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Pulmonary aspiration

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Pulmonary aspiration
Upper gastrointestinal series at the level of the esophagus, showing pulmonary aspiration of the radiocontrast agent
SpecialtyPulmonology
CausesForeign body aspiration

Pulmonary aspiration is the entry of material such as pharyngeal secretions, food or drink, or stomach contents from the oropharynx or gastrointestinal tract, into the larynx (voice box) and lower respiratory tract, the portions of the respiratory system from the trachea (windpipe) to the lungs. A person may inhale the material, or it may be delivered into the tracheobronchial tree during positive pressure ventilation. When pulmonary aspiration occurs during eating and drinking, the aspirated material is often colloquially referred to as "going down the wrong pipe".

Consequences of pulmonary aspiration range from no injury at all, to chemical pneumonitis or pneumonia, to death within minutes from asphyxiation. These consequences depend on the volume, chemical composition, particle size, and presence of infectious agents in the aspirated material, and on the underlying health status of the person.

In healthy people, aspiration of small quantities of material is common and rarely results in disease or injury. People with significant underlying disease or injury are at greater risk for developing respiratory complications following pulmonary aspiration, especially hospitalized patients, because of certain factors such as depressed level of consciousness and impaired airway defenses (gag reflex and respiratory tract antimicrobial defense system). About 3.6 million cases of pulmonary aspiration or foreign body in the airway occurred in 2013.[1]

Causes and Risk Factors

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Neurologic Impairment

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Any condition that results in depressed level of consciousness (such as traumatic brain injury, alcohol intoxication, drug overdose, medical sedation, stroke, and general anesthesia) can result in pulmonary aspiration of pharyngeal secretions.[2] Neurologic conditions that affect muscle coordination and posture (such as cerebral palsy, Parkinson's disease, muscular dystrophies, etc.) can also increase risk of aspiration.

Pulmonary Disease

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Patients with a poor ability to clear their airway of secretions are at an increased risk of pulmonary aspiration.[3] This includes patients with pulmonary disease resulting in a weak cough, or poor forced expiratory volume. Any condition requiring mechanical ventilation is also at risk for aspiration.

Oropharyngeal Disorders

Conditions which disrupt coordination of swallowing above the glottis put a patient at increased risk for aspiration. This is referred to as oropharyngeal dysphagia and can be a result of structural abnormalities (strictures, stenosis, mediastinal and neck masses, etc.), connective tissue diseases, neuropathy, or other central nervous system-related disorders (stroke, head injury, ALS, Guillain-Barre, etc.).[4]

Medications

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Drugs can increase a person's risk of aspiration through multiple mechanisms. [5] Medications including sedatives, hypnotics, and antipsychotics can result in decreased level of consciousness and loss of cough and swallow reflexes.[6] Long-term use of proton pump inhibitors can lead to overgrowth of gastric bacteria and increase risk of aspiration.[7] Antihistamines and antidepressants can cause xerostomia (decreased oral secretions) which can also lead to aspiration.[8]

Foreign-Body Aspiration

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Particularly common in children, foreign-body aspiration occurs when an object is inhaled from the mouth into the airway. Objects commonly include food, coins, toys and balloons.[9] Age and developmental delays are therefore also considered risk factors for aspiration. The lumen of the right main bronchus is more vertical and slightly wider than that of the left, so aspirated objects are more likely to end up in this bronchus or one of its subsequent bifurcations.[10]

Complications

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Aspiration pneumonia

Aspiration Pneumonia

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Aspiration pneumonia is when bacteria is carried into the respiratory tract via aspiration and subsequently causes an infection of the lung. Any substance or object that is aspirated into the airway has the potential of carrying infectious agents with it into the respiratory tract. It primarily affects older adults and can be especially severe in patients with learning disabilities, or disorders of abnormal swallowing.[11]

Aspiration Pneumonitis

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Aspiration pneumonitis (Mendelson's syndrome) is chemical injury of lung tissue secondary to aspiration of regurtitated gastric acid.[12] The syndrome was first described among pregnant patients[13] after the administration of anesthesia, though it can occur in any scenario where gastric contents are aspirated.[14]

Histopathology of aspiration, taken from an autopsy, showing plant-like cells in a bronchiole. However, alveoli were clear, indicating a finding secondary to cardiopulmonary resuscitation rather than a primary cause of death.

Prevention

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The lungs are normally protected against aspiration by a series of protective reflexes such as coughing and swallowing. Significant aspiration can only occur if the protective reflexes are absent or severely diminished (in neurological disease, coma, drug overdose, sedation or general anesthesia). In intensive care, sitting patients up reduces the risk of pulmonary aspiration and ventilator-associated pneumonia.

Measures to prevent aspiration depend on the situation and the patient. In patients at imminent risk of aspiration, tracheal intubation by a trained health professional provides the best protection. A simpler intervention that can be implemented is to lay the patient on their side in the recovery position (as taught in first aid and CPR classes), so that any vomitus produced by the patient will drain out their mouth instead of back down their pharynx. Some anesthetists will use sodium citrate to neutralize the stomach's low pH and metoclopramide or domperidone (pro-kinetic agents) to empty the stomach. In veterinary settings, emetics may be used to empty the stomach prior to sedation. Due to growing issues with patients not complying with fasting recommendations before surgery, some hospitals will now also routinely administer emetics prior to anesthesia. Newer operating rooms are often equipped with dedicated vomitoria for this purpose.

People with chronic neurological disorders, for example, after a stroke, are less likely to aspirate thickened fluids on an instrumental swallowing assessment. However, this does not necessarily translate into reduced risk of pneumonia in real life eating and drinking.[15] Also, pharyngeal residue is more common with very thickened fluids: this may subsequently be aspirated and lead to a more severe pneumonia.[16]

The location of abscesses caused by aspiration depends on the position one is in. If one is sitting or standing up, the aspirate ends up in the posterior basal segment of the right lower lobe. If one is on one's back, it goes to the superior segment of the right lower lobe. If one is lying on the right side, it goes to the posterior segment of the right upper lobe, or the posterior basal segment of the right upper lobe. If one is lying on the left, it goes to the lingula.

Management

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See also: Choking § Treatment, Basic Life Support, Advanced Cardiovascular Life Support

Treatment of foreign body aspiration is determined by the age of the patient and the severity of obstruction of the airway involved.[17]

Basic management

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Main article: Choking § Basic treatment (first aid)

An airway obstruction can be partial or complete. In partial obstruction, the patient can usually clear the foreign body with coughing.[17] In complete obstruction, acute intervention is required to remove the foreign body.[17]

If foreign body aspiration is suspected, finger sweeping in the mouth is not recommended due to the increased risk of displacing the foreign object further into the airway.[17]

For choking children less than 1 year of age, the child should be placed face down over the rescuer's arm.[17] Back blows should be delivered with the heel of the hand, then the patient should be turned face-up and chest thrusts should be administered.[17] The rescuer should alternate five back blows followed by five chest thrusts until the object is cleared.[17] The Heimlich maneuver should be used in choking patients older than 1 year of age to dislodge a foreign body.[17] If the patient becomes unresponsive during physical intervention, cardiopulmonary resuscitation (CPR) should be started.[17]

Advanced management

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In the event that the basic measures do not remove the foreign body, and adequate ventilation cannot be restored, need for treatment by trained personnel becomes necessary.[17] Laryngoscopy should be performed in unresponsive patients if non-invasive airway clearance techniques are unsuccessful.[18] Laryngoscopy involves placing a device in the mouth to visualize the back of the airway.[18] If the foreign body can be seen, it can be removed with forceps.[18] An endotracheal tube should then be placed in order to prevent airway compromise from resulting inflammation after the procedure.[18] If the foreign body cannot be visualized, intubation, tracheotomy, or needle cricothyrotomy can be done to restore an airway for patients who have become unresponsive due to airway compromise.[17]

If non-invasive measures do not dislodge the foreign body, and the patient can maintain adequate ventilation, rigid bronchoscopy under general anesthesia should be performed.[17] Supplemental oxygen, cardiac monitoring, and a pulse oximeter should be applied to the patient.[18] Efforts should be made to keep the patient calm and avoid agitating the patient to prevent further airway compromise.[18] Flexible rather than rigid bronchoscopy might be used when the diagnosis or object location are unclear. When flexible bronchoscope is used, rigid bronchoscope is typically on standby and readily available as this is the preferred approach for removal.[19] Rigid bronchoscopy allows good airway control, ready bleeding management, better visualization, and ability to manipulate the aspirated object with a variety of forceps.[19] Flexible bronchoscopy may be used for extraction when distal access is needed and the operator is experienced in this technique.[19] Potential advantages include avoidance of general anesthesia as well as the ability to reach subsegmental bronchi which are smaller in diameter and further down the respiratory tract than the main bronchi.[19] The main disadvantage of using a flexible scope is the risk of further dislodging the object and causing airway compromise.[19] Bronchoscopy is successful in removing the foreign body in approximately 95% of cases with a complication rate of only 1%.[19]

After the foreign body is removed, patients should receive nebulized beta-adrenergic medication and chest physiotherapy to further protect the airway.[17] Steroidal anti-inflammatories and antibiotics are not routinely administered except in certain scenarios.[17] These include situations such as when the foreign body is difficult or impossible to extract, when there is a documented respiratory tract infection, and when swelling within the airway occurs after removal of the object.[19] Glucocorticoids may be administered when the foreign body is surrounded by inflamed tissue and extraction is difficult or impossible.[19] In such cases, extraction may be delayed for a short course of glucocorticoids so that the inflammation may be reduced before subsequent attempts.[19] These patients should remain under observation in the hospital until successful extraction as this practice can result in dislodgement of the foreign body.[19] Antibiotics are appropriate when an infection has developed but should not delay extraction.[19] In fact, removal of the object may improve infection control by removing the infectious source as well as using cultures taken during the bronchoscopy to guide antibiotic choice.[19] When airway edema or swelling occur, the patient may have stridor. In these cases, glucocorticoids, aerosolized epinephrine, or helium oxygen therapy may be considered as part of the management plan.[19]

Patients who are clinically stable with no need for supplemental oxygen after extraction may be discharged from the hospital the same day as the procedure.[20] Routine imaging such as a follow-up chest x-ray are not needed unless symptoms persist or worsen, or if the patient had imaging abnormalities previously to verify return to normal.[20] Most children are discharged within 24 hours of the procedure.[21]

See also

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References

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  1. ^ Vos, Theo; Barber, Ryan M; Bell, Brad; Bertozzi-Villa, Amelia; Biryukov, Stan; Bolliger, Ian; Charlson, Fiona; Davis, Adrian; Degenhardt, Louisa; Dicker, Daniel; Duan, Leilei; Erskine, Holly; Feigin, Valery L; Ferrari, Alize J; Fitzmaurice, Christina; Fleming, Thomas; Graetz, Nicholas; Guinovart, Caterina; Haagsma, Juanita; Hansen, Gillian M; Hanson, Sarah Wulf; Heuton, Kyle R; Higashi, Hideki; Kassebaum, Nicholas; Kyu, Hmwe; Laurie, Evan; Liang, Xiofeng; Lofgren, Katherine; Lozano, Rafael; et al. (2015). "Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: A systematic analysis for the Global Burden of Disease Study 2013". The Lancet. 386 (9995): 743–800. doi:10.1016/s0140-6736(15)60692-4. PMC 4561509. PMID 26063472.
  2. ^ Huxley, Eliot J.; Viroslav, Jose; Gray, William R.; Pierce, Alan K. (1978). "Pharyngeal aspiration in normal adults and patients with depressed consciousness". The American Journal of Medicine. 64 (4): 564–8. doi:10.1016/0002-9343(78)90574-0. PMID 645722.
  3. ^ Ficke, Benjamin; Rajasurya, Venkat; Sanghavi, Devang K.; Cascella, Marco (2024), "Chronic Aspiration", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 32809569, retrieved 10 November 2024
  4. ^ Fernández-Carmona, A.; Peñas-Maldonado, L.; Yuste-Osorio, E.; Díaz-Redondo, A. (1 August 2012). "Exploration and approach to artificial airway dysphagia". Medicina Intensiva (English Edition). 36 (6): 423–433. doi:10.1016/j.medine.2012.09.001. ISSN 2173-5727. PMID 22055775.
  5. ^ Gonçalves-Pereira, João; Mergulhão, Paulo; Froes, Filipe (25 October 2024). "Medications to Modify Aspiration Risk: Those That Add to Risk and Those That May Reduce Risk". Seminars in Respiratory and Critical Care Medicine. doi:10.1055/s-0044-1791827. ISSN 1098-9048. PMID 39454640.
  6. ^ Meeusen, Vera; Barach, Paul; van Zundert, André (1 January 2024), Sanchez, Juan A.; Higgins, Robert S. D.; Kent, Paula S. (eds.), "Chapter 10 - Designing safe procedural sedation: adopting a resilient culture", Handbook of Perioperative and Procedural Patient Safety, Elsevier, pp. 115–163, ISBN 978-0-323-66179-9, retrieved 10 November 2024
  7. ^ Fohl, Alexander L (2011). "Proton pump inhibitor-associated pneumonia: Not a breath of fresh air after all?". World Journal of Gastrointestinal Pharmacology and Therapeutics. 2 (3): 17–26. doi:10.4292/wjgpt.v2.i3.17. ISSN 2150-5349. PMC 3124633. PMID 21731913.
  8. ^ Ficke, Benjamin; Rajasurya, Venkat; Sanghavi, Devang K.; Cascella, Marco (2024), "Chronic Aspiration", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 32809569, retrieved 10 November 2024
  9. ^ Cramer, Natan; Jabbour, Noel; Tavarez, Melissa M.; Taylor, Roger S. (2024), "Foreign Body Aspiration", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 30285375, retrieved 10 November 2024
  10. ^ Al Shamrani, Abdullah; AlShammari, Ayshah; AlAlkami, Halima; AlShanwani, Jawaher; Alharbi, Adel S. (1 December 2021). "When is asthma not guilty?". International Journal of Pediatrics and Adolescent Medicine. 8 (4): 203–211. doi:10.1016/j.ijpam.2020.10.002. ISSN 2352-6467. PMC 8356124. PMID 34401444.
  11. ^ Sanivarapu, Raghavendra R.; Vaqar, Sarosh; Gibson, Joshua (2024), "Aspiration Pneumonia", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 29261921, retrieved 12 November 2024
  12. ^ Marik, Paul E. (March 2001). "Aspiration Pneumonitis and Aspiration Pneumonia". New England Journal of Medicine. 344 (9): 665–671. doi:10.1056/NEJM200103013440908. ISSN 0028-4793. PMID 11228282.
  13. ^ Mendelson, C. L. (August 1946). "The aspiration of stomach contents into the lungs during obstetric anesthesia". American Journal of Obstetrics and Gynecology. 52 (2): 191–205. doi:10.1016/s0002-9378(16)39829-5. ISSN 0002-9378. PMID 20993766.
  14. ^ Marik, Paul E (May 2011). "Pulmonary aspiration syndromes". Current Opinion in Pulmonary Medicine. 17 (3): 148–154. doi:10.1097/MCP.0b013e32834397d6. ISSN 1070-5287. PMID 21311332.
  15. ^ O'Keeffe ST. (July 2018). Use of modified diets to prevent aspiration in oropharyngeal dysphagia: is current practice justified? BMC Geriatrics. 2018;18:167 https://doi.org/10.1186/s12877-018-0839-7
  16. ^ Robbins J, Gensler G, Hind J, Logemann JA, Lindblad AS, Brandt D, et al. Comparison of 2 interventions for fluid aspiration on pneumonia incidence: a randomised trial. Ann Intern Med. 2008;148:509–18.
  17. ^ a b c d e f g h i j k l m n Federico, Monica (2018). Current Diagnosis & Treatment: Pediatrics, 24e, "Respiratory Tract & Mediastinum". New York, NY: McGraw-Hill. ISBN 978-1259862908.
  18. ^ a b c d e f Lucia, Dominic (2017). Current Diagnosis & Treatment: Emergency Medicine, 8e, "Respiratory Distress". New York, NY: McGraw-Hill. ISBN 978-0071840613.
  19. ^ a b c d e f g h i j k l m Sheperd, Wes (2019). Airway foreign bodies in adults. In: UpToDate, Post, TW (Ed), UpToDate, Waltham, MA.
  20. ^ a b EBSCO Informational Services (2020). "Foreign Body Aspiration". DynaMed. Retrieved 2 November 2020.
  21. ^ Rovin, J. D.; Rodgers, B. M. (1 March 2000). "Pediatric Foreign Body Aspiration". Pediatrics in Review. 21 (3): 86–90. doi:10.1542/pir.21-3-86. ISSN 0191-9601. PMID 10702322. S2CID 40614870.

Further reading

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