2017-18 HSC Section 3 Green Book

Journal of Voice, Vol. 31, No. 3, 2017

intubation in difficult airways or the use of an inadequate tube were noted to cause an increase in the incidence of tracheal lac- erations or esophageal perforations. 14 This, combined with transportation and regularly repeated dressing changes around the neck, may cause neck extension, which subsequently leads to cephalic movement of the ETT tube producing dislodgment and superficial mucosal trauma. In burn patients, this may prove fatal from hypoventilation and hypoxia. 14,15 Additionally, with high volumes of fluid resuscitation, those with severe burns risk fluid maldistribution, resulting in pulmonary edema and tissue edema to the affected skin. 12 This can contribute to the difficul- ty faced with reintubation, making it virtually impossible due to the extent of airway constriction from edema. 14,16 Due to the nature of the position of the endotracheal tube resting on the posterior glottis, 5 this area is particularly prone to pressure necrosis, ulceration, and granulation, which can in turn result in fibrosis and the development of a posterior glottic web. 17 Gastroesophageal reflux is also a key etiological factor in postglottic stenosis after prolonged endotracheal intubation. 18 Collectively, this can then progress to cicatriza- tion, which on extubation may be potentially life-threatening requiring urgent surgical management. 17,19 The first-line surgi- cal management is often transoral CO 2 laser microsurgery. This elegant surgical technique maintains the integrity of the vocal tract and frequently avoids the use of a tracheostomy. 17 Restenosis, however, is a common complication and may prompt laryngotracheal reconstruction with or without mitomy- cin C. Advocates of this procedure describe entry to the larynx through a laryngofissure and resection of the scarred mucosa and interarytenoid muscle, which may require skin or mucosal flap reconstruction. However, failure of this technique may prompt more extensive surgical intervention, which by its nature may be disfiguring and result in a longer recovery period. 17,19 Such webbing can be very challenging to recon- struct, with initially successful cases often resulting in significant dysphonia and potential airway obstruction requiring long- term tracheostomy. 20 As such, once a patient has been intubated for longer than a few days, there should be serious consider- ation of a potentially short-term tracheostomy. 10,16 The gold standard for airway management is tracheostomy. Ventilation is improved by a reduction in dead space, and tube changes in those with airway disease have less morbidity than endotracheal tube change. 15 In those with inhalation injury, “resting the larynx” minimizes the aforementioned sequelae of prolonged endotracheal intubation. The most common long- term complication of tracheostomy is subglottic stenosis, often secondary to necrosis of respiratory epithelium due to local- ized long-term static cuff pressure. 12,15 This effect has been minimized by the introduction of measurable cuff pressure and reduced ventilation volumes. 16 On development of stenosis, it is felt that subglottic stenosis is simpler to treat surgically than glottic stenosis. Dependent on the degree of stenosis, an array of techniques are available. Cotton-Myer grade 1 is often as- ymptomatic, whereas grades 2–4 require surgical intervention. 21 Whereas grade 2 stenosis can successfully be managed with endotracheal balloon dilatation, grades 3 and 4 often require open reconstruction or excision of the stenotic segment. These

dressings once the grafted areas were stable. Following dis- charge 12 weeks postinjury, the skin grafts had mainly healed, with some scattered areas of overgranulation. These were treated with application of Terra-Cortril ® ointment (oxytetracycline hy- drocortisone) (Alliance pharmaceuticals Ltd. Chippenham, Wilshire, UK), and later with cream (silver sulfadiazine 1%) and Biatain® Soft-Hold (Coloplast Ltd, Oxford, Oxfordshire, UK). The postburn scarring was treated with a combination of mois- turizing and massage and pressure garments. DISCUSSION The effect of inhalation injury on the lower respiratory tract has been described in depth in the literature. The natural progres- sion includes direct mucosal injury as far as the bronchioles as a consequence of thermal injury, resulting in epithelial damage and an intense inflammatory response. This arises from the effect of chemical injury, resulting in edema and the inhibition of oxygen transport, producing tissue hypoxia. 4,5,10 When assessing a patient with potential airway compro- mise, one should pay attention to oral commissure edema that occurs within minutes to hours, mucosal hemorrhage and ul- cerations, soot around the nasal aperture, burnt facial hair, and dysphonia. 10,11 Petroff et al demonstrated that two-thirds of pa- tients with inhalation injuries present with features of facial burns. 11 Conversely, Robinson and Miller reported that over 85% of patients with specifically upper respiratory tract burns may have no facial features as heat exposure is not essential to in- stigate chemical burns. 10 Thus, the patient’s physical appearance is only a minor determinant when instigating the method of burn management. This report attempts to unveil the effect on the upper airway, with discussion regarding immediate and later manage- ment considerations when treating those with similar insults. The first priority in the management of those with inhala- tion injury is to secure the airway. Options include conservative close monitoring for progression of symptoms, endotracheal intubation, or immediate tracheostomy. 5,10,12 Clinical indica- tions for active airway management include edema of the upper airway on endoscopy, circumferential burns to the neck, or progressive central nervous system depression. Lund et al de- scribed that, in the non-burn population, there is significant risk of long-term laryngeal injury consisting of laryngeal ste- nosis, tracheal stenosis, and granulation formation if intubated for more than 3 weeks, irrespective of oral or nasotracheal intubation, 12 whereas Gaissert et al described a series of 18 patients intubated with inhalation injuries. 13 In those with in- halation injuries, the degree of trachea damage originating from the subglottic space was far more extensive and occurred in patients intubated for as little as 6–10 days in contrast to 3 weeks described risk of postintubation stenosis in patients without inhalation injuries. 5,11,13 Endotracheal intubation, when possible, is a fast and effec- tive means by which to secure the airway; however, it is not without complications. Divatia and Bhowmick described an ex- tensive list of Endotracheal Tube (ETT) complications. Some of these include the ETT causing a reflex bronchospasm insti- gating bronchoconstriction. Additionally, multiple attempts at

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