements, many techniques and devices have been used successfully in patients with PBC of the head and neck. This article focuses on various barriers faced during the airway management of such patients along with common techniques to overcome them.



How to cite this article:
Gupta N, Tiwari T, Abbas H. Airway management in patients with neck burn contracture.Indian J Burns 2021;29:7-11


How to cite this URL:
Gupta N, Tiwari T, Abbas H. Airway management in patients with neck burn contracture. Indian J Burns [serial online] 2021 [cited 2022 Jul 5 ];29:7-11
Available from: https://www.ijburns.com/text.asp?2021/29/1/7/346908


Full Text



 Introduction



Burn injury trauma remains the second most common trauma-related morbidity after motor vehicle accidents. Even with the best treatment, postburn contracture (PBC) cannot be avoided in some cases, since they are dependent on the depth of burns. Deeper burns heal by scarring which may be minimized by physical therapy and procedures done by plastic surgery but not eliminated. Hence, for most of the time, inappropriately managed burn cases present with contractures. Contractures developing postburn injury are a well-established complication with a prevalence of 38%–54% postdischarge.[1]

There is a high incidence of PBC in our country thus constituting a major caseload in the plastic surgery department for reconstructive surgeries. They can decrease the quality of life and cause various deformities such as joint contracture and scars. Along with this, there is a psychological impact too.[2] The contractures can be present at various sites commonly being axilla, elbow, hand, neck, and face.[3]

 Patient Preparation and Anaesthesia Concerns



Patients with burn contracture impose many challenges on anesthetist. These include difficult airway, poor venous access, problem in the attachment of monitors, drug dosing, hypothermia, and blood loss estimation. However, difficult airway management remains the major concern due to significant morbidity and mortality associated with it.[4]

A detailed history is a prerequisite for the anesthetic management of such cases so that we can estimate the level of airway difficulty and prepare accordingly.

Cause and time of burn injury should be obtained in history (thermal, chemical, or electrical) along with snoring history which may indicate difficult mask ventilation postinduction.

Patients with inhalational injury may have tracheal stenosis which may interfere with tracheal tube placement.

Difficulty in intubation is generally because of the following reasons.

Reduced oropharyngeal space due to burning scarring thus limiting space for visualization with the direct laryngoscope (D. L)Limited extension of atlanto-occipital jointDecreased submandibular compliance which prevents tongue compression during laryngoscopy, giving an anterior appearance of the larynxRestricted mouth opening due to cicatrization of angles of the mouthObliteration of nasal passages.

The fixed flexion deformity of the neck leads to improper positioning, hence causing nonalignment of the oral, pharyngeal and laryngeal axes during intubation.[5]

The risk associated with difficult airway management should be well explained to the patient or/and the accompanying person. Informed consent must be obtained.

 Airway Examination



Preoperative airway evaluation is important to assess airway difficulty level and plan alternate strategies for airway management. This includes a detailed history and physical examination.

In burn patients, the airway may become progressively more difficult as neck contracture worsens. The airway evaluation assesses anticipated difficulty with ventilation, intubation, or both and it must be done in the sitting position rather than supine or semi-fowlers. Furthermore, examination of scar and contracture should be performed along with routine assessment. In addition to this, special focus should be given on perinasal and circumoral regions and the size of the nasal and oral orifices. Mouth opening may be limited by mentosternal contractures.[6]

Some of the routine parameters of difficult airway assessment may not be applicable in PBC patients. Classical Mallampati test is done with the head in the neutral position; in PBC neck, it is possible only in the flexed neck position.

To predict difficult laryngoscopy, lateral cervical radiograph can be done.

Although it is difficult to assess the thyromental distance and sternomental distance precisely because of anatomical distortion, a rough estimation may be done in few selected cases.[7]

To summarize, airway features such as inter incisor distance <3 cm, sternomental distance <12 cm, mallampati class >2, range of neck movement <80 degree, limited head extension indicates difficult airway.

Neck imaging (both anteroposterior and lateral view) may provide information regarding naso or oropharyngeal space, deviation of the larynx or trachea, and compression of the airway.

 Anaesthesia Technique



With anticipated difficult intubation, a variety of instruments are kept prepared. These include various sizes and types of laryngoscope blades and endotracheal tubes, supraglottic devices, fibreoptic bronchoscope, tracheostomy kit and video laryngoscope (V. L).

The anesthesia technique used for PBC is usually both regional and general anesthesia. This depends on burn/scar area, patient's age and weight, any associated disease, skill of the operating surgeon and availability of resources.[8]

Regional anesthesia using local anesthetic drugs is however not suitable for raw area more than 10% and patients <18 years of age and risk of toxicity also present with large doses.

 Tumescent Anaesthesia



In 1964, Tanzer. first described the technique of neck contracture release before intubation. With anticipated difficulty in the airway, the inferior half of the neck can be released under local anesthesia. After gaining partial extension of the neck, endotracheal tube may be introduced and superficial dissection continued.[9]

Goswami et al. successfully managed two patients with PBC necks. The local anesthesia was given at the site along with sedation (Inj. Ketamine) for surgical release of contracture followed by a routine conventional method of laryngoscopy.[7]

Tumescent anesthesia is a local anesthesia technique for extensive regional anesthesia of the skin and subcutaneous tissue. A large volume of lignocaine and epinephrine is infiltrated subcutaneously which causes the targeted area to swell up and become tensed (tumescent), thus allowing procedures to be performed smoothly without the inherent risk of toxicity. However, the local anesthetic agent dose may easily exceed the maximum safe limit.

Along with this injecting the drug through a thick scar is quite painful and also it is difficult to assess the depth and plane of injection.[10]

Henceforth, a combined technique using an intravenous sedating agents like ketamine with or without local infiltration of the site and immediate cutting of scar is a preferable choice.[11],[12] It is safe and effective technique.

General anesthesia can be given either as awake intubation, a percutaneous technique or while maintaining spontaneous breathing. For airway management, various newer devices are also available and used particularly in difficult scenarios.[13]

 Approach to Airway Management



There are various approaches to airway management of contractures involving the face, neck, and chest. These include contracture release under tumescent anesthesia (as described above) supplemented with sedation and analgesia followed by intubation, awake intubation using a fiberoptic bronchoscope, use of supraglottic devices, video laryngoscopy devices such as airtraq, glidescope or eventually tracheostomy, or cricothyroidotomy which are the emergency procedures.

Blind nasal intubation can be considered if nostrils are patent and other modalities are not available. However, there may be limited positioning of the head and neck and repeated attempts can increase the risk of nasal bleeding, which may further endanger the airway.

Retrograde-guided intubation with a catheter inserted through the cricothyroid membrane is similarly not favorable in the majority of the cases as anatomical reference points are obscured. According to the American Society of Anesthesia Difficult Airway Algorithm guidelines, alternate methods of securing the airway should be attempted after failure of standard attempts at direct laryngoscopy.[14] Given the exceptional nature of the airway of patients with PBC, alternative approaches are preferred as initial approach over routine measures. Hence, intubation is first attempted with indirect laryngoscopy methods.[15]

Common devices used as approach for securing the airway in PBC patients are described below.

 Supraglottic Airway Devices



The laryngeal mask airway (LMA) plays a key role in the difficult airway mainly as rescue device or as an aid to tracheal intubation, although they have been used as a definite airway also. They can be used either blindly or with fiberoptic guidance. However, due to anatomical abnormalities, it may not be correctly placed and may be displaced by intraoperative position.

Besides classical LMA (cLMA) other supraglottic devices such as Pro-Seal LMA, intubating LMA (ILMA), I-gel and laryngeal tube may also be used.[16] LMA can also be used successfully in scenarios like in a cannot ventilate cannot intubate situation as a bridge to restore the airway. Gupta and Sahni. reported successful airway management of a 20-year-old female with orofacial, neck and trunk burns who presented for contracture release, using ProSeal laryngeal mask airway with tube exchanger (without introducer) after failed fibreoptic bronchoscopy (FOB) attempt.[17]

Few case reports have been described where ILMA and AMBU LMA (ALMA) has been introduced via upside down or 180° technique for securing the airway and endotracheal intubation in patients with extreme flexion neck deformity with small mouth opening.[18],[19]

I gel has also been reported to be successfully used in such patients.

Singh et al. a study comparing I-gel with cLMA postburn patients with neck contracture and found that I-gel allowed effective controlled ventilation in 91.7% in the first attempt, however with cLMA this was possible only in 79.16%.[20]

I gel is a cheap, effective airway device that is easier to insert and has better clinical performance in difficult airway management.

 Fibreoptic Bronchoscope



FOB has been the gold standard in airway management in spontaneously breathing patients with an anticipated difficult airway.[21]

It has been established as the safest effective alternative to direct laryngoscopy and has been commonly described in patients with PBC of the neck. The head and neck and be maintained in a neutral position during airway management thus limiting flexion and extension. Along with this protective reflexes can be maintained thus reducing the risk of aspiration. However, it requires sufficient time, technical skills and cooperation of the patient. In addition to this, it has a long-learning curve and may not be available in every setup.[22]

FOB can be done through the oral or nasal route. In general, the nasal route is considered easier because the angle of curvature of the endotracheal tube corresponds naturally with that of the upper airway. The oral route can be more difficult technically as while advancing tube over fiberscope, it tends to move posteriorly to glottis into the esophageal inlet. This issue can be overcome by using commercially available airways which create a more anterior curvature that provides an alternate channel.[23]

These include Williams Airway Intubator, the Ovassapian Fibreoptic Intubating Airway and the Berman oropharyngeal airway. However these airways cannot be placed in patients with microstomia because of oral cicatrization.

 Other Devices



For airway management, various newer devices are also available and used mainly in difficult scenarios. The Airtraq® laryngoscope is a recently introduced optical intubation device that has an extreme blade curvature. This along with optical components helps in visualization of the glottis without the need for aligning the three airway axes, i.e., oral, pharyngeal, and laryngeal.

Ali et al. conducted a case series of five patients with severe burn contracture involving face and neck presenting with flexion deformity and distortion of the mouth opening leading to the difficult airway and were successfully intubated using Airtraq®. Due to its cost-effectiveness, better learning curve, easy handling and usefulness in critical scenarios airtraq is considered better than fiberoptic bronchoscope.[24]

Gupta and Sahni conducted a comparative study between V. L and D. L and concluded that intubation with a V. L (King Vision) was easier than with DL in patients with mild-to-moderate contracture neck with mouth opening >3 cm and Miles per gallon I/II.

The laryngeal anatomy was better visualized (improved Cormack Lehane grade) with V. L which lead to smooth intubation with less need of optimizing maneuvers and adjuncts.[17]

The esophageal-tracheal Combi-tube although is not very popular as an airway device for patients posted for elective surgery under general anesthesia. Although few cases have been mentioned in the literature, Hagberg et al. reported one such case of a 50-year-old patient in whom they successfully used the Combi-tube to secure and maintain a difficult airway. The patient had a history of facial burn causing contracture around the mouth and significant tracheal stenosis after intubation for prolonged duration.[25]

 Tracheostomy



Even though considered a last resort for airway management, tracheostomy may not be possible in some cases due to neck fibrosis and loss of anatomical landmark. Furthermore, there are various complications associated with it which include surgical emphysema, bleeding causing airway obstruction, leaks and edema. Vathulya mentions a case of PBC with failed intubation, they gave muscle relaxant followed by tracheostomy and then releasing some contracture followed by endotracheal intubation.[26]

Overall, it is important to keep a backup strategy for airway management in case of failure of primary management.

 Conclusion



Airway management in a patient with PBC requires a thorough understanding of difficult airway so that meticulous preparation can be done before taking up the case for surgery. While factors such as limited mouth opening, reduced atlanto-occipital joint extension, poor submandibular compliance, and neck fibrosis contribute a major challenge in airway management, additional elements such as microstomia and obliteration of nasal passage further worsen the scenario. Even though awake fiberoptic bronchoscope-guided nasotracheal intubation is the gold standard approach for securing an airway, others options such as LMA, retrograde intubation, blind nasal intubation, and tracheostomy may also be considered provided neck anatomy is not distorted and mouth opening is adequate. Recently, VL devices are also being used for the same. Since oral fiberoptic intubation can be technically more difficult, the availability of a wide variety of oral airways provides a clear visual path from the mouth to the pharynx and aids in successful intubation. Considering all the above factors judicious preparation along with proper teamwork involving surgeon and anesthesiologist is required for successful management of such challenging cases.

Due to nonavailability of standard guidelines in such cases, clinical judgment of anesthetist is of paramount importance to prevent any catastrophic event.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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