Incidence of Laryngotracheal Stenosis after Thermal Inhalation Airway Injury

Long-Term Laryngotracheal Complications After Inhalation Injury: A Scoping Review

Long-term laryngotracheal complications (LTLC) after inhalation injury (II) are an under-recognized condition in patients with burns. The purpose of this study was to systematically review all available evidence on LTLC after II and identify gaps in knowledge to guide the direction of future research. A scoping review was performed to synthesize all available evidence on LTLC after II, as guided by the question, "What are the LTLC after II, in patients with or without a history of translaryngeal intubation and/or tracheostomy?". MEDLINE, Web of Science, Ovid Embase, Cochrane Library, and Google Scholar were searched for publications on this topic. Of the 3567 citations screened, a total of 153 full-text articles were assessed for eligibility and 49 were included in the scoping review. The overall level of evidence was low, with case reports constituting 46.7% of all included human studies. The lesions were most frequently in the trachea (36.9%), followed by the glottis (34.7%) and subglottis (19.0%). LTLC occur in 4.8 to 6.5% of patients after II and these complications are under-recognized in burns patients. The risk factors for LTLC include high-grade II, elevated initial inflammatory responses, prolonged translaryngeal intubation, and a history of tracheostomy. The goal of management is to restore airway patency, preserve voice quality, and restore normal diet and swallow function. There is limited high-level evidence on LTLC, particularly with regards to long-term functional morbidity in voice and swallow. Large, prospective studies are required to address this gap in knowledge.

Long-term laryngotracheal complications following cardiac surgery

BACKGROUND AND AIM OF THE STUDY

Long-term laryngotracheal complications have not been described in adult patients undergoing cardiac surgery. The purpose of this study was to determine the incidence of and risk factors for laryngotracheal complications following cardiac surgery.

METHODS

A retrospective chart review of patients at high risk for laryngotracheal complications following cardiac surgery between 2006 and 2016 was performed. High-risk patients were reviewed to determine the presence of laryngotracheal complications including laryngotracheal stenosis, keyhole deformity, or vocal cord immobility. Logistic regression was used to identify predictors of long-term laryngotracheal complications.

RESULTS

Of 11,417 patients who underwent cardiac surgery, 1099 were identified as at high risk. Of these, 24 (2.2%) developed laryngotracheal complications following their surgery and intensive care unit (ICU) stay. Laryngotracheal stenosis and keyhole deformity were present in 13 (1.2%) and 6 (0.5%) patients, respectively. Logistic regression demonstrated older age (age ≥ 70 odds ratio [OR] 0.31, 95% confidence interval [CI] 0.12-0.83) was protective, while readmission to ICU for ventilation (OR 3.11, 95% CI 1.17-8.25) and receiving a tracheostomy (OR 7.83, 95% CI 2.22-27.6) were associated with laryngotracheal complications.

CONCLUSIONS

The incidence of long-term laryngotracheal complications following cardiac surgery was 2.2%. Readmission to ICU for ventilation and having a tracheostomy performed were associated with laryngotracheal complications.

Inhibition of extracellular signal-regulated kinase pathway suppresses tracheal stenosis in a novel mouse model

Tracheal stenosis is a refractory and recurrent disease induced by excessive cell proliferation within the restricted tracheal space. We investigated the role of extracellular signal-regulated kinase (ERK), which mediates a broad range of intracellular signal transduction processes in tracheal stenosis and the therapeutic effect of the MEK inhibitor which is the upstream kinase of ERK. We histologically analyzed cauterized tracheas to evaluate stenosis using a tracheal stenosis mouse model. Using Western blot, we analyzed the phosphorylation rate of ERK1/2 after cauterization with or without MEK inhibitor. MEK inhibitor was intraperitoneally injected 30 min prior to cauterization (single treatment) or 30 min prior to and 24, 48, 72, and 96 hours after cauterization (daily treatment). We compared the stenosis of non-inhibitor treatment, single treatment, and daily treatment group. We successfully established a novel mouse model of tracheal stenosis. The cauterized trachea increased the rate of stenosis compared with the normal control trachea. The phosphorylation rate of ERK1 and ERK2 was significantly increased at 5 min after the cauterization compared with the normal controls. After 5 min, the rates decreased over time. The daily treatment group had suppressed stenosis compared with the non-inhibitor treatment group. p-ERK1/2 activation after cauterization could play an important role in the tracheal wound healing process. Consecutive inhibition of ERK phosphorylation is a potentially useful therapeutic strategy for tracheal stenosis.

Laryngeal inhalational injuries: A systematic review

Laryngeal inhalation injury carries a significant increase in mortality rate and often indicates immediate airway evaluation. This may be difficult in the setting of clinical deterioration necessitating immediate intubation, which itself can synergistically cause mucosal damage. Prior studies do not encompass predictive factors or long-term outcomes for the laryngotracheal complex. This systemic review of PubMed, Embase, and Cochrane identified studies investigating inhalational injuries of the upper airway. Demographic data as well as presentation, physical findings, and delayed sequelae were documented. Laryngotracheal burn patients were divided into two cohorts based on timing of laryngeal injury diagnosis (before- versus after-airway intervention). 1051 papers met initial search criteria and 43 studies were ultimately included. Airway stenosis was more common in patients that were intubated immediately (50.0%, n = 18 versus 5.2%, n = 13; p = 0.57). Posterior glottic involvement was only identified in patients intubated prior to airway evaluation (71.4%, n = 15). All studies reported a closed space setting for those patients in whom airway intervention preceded laryngeal evaluation. Laryngeal inhalational injuries are a distinct subset that can have a variety of minor to severe laryngotracheal delayed sequelae, particularly for thermal injuries occurring within enclosed spaces. Given these findings, early otolaryngology referral may mitigate or treat these effects.

Inpatient and post-discharge outcomes following inhalation injury among critically injured burn patients

Inhalation injury is associated with high inpatient mortality, but the impact of inhalation injury after discharge and on non-mortality outcomes are poorly characterized. To address this gap, we evaluated the effect of inhalation injury on post-discharge morbidity, mortality and hospital readmissions among patients who sustained burn injury, as well as on in-hospital outcomes for context.This was a retrospective cohort study of patients with cutaneous fire/flame burns admitted to a burn center intensive care unit from 1/1/2009-12/31/2015, with or without inhalation injury. Records were linked to statewide hospital admission and vital statistics databases to assess post-discharge outcomes. Mixed-effects Poisson regression was used to assess mortality, complications, and readmissions. The overall cohort included 830 patients with cutaneous burns; of these, 201 patients had inhalation injury. In-hospital mortality was 31% among inhalation injury patients versus 6% in patients without inhalation injury (adjusted OR 2.35; 95% CI 1.66-3.31). Inhalation injury was also associated with an increased risk of in-hospital pneumonia and tracheostomy (p<0.05 for all). Inhalation injury was not associated with greater post-discharge mortality, all-cause readmission, readmission for pulmonary diagnosis, or readmission requiring intubation. Among the subset of patients with bronchoscopy-confirmed inhalation injury (n=124; 62% of inhalation injuries), higher injury grade was not associated with greater inpatient or post-discharge mortality. Inhalation injury was associated with increased early morbidity and mortality, but did not contribute to post-discharge mortality or readmission. These findings have implications for shared decision-making with patients and families, and for estimating healthcare utilization after initial hospitalization.

Laryngotracheal Reconstruction in the Pediatric Burn Patient: Surgical Techniques and Decision Making

The management of laryngotracheal stenosis (LTS) in the pediatric burn patient is complex and requires a multidisciplinary approach. The mainstay of treatment for LTS is laryngotracheal reconstruction (LTR), however, limited reports of burn-specific LTR techniques exist. Here, we provide insight into the initial airway evaluation, surgical decision making, anesthetic challenges, and incision modifications based on our experience in treating patients with this pathology. The initial airway evaluation can be complicated by microstomia, trismus, and neck contractures-the authors recommend treatment of these complications prior to initial airway evaluation to optimize safety. The surgical decision making regarding pursuing single-stage LTR, double-stage LTR, and 1.5-stage LTR can be challenging-the authors recommend 1.5-stage LTR when possible due to the extra safety of rescue tracheostomy and the decreased risk of granuloma, which is especially important in pro-inflammatory burn physiology. Anesthetic challenges include obtaining intravenous access, securing the airway, and intravenous induction-the authors recommend peripherally inserted central catheter when appropriate, utilizing information from the initial airway evaluation to secure the airway, and avoidance of succinylcholine upon induction. Neck and chest incisions are often within the TBSA covered by the burn injury-the authors recommend modifying typical incisions to cover unaffected skin whenever possible in order to limit infection and prevent wound healing complications. Pediatric LTR in the burn patient is challenging, but can be safe when the surgeon is thoughtful in their decision making.