Supraglottic Airway Obstruction

Article Author:
Virteeka Sinha
Article Editor:
Jeanie Skibiski
Updated:
6/29/2019 12:34:32 AM
PubMed Link:
Supraglottic Airway Obstruction

Introduction

Supraglottic obstruction is a medical or surgical emergency. It can result in increased work of breathing and respiratory distress and can progress to fatal cardiopulmonary arrest. Prompt correction of the causative factor can relieve obstruction and lead to improvement of the respiratory and cardiac status as well as the mental status of the child.

The pediatric airway is at increased risk for fatal outcomes from obstruction owing to narrow calibers, the position of the larynx, a large tongue, and the poor tone of the pediatric patient. Deterioration from a patent airway to a partial obstruction and progress to a complete obstruction can take place rapidly. Rapid recognition, prompt correction, and intervention to relieve airway obstruction can be life-saving.

Supraglottic obstruction can be acute or chronic and can present as partial obstruction or complete obstruction. Careful assessment of the airway is important, keeping in mind, not to agitate or aggravate the child's distress and anxiety, which can, in turn, worsen respiratory distress.[1][2][3]

Etiology

Etiology can be acute or chronic.  In obtunded patients, the tongue is the most common cause of upper airway obstruction.[4]  Acute causes of supraglottic obstruction include laryngotracheobronchitis, or croup, foreign body aspiration, epiglottitis, allergic reaction or anaphylaxis, acute bacterial tracheitis, burns to the face or oral cavity, retropharyngeal abscess, peritonsillar abscess and causes of upper airway edema or swelling. Chronic causes of supraglottic obstruction include laryngomalacia, tracheomalacia, laryngeal cysts or hemangiomas, obstructive sleep apnea or chronic compression from malignancies or lymphomas. The obstruction presents as stridor, a harsh vibrating sound heard best during inspiration. The level of obstruction directly corresponds to the intensity of the stridor. Etiology may not be clear on initial presentation, and key factors in history and examination have to be taken into account.[5][6][7]

Airway obstruction may be classified into either infectious, inflammatory or neoplastic[8]

Inspiratory stridor represents supraglottic obstruction while expiratory stridor originates at or below the glottis level. [9] Transient swelling of the lips, tongue, pharnyx and laryngx may be caused by angioedema. The swelling may occur rapidly and may emergently obstruct the airway.[10]

In neonates there are several congenital craniofacial anomalies that are associated with airway obstruction. These include craniofacial clefts, Pierre Robin sequence, midface hypoplasia, achondroplasia and Down syndrome may have micrognathia, obstructive sleep apnea or tongue-based airway obstruction.[11]

Epidemiology

Viral agents most often cause upper airway obstruction in the pediatric age group. Bacterial causes like diphtheria, bacterial tracheitis, and epiglottitis are fairly uncommon especially since the introduction of vaccination with Haemophilus influenzae type b Haemophilus influenzae type b (Hib) and Pneumococcal vaccines. Males are commonly more affected by croup. Viruses like parainfluenza and influenza are the most common viral etiological agents.

Foreign body aspirations are common in young children between 2 to 5 years of age. Laryngomalacia is a  chronic cause of upper  airway obstruction and is the most common laryngeal anomaly in the infant age group.[12]

Odynophagia may be indicative of peritonsillar (quinsy) lingual or retropharyngeal abscess formation.[13][14][15][16]

Pathophysiology

Supraglottic obstruction in pediatric patients is more common in children than in adults with a similar illness, and this is due to factors that make the pediatric airway more susceptible to airway obstruction and distress. The pediatric airway is narrower and more prone to obstruction. The relatively high larynx, larger head, large tongue, poor tone, increased compliance which predisposes to kinking, and the narrowest diameter at the cricoid make the pediatric airway increasingly challenging. Air flowing in and out of a more limited airway flows under greater resistance. This results in stridor for upper airway obstruction and wheezing for lower airway obstruction. The presence of stridor indicates the loss of 50% of the airway diameter. [17] Airway inflammation and infections accelerate the edema around the airway. This worsens obstruction and respiratory distress. Most common findings associated are stridor/ noisy breathing, respiratory distress, and tachypnea with improper aeration of the lower airways. Increasing rates of immunizations with Hib and Streptococcal vaccines have resulted in a dramatic decrease in upper airway infections and inflammation. This has led to a dramatic decrease in rates of intubation or invasive interventions to relieve airway obstruction.

Angioedema has multiple mechanisms, but a common presentation.  Histamine-mediated  angioedema results in mast cell degranulation.  Bradykinin-mediated angioedema results from an overproduction of bradykinin due to  either an acquired or inherited C-1 deficiency. [10]Angioedema may also be caused by certain drugs such as angiotensin-converting enzyme inhibitors.[18]

Oversedation during procedures may contribute to airway obstruction and adverse events. In closed-claims analysis, 24% of liability claims during sedation were related to respiratory events.[19]

Neck hematomas may obstruct the upper airway by external compression of the trachea. These may occur post-surgery or due to trauma (blunt and penetrating)

or post-extubation.

History and Physical

History depends on the age of presentation of the patient. The younger the patient, the more severe the manifestations of the obstruction. Differences in the presentation also depend on whether the process is acute, subacute, or chronic. The common clinical complaints include a cough, stridor or noisy breathing, difficulty breathing, and respiratory distress. The severity of the respiratory distress can range from mild to moderate or severe. Head bobbing, altered mental status, lethargy, coma, and loss of consciousness are present when the obstruction is severe and impedes breathing. This results in severe hypoxemia or hypocarbia. Initial exam findings include respiratory distress, increased work of breathing, anxiety and chest retractions. Audible stridor is usually appreciated, which worsens with agitation or crying. Wheezing is an uncommon finding with upper airway obstruction and often demonstrates lower airway or chest pathology.

Evaluation

Evaluation should include a complete assessment of the child including the respiratory distress. Work of breathing can be assessed under different categories in categorizing pediatric respiratory distress. This should include the mental status of the child, work of breathing, the use of accessory muscles, respiratory rate, pulse oximetry or end-tidal carbon dioxide monitoring, and auscultation of breath sounds. All parameters should be used in conjunction to evaluate the level of respiratory compromise in a child. Altered mental status and lethargy or fatigue without increased work of breathing or tachypnea should raise concerns for impending respiratory or cardiovascular failure.

The next step in the evaluation of the respiratory status is the assessment of the airway. Various scoring systems are available for evaluation of the airway. Commonly used systems are the Mallampatti scoring system and the ASA (American Society of Anesthesiologists). Assessment of the airway should include management interventions and correction in a step-wise management

Odynophagia may be seen in patients with abscesses of the oropharynx or hypopharynx

Treatment / Management

Management of upper airway obstruction depends on the etiology. Primary management should focus on keeping the patient calm, reducing anxiety, and getting the patient in a position of comfort. Airway, breathing, and circulation should be assessed in the primary survey. Any causes of obstruction should be relieved immediately. A foreign body in the oral cavity or upper pharynx can be removed with forceps after direct visualization. Care should be taken to avoid any interventions that may make the child anxious or irritate the child. Avoid intravenous access, painful procedures in patients with acute epiglottitis or tracheitis, to minimize respiratory distress and impending respiratory failure.[9][20]

Corticosteroids have proven to be a benefit for causes related to edema and inflammation of the upper airway in conditions like croup. Mechanism of action includes anti-inflammatory and reduction of edema. Racemic epinephrine via nebulized route has both alpha and beta action and causes upper and lower airway lumen dilation, which improves air entry and results in a more laminar airflow.

Invasive airway adjunct like oropharyngeal and nasopharyngeal airway help in relieving airway obstruction and can be used in cases of tongue edema or inflammation. Positive pressure ventilation is used for relief via bag and mask ventilation if the patient is in severe distress, has increased work of breathing and in patients en route to intubation. Endotracheal obstruction can be used if all other methods of relief are unsuccessful and the patient has an impending respiratory failure, is comatose, altered mental status, or has worsening respiratory distress.

Surgical airway with tracheostomy or cricothyroidotomy is used in rare instances when attempts to relieve upper airway obstruction fail. There are instances of facial burns or facial trauma where obtaining an upper airway adjunct or endotracheal intubation are unsuccessful. The surgical airway should be initiated by an experienced health care provider with adequate training. Best outcomes are achieved when it is initiated promptly with experienced and skilled personnel.

Enhancing Healthcare Team Outcomes

Supraglottic obstruction has many causes and can quickly turn into a life threatening emergency. The condition is best managed by a multidisciplinary team that consists of an ENT surgeon, anesthesiologist, general surgeon, an infectious disease specialist and a pulmonologist. Healthcare workers including the nurse practitioner who work in the emergency department must be aware of the condition, its presentation and management. If there is a delay in treatment, the condition can prove fatal.


References

[1] Shembel AC,Hartnick CJ,Bunting G,Ballif C,Vanswearingen J,Shaiman S,Johnson A,de Guzman V,Verdolini Abbott K, The Study of Laryngoscopic and Autonomic Patterns in Exercise-Induced Laryngeal Obstruction. The Annals of otology, rhinology, and laryngology. 2018 Nov;     [PubMed PMID: 30187760]
[2] Atanelov Z,Rebstock SE, Airway, Nasopharyngeal 2018 Jan;     [PubMed PMID: 30020592]
[3] Malpas G,Hung O,Gilchrist A,Wong C,Kent B,Hirsch GM,Hart RD, The use of extracorporeal membrane oxygenation in the anticipated difficult airway: a case report and systematic review. Canadian journal of anaesthesia = Journal canadien d'anesthesie. 2018 Jun;     [PubMed PMID: 29497994]
[4] Linscott MS,Horton WC, Management of upper airway obstruction. Otolaryngologic clinics of North America. 1979 May;     [PubMed PMID: 460879]
[5] Foncerrada G,Culnan DM,Capek KD,González-Trejo S,Cambiaso-Daniel J,Woodson LC,Herndon DN,Finnerty CC,Lee JO, Inhalation Injury in the Burned Patient. Annals of plastic surgery. 2018 Mar;     [PubMed PMID: 29461292]
[6] Kundra P,Garg R,Patwa A,Ahmed SM,Ramkumar V,Shah A,Divatia JV,Shetty SR,Raveendra US,Doctor JR,Pawar DK,Singaravelu R,Das S,Myatra SN, All India Difficult Airway Association 2016 guidelines for the management of anticipated difficult extubation. Indian journal of anaesthesia. 2016 Dec;     [PubMed PMID: 28003693]
[7] Yuan I,Bruins BB,Kiell EP,Javia LR,Galvez JA, Anesthetic Management for Pediatric Awake Tracheostomy. A     [PubMed PMID: 27669029]
[8] Wong P,Wong J,Mok MU, Anaesthetic management of acute airway obstruction. Singapore medical journal. 2016 Mar     [PubMed PMID: 26996162]
[9] Pfleger A,Eber E, Assessment and causes of stridor. Paediatric respiratory reviews. 2016 Mar;     [PubMed PMID: 26707546]
[10] Cicardi M,Bellis P,Bertazzoni G,Cancian M,Chiesa M,Cremonesi P,Marino P,Montano N,Morselli C,Ottaviani F,Perricone R,Triggiani M,Zanichelli A, Guidance for diagnosis and treatment of acute angioedema in the emergency department: consensus statement by a panel of Italian experts. Internal and emergency medicine. 2014 Feb;     [PubMed PMID: 24002787]
[11] Cielo CM,Montalva FM,Taylor JA, Craniofacial disorders associated with airway obstruction in the neonate. Seminars in fetal     [PubMed PMID: 26997148]
[12] Kusak B,Cichocka-Jarosz E,Jedynak-Wasowicz U,Lis G, Types of laryngomalacia in children: interrelationship between clinical course and comorbid conditions. European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery. 2017 Mar;     [PubMed PMID: 27722899]
[13] Knorr TL,Sinha V, Abscess, Retropharyngeal . 2019 Jan     [PubMed PMID: 28722903]
[14] Tanigawa T,Kano F,Inukai D,Kuruma T, Adult retropharyngeal abscess. IDCases. 2017     [PubMed PMID: 29159072]
[15]     [PubMed PMID: 28860869]
[16]     [PubMed PMID: 29796210]
[17]     [PubMed PMID: 10417451]
[18] ObtuÅ‚owicz K, Bradykinin-mediated angioedema. Polskie Archiwum Medycyny Wewnetrznej. 2016;     [PubMed PMID: 26842379]
[19] Bhananker SM,Posner KL,Cheney FW,Caplan RA,Lee LA,Domino KB, Injury and liability associated with monitored anesthesia care: a closed claims analysis. Anesthesiology. 2006 Feb;     [PubMed PMID: 16436839]
[20] Frerk C,Mitchell VS,McNarry AF,Mendonca C,Bhagrath R,Patel A,O'Sullivan EP,Woodall NM,Ahmad I, Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. British journal of anaesthesia. 2015 Dec;     [PubMed PMID: 26556848]