Airway obstruction
| Airway obstruction | |
|---|---|
| Specialty | Pulmonology  |
Airway obstruction is a blockage of respiration in the airway that hinders the free flow of air. Airway obstructions can occur either in the upper airway (UPA) or lower airway (LOA). The upper airway consists of the nose, throat, and larynx. The lower airway comprises the trachea, bronchi, and bronchioles. [1]
Airway obstruction is a life-threatening condition and requires urgent attention, and assistance when it is needed.[2]
Upper airway obstruction
[edit]Causes
[edit]The causes of upper airway obstructions can be acute or chronic. More acute causes of upper airway obstruction include foreign body aspiration, blunt trauma to the neck, infections, and swelling due to allergies or other inflammatory conditions.[3] In children, viral infections such as croup or epiglottitis are frequent causes.[4] Adults are more likely to experience obstruction from enlargement of the tonsils or vocal cord paralysis. [3] Obstructive sleep apnea is the most common chronic cause of upper airway obstruction.[2]
Symptoms
[edit]It is possible to determine where the obstruction is based on the patient's symptoms. Stridor is a high-pitched sound which occurs during breathing and is associated with obstruction at the level of the larynx. Difficulty swallowing and changes in voice are also common symptoms.[3] If there is total obstruction, severe respiratory distress or cyanosis due to hypoxia (lack of oxygen in the blood) can occur.[2]
Diagnosis
[edit]
It is crucial to determine if a patient has an acute upper airway obstruction. Respiratory distress can rapidly lead to respiratory failure without appropriate management.[2] Thus, the first step is to conduct an urgent and comprehensive assessment of ABCs (airway, breathing, and circulation).[1]
Imaging studies can also help with diagnosis. First-line imaging studies include x-rays and CT scans. They can quickly assess the obstruction's extent.[2] For children, ultrasound or MRI are preferred as they do not involve radiation.[5] Flexible laryngoscopy or bronchoscopy can directly visualize the airway.[2]
Management
[edit]Treatment depends on how severe the patient's condition is and the cause of the obstruction.
If the patient is choking on a foreign body, the Heimlich maneuver should be initiated. More invasive methods, such as intubation, may be necessary to secure the airway. In severe cases, intubation may be difficult. Thus, a cricothyrotomy or tracheostomy may be necessary.[2]
Infections typically cause obstruction by swelling. So, they are usually treated with antibiotics or corticosteroids to reduce inflammation.[1] For causes like tumors or abscesses, surgical intervention may be required for removal. [2]
Prognosis and Outcomes
[edit]The prognosis depends on the cause and rapidity of intervention. With prompt treatment, outcomes are usually favorable. This is especially true for reversible conditions, like foreign body aspiration.[2] Chronic conditions, like vocal cord paralysis and sleep apnea,[6] may need ongoing care. If managed well, they usually have good outcomes.
Lower airway obstruction
[edit]Lower airway obstruction is mainly caused by increased resistance in the bronchioles (usually from a decreased radius of the bronchioles) that reduces the amount of air inhaled in each breath and the oxygen that reaches the pulmonary arteries. It is different from airway restriction (which prevents air from diffusing into the pulmonary arteries because of some kind of blockage in the lungs). Diseases that cause lower airway obstruction are termed obstructive lung diseases.[7]
Lower airway obstruction can be measured using spirometry. A decreased FEV1/FVC ratio (versus the normal of about 80%) is indicative of airway obstruction, as the normal amount of air can no longer be exhaled in the first second of expiration. An airway restriction would not produce a reduced FEV1/FVC ratio, but would reduce the vital capacity. The ventilation is therefore affected leading to a ventilation-perfusion mismatch and hypoxia.
Complications
[edit]Airway obstruction may cause obstructive pneumonitis or post-obstructive pneumonitis. It can also be a sign of chronic obstructive pulmonary disease (COPD), a common breathing disorder that is a risk factor for lung cancer.[8][9]
See also
[edit]References
[edit]- ^ a b c Loscalzo, Joseph; Fauci, Anthony; Kasper, Dennis; Hauser, Stephen; Longo, Dan; Jameson, Larry (2022). Harrison's Principles of Internal Medicine (21 ed.). McGraw Hill Education.
- ^ a b c d e f g h i Aboussouan, L.S.; Stoller, J.K (15 March 1994). "Diagnosis and management of upper airway obstruction". Clinics in Chest Medicine. 15 (1): 35–53. doi:10.1016/S0272-5231(21)01054-6. PMID 8200192. Archived from the original on 25 June 2021. Retrieved 25 June 2021.
- ^ a b c O Cathain, Eadaoin; Gaffey, Megan M. (2024), "Upper Airway Obstruction", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 33232069, retrieved 2024-10-31
- ^ Johnson, David Wyatt (2014-09-29). "Croup". BMJ Clinical Evidence. 2014: 0321. ISSN 1752-8526. PMC 4178284. PMID 25263284.
- ^ Ohana, Orly; Soffer, Shelly; Zimlichman, Eyal; Klang, Eyal (2018-05-01). "Overuse of CT and MRI in paediatric emergency departments". The British Journal of Radiology. 91 (1085). doi:10.1259/bjr.20170434. ISSN 0007-1285. PMC 6190788. PMID 29271231.
- ^ Patil, Susheel P.; Ayappa, Indu A.; Caples, Sean M.; Kimoff, R. John; Patel, Sanjay R.; Harrod, Christopher G. (2019-02-15). "Treatment of Adult Obstructive Sleep Apnea With Positive Airway Pressure: An American Academy of Sleep Medicine Systematic Review, Meta-Analysis, and GRADE Assessment". Journal of Clinical Sleep Medicine. 15 (2): 301–334. doi:10.5664/jcsm.7638. ISSN 1550-9389. PMC 6374080. PMID 30736888.
- ^ "Airway Obstruction". The Lecturio Medical Concept Library. Archived from the original on 2021-06-25. Retrieved 2021-06-25.
- ^ "Lung health checks in supermarket car parks reach older smokers in deprived communities". NIHR Evidence (Plain English summary). 2020-08-05. doi:10.3310/alert_40661. S2CID 243394660. Archived from the original on 2022-03-14. Retrieved 2024-07-01.
- ^ Balata, Haval; Harvey, Jonathan; Barber, Phil V; Colligan, Denis; Duerden, Rebecca; Elton, Peter; Evison, Matthew; Greaves, Melanie; Howells, John; Irion, Klaus; Karunaratne, Devinda (15 Jul 2020). "Spirometry performed as part of the Manchester community-based lung cancer screening programme detects a high prevalence of airflow obstruction in individuals without a prior diagnosis of COPD". Thorax. 75 (8): 655–660. doi:10.1136/thoraxjnl-2019-213584. ISSN 0040-6376. PMID 32444437. S2CID 218855570.