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FACT SHEET: Aspiration and Aspiration Syndromes (Foreign Body Aspiration and Aspiration Pneumonia)1: (aspiration is also known as “airway aspiration” and “pulmonary aspiration”; aspiration pneumonia is also known as “AP”, “anaerobic pneumonia”2, and “necrotizing pneumonia”)

Date of Publication: January 22, 2024

Note: Pneumonia is broadly addressed (with an emphasis on non-aspiration forms) in a separate fact sheet.

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • Yes, in the case of foreign body airway obstruction (FBAO).
  • Yes, in the case of acute foreign body aspiration (which can lead to FBAO).
  • Possibly, in the case of chronic foreign body aspiration, if the patient/client is medically unstable or has significant complications.
  • Yes, in the case of aspiration pneumonia, if the patient/client has active disease and/or is contagious. (Depending on its specific microbial etiology and underlying patient/client-specific factors, aspiration pneumonia may be less contagious than other forms of pneumonia.)

Is medical consult advised?

  • Yes, if patient/client exhibits signs/symptoms of acute foreign body aspiration.
  • Yes, if patient/client exhibits signs/symptoms of chronic foreign body aspiration.
  • Yes, if patient/client exhibits signs/symptoms of aspiration pneumonia. Referral to primary care medical provider (e.g., physician or nurse practitioner) for definitive diagnosis (clinical +/- imaging +/- laboratory) and management is indicated.
  • Possibly, if patient/client has an underlying condition(s) that elevates risk of aspiration. A medical consultation can help inform dental hygiene management.

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • Yes, in the case of foreign body airway obstruction (FBAO).
  • Yes, in the case of acute foreign body aspiration (which can lead to FBAO).
  • Possibly, in the case of chronic foreign body aspiration, if the patient/client is medically unstable or has significant complications.
  • Yes, in the case of aspiration pneumonia, if the patient/client has active disease and/or is contagious. (Depending on its specific microbial etiology and underlying patient/client-specific factors, aspiration pneumonia may be less contagious than other forms of pneumonia.)

Is medical consult advised?

  • See above.

Is medical clearance required?

  • Yes, potentially for patients/clients at substantially elevated risk of aspiration in the dental hygiene operatory setting.
  • Yes, to ensure patients/clients with pre-existing aspiration syndromes have been adequately treated and are medically stable.
  • Yes, following foreign body aspiration occurring in the dental hygiene operatory setting.

Is antibiotic prophylaxis required?

  • No (although antibiotics may be required for treatment of bacterial pneumonia).

Is postponing treatment advised?

  • Yes, if the patient/client presents with foreign body airway obstruction or if FBAO occurs in the dental/dental hygiene office. FBAO must be recognized and managed quickly in order to avoid complete upper airway obstruction, which constitutes a life-threatening medical emergency. Prompt management of FBAO will also decrease the chance of further aspiration of the foreign body into the lungs.
  • Yes, until acute foreign body aspiration is resolved and the patient/client is medically stable.
  • Possibly, dependent on symptomatology and potential complications of chronic foreign body aspiration.
  • Yes, if patient/client has pneumonia, of aspiration etiology or otherwise. Ideally, the patient/client should be treated for the pneumonia before undergoing elective procedures.

Oral management implications

  • The dental hygienist needs to address aspiration from two over-arching imperatives:
    • recognition and management of pre-existing aspiration syndromes in the patient/client presenting to the dental hygiene operatory; and, perhaps even more critically,
    • prevention and management of aspiration occurring during dental hygiene procedures, including, in particular, foreign body airway obstruction.

Both imperatives involve identifying patients/clients at elevated risk of aspiration.

  • Recurrent aspiration due to underlying medical or neurological conditions can be difficult to manage, and input and care from a multidisciplinary team is likely warranted.
  • Aspiration is more common in patients/clients who have had dental procedures or general anaesthesia, especially in combination with other risk factors.
  • In the dental/dental hygiene office setting, pieces of debris, inlays, alloy, or burrs can fall into the oropharynx of the patient/client and subsequently be aspirated.
  • Reasonable preventive measures should be taken in the dental hygiene operatory to reduce the risk of aspiration of foreign bodies and other substances.3
  • To reduce risk of aspiration in patients/clients with dysphagia, the dental operatory chair should be tilted no more than 45 degrees (i.e., avoid the supine position). Because dysphagic patients/clients may be unable to manage oral fluids safely, use of water spray should be tempered.4 Adequate suction and saliva evacuation during treatment prevent fluid accumulation. Manual scaling of teeth with hand instruments (and manual dental caries removal) should be considered, as should using impression materials of optimal volume and viscosity (i.e., non-runny). After dental/dental hygiene procedures, dysphagic patients/clients should be advised to monitor for signs/symptoms of aspiration pneumonia.
  • Some persons with dysphagia have decreased neurosensory perception that impedes the protective coughing reflex.
  • Specialized dental prostheses (e.g., palatal lift appliance) can be devised to facilitate swallowing for, and reduce risk of food aspiration in, patients/clients with oral dysphagia. In patients/clients with palatal defect due to cancer resection, a speech bulb prosthesis can reduce nasal regurgitation.
  • Referral to a speech pathologist may benefit patients/clients with dysphagia. Instruction in swallowing techniques (e.g., chin-tuck strategy) can be beneficial in reducing occurrence of aspiration.
  • Patients/clients at risk of food aspiration may benefit from adoption of a diet with food textures that are less likely to be aspirated (including thickened fluids).
  • In addition to education of, and training for, the patient/client at elevated risk of aspiration, the patient/client’s caregiver, as applicable, should be educated on aspiration reduction techniques (as well as in the provision of robust oral healthcare).
  • In conscious dental/dental patients/clients, an object lost in the pharynx is likely to be recovered after coughing or swallowed into the esophagus. Thus, the actual incidence of acute airway obstruction or aspiration into the trachea, bronchial tree, or lungs is low. Furthermore, it is probable that any object entering the airway will be small enough to pass through the larynx5 and down the trachea6 without causing an obstruction.7 Nonetheless, an aspirated foreign body can become lodged in the larynx and completely block the trachea, which constitutes a medical emergency.

Acute Foreign Body Aspiration

  • Airway obstruction (FBAO) resulting from acute foreign body aspiration (or otherwise8) must be recognized and managed quickly by the oral health professional given its sudden and potentially fatal nature.
  • Invasive — and non-invasive — procedures should not be undertaken in the event of acute foreign body aspiration, and they are absolutely contraindicated in the event of foreign body airway obstruction.
  • The approach to the patient/client with FBAO consists of:
    • recognition of obstruction (partial or complete);
    • permitting the patient/client with partial airway obstruction and good air exchange to continue coughing and breathing without any direct physical intervention by rescuers9;
    • in the case of complete airway obstruction or poor air exchange in a conscious patient/client, use of nonsurgical maneuvers to relieve obstruction (i.e., Heimlich maneuver [upper abdominal thrusts], chest thrusts, or back blows10, as situationally appropriate) until object is cleared and breathing is re-established, or until patient becomes unconscious);
    • activation of EMS with 911 call; and
    • in the case of an unconscious or unresponsive patient/client with no pulse, initiation and continuation of cardiopulmonary resuscitation (CPR)11 until EMS arrives or spontaneous breathing and circulation resume.12

Chronic Foreign Body Aspiration

  • Even in non-emergency situations, expeditious removal of tracheobronchial foreign bodies is important. This reduces risk of complications from chronic foreign body aspiration. Medical intervention is required for imaging and bronchoscopy.

Aspiration Pneumonia

  • Risk of aspiration pneumonia is heightened when periodontal disease, poor oral hygiene, and dental caries are compounded by swallowing and feeding problems.
  • Aspiration pneumonia is most common among patients/clients who have dysphagia (difficulty in swallowing), and the elderly13 are particularly prone to AP.
  • While aspiration leading to pneumonia can occur at any time, it may occur in dental facilities as a result of any oral procedure or analgesia of the pharynx. In addition to saliva, blood, and debris from scaling, small objects such as inlays, alloy, burrs, or other debris can fall into the oropharynx of a patient/client and subsequently be aspirated or ingested.14
  • Proper oral care helps prevent aspiration pneumonia. Increased loads of oral biofilm are associated with hospital-acquired pneumonia and ventilator-associated pneumonia. Professional oral hygiene helps reduce the number of pathogens (including, situationally, certain bacteria and Candida albicans) in the mouth that can cause aspiration pneumonia.15
  • To reduce the risk of aspiration pneumonia, scrupulous oral hygiene should be a part of routine care for persons who have difficulty swallowing, are hospitalized, and/or are on a ventilator. Similarly, proper oral care (assisted as need be) is important for elderly persons, frail patients/clients, and residents of nursing homes, who are often unable to carry out proper self-care. For more detail, refer to the Pneumonia Fact Sheet.

Oral manifestations

  • In adults, poor dentition elevates risk of aspiration.
  • In children aged 1 to 3 years, incomplete chewing with incisors before the molars erupt may propel fragments posteriorly, triggering a reflex inhalation.
  • Anatomic irregularities of the oropharynx (e.g., cleft palate) elevate risk of aspiration.

Acute Foreign Body Aspiration

  • Cyanosis of the lips and oral mucosa may occur in patients/clients with poor air exchange.

Chronic Foreign Body Aspiration

  • Halitosis may occur.

Aspiration Pneumonia

  • Halitosis may occur.
  • The teeth and periodontium may serve as reservoirs for respiratory tract infection.
  • Aspiration of oral microorganisms that are associated with AP can occur from inhalation of saliva, vomit, food, or drink from the mouth into the lungs.
  • Poor oral hygiene elevates a patient/client’s risk of developing pneumonia from aspirated material.

Related signs and symptoms

  • Aspiration is the inhalation into the respiratory tract16 of non-air substances, typically from misdirection of oropharyngeal or gastric contents.17 Aspirated non-air substances include saliva, blood, products of dental manipulation, food18, drink, vomit19, medications, and foreign objects20. Aspiration into the larynx or trachea — particularly of vomit and foreign objects — can cause airway obstruction leading to death. Aspirated material that proceeds into the bronchial tree and lung alveoli can result in pneumonia, pneumonitis, or abscesses.
  • Aspiration, particularly of food and drink (“went down the wrong pipe”), is common. Most persons succeed in coughing up the offending substance before significant airway obstruction or other sequelae (e.g., pneumonia) ensue. However, in others, particularly those without a robust cough reflex, aspiration can cause significant morbidity or even death.
  • The timing of a macroaspiration21 event can usually be pinpointed in time. However, aspiration can also initially occur in an occult fashion (i.e., lacking overt signs/symptoms), particularly in persons with certain co-morbid conditions.
  • Aspiration syndromes include all conditions in which non-air substances are inhaled into the lungs, as well as foreign body aspiration (which may be confined to the laryngeal area). Most frequently, aspiration syndromes involve oral or gastric contents associated with gastroesophageal reflux , swallowing dysfunction, neurological disorders, and structural abnormalities. When reflux volume is significant, signs/symptoms usually manifest acutely due to penetration of gastric contents into respiratory tract; conversely, episodic incidents of small amounts of gastric reflux or saliva or other oral contents that enter the lower airways cause intermittent or persistent signs/symptoms.
  • Signs/symptoms of aspiration usually start quickly, in seconds to minutes to hours after inhalation of non-air substances, depending on degree of airway blockage, volume and toxicity of aspirated substance, and patient-specific factors. (See below for specific manifestations of the aspiration syndromes.)
  • Stridor22 and hoarse voice can result from chronic inflammation of the larynx and subglottic space due to recurrent aspiration of stomach contents.
  • Risk factors for aspiration or aspiration pneumonia include:
    • supraglottic disease (e.g., disease states – such as amyotrophic lateral sclerosis [ALS], Parkinson’s disease, and multiple sclerosis – that cause esophageal dysmotility and dysphagia [impaired swallowing] and/or difficulty in coughing, in addition to oropharynx irregularities);
    • pulmonary disease (e.g., poor cough, poor forced expiratory volume, and mechanical ventilation);
    • cognitive neurologic impairment (e.g., stroke, seizure, drug or alcohol intoxication, developmental delay, and dementia);
    • focal neurologic impairment (e.g., stroke, cerebral palsy, cranial nerve injury, and pharyngeal injury);
    • obstructive sleep apnea (which is a risk factor for aspiration of gastric contents);
    • mechanical causes (e.g., nasogastric tube, tracheostomy, bronchoscopy, upper endoscopy, and gastrotomy feeding tube); and
    • other causes (e.g., position changes23; frequent, high-volume vomiting24; proton pump inhibition25; analgesia of the pharynx and/or larynx; general anaesthesia; oral, esophageal, or airway procedures; and maxillofacial trauma).
  • Chronic lung disease may develop from repeated aspiration of refluxate. This includes, with bracketed signs/symptoms:
    • chronic bronchitis (frequent cough often productive of sputum; wheezing; chest tightness; and shortness of breath, especially with exertion);
    • pulmonary fibrosis26 (dry, hacking cough; shortness of breath, especially with exertion; rapid, shallow breathing; fatigue; unintended weight loss; and clubbing27 of fingers or toes), and
    • bronchiectasis28 (persistent cough usually productive of sputum, as well as shortness of breath).

Acute Foreign Body Aspiration

  • An aspirated foreign body may lodge in the larynx or trachea. If the solid or semi-solid object is large enough to cause complete or nearly complete obstruction of the airway, asphyxia may rapidly lead to death. Lesser degrees of obstruction or passage of the foreign body beyond the carina29 of the trachea can result in less severe signs and symptoms.
  • Signs/symptoms of acute foreign body aspiration (without necessarily significant airway obstruction) include neck/throat pain and cough.
  • Signs/symptoms of partial airway obstruction include30:
    • persons with good air exchange:
      • ability to breathe;
      • forceful cough;
      • wheezing between coughs; and
      • stridor.
    • persons with poor air exchange:
      • weak cough;
      • “crowing” sound on inspiration;
      • paradoxical respirations with poor air movement;
      • absent or altered voice sounds;
      • possible cyanosis; and
      • possible disorientation and lethargy.
  • Signs/symptoms of complete airway obstruction include31:
    • first phase while conscious (1–3 minutes):
      • inability to breathe, with paradoxical respirations without air movement;
      • aphonia (inability to speak or make sounds);
      • inability to cough;
      • universal choking sign (i.e., clutching of the neck);
      • supraclavicular and intercostal retractions;
      • panic and struggling; and
      • increased heart rate and elevated blood pressure.
    • second phase (2–5 minutes):
      • loss of consciousness; and
      • decreased respirations, heart rate, and blood pressure;
    • third phase leading to cardiorespiratory arrest and death if obstruction not relieved or airway re-established (>4–5 minutes):
      • absent vital signs;
      • coma; and
      • dilated pupils.

Chronic Foreign Body Aspiration

  • Chronic debilitating signs/symptoms with recurrent infections might occur with delayed extraction of a foreign body, or the patient/client may remain asymptomatic.
  • Signs/symptoms of chronic foreign body aspiration32 include:
    • neck/throat pain;
    • cough;
    • choking;
    • dyspnea;
    • hemoptysis (coughing up blood);
    • wheezing;
    • asymmetric lung sounds; and
    • fever.

Aspiration Pneumonia

  • AP is a type of pneumonia that occurs when something other than air is inhaled into the lungs33, and infection and inflammation result34. It typically occurs after a macroaspiration event.
  • Aspiration pneumonia accounts for 5% to 15% of community-acquired pneumonias, and a significant proportion of hospital-acquired pneumonia.
  • The right lower lobe is the most common site for AP due to the vertical orientation of the right main bronchus.
  • AP is most often associated with the elderly, particularly those who are frail, live in nursing homes, and/or have other conditions that impair the ability to swallow.
  • Aspiration leading to pneumonia can occur in any setting, but is particularly common in healthcare settings, including hospitals and long-term care facilities.
  • While signs/symptoms of aspiration often start quickly, sign/symptoms of resultant pneumonia may not manifest for several days.
  • Signs/symptoms of aspiration pneumonia include:
    • dyspnea;
    • wheezing;
    • hemoptysis (blood often mixed with mucus or saliva);
    • chest pain; and
    • fatigue.
  • Risk factors for pneumonia following aspiration include:
    • innate immunodeficiency (e.g., immunodeficiency diseases or underdeveloped immune systems, as in children younger than 5 years old);
    • immunosuppression due to diseases or their treatment; and
    • malnutrition.
  • The death rate from aspiration pneumonia is more than twice that of other pneumonias.

References and sources of more detailed information

Date: January 13, 2024


1 In addition to foreign body aspiration (acute and chronic) and aspiration pneumonia, aspiration syndromes include aspiration pneumonitis (also known as chemical pneumonitis, and briefly referenced in this Fact Sheet), lung abscess, and empyema (pus-filled pockets in the pleural space surrounding the lungs).
2 “Anaerobic pneumonia” is really a misnomer. Early microbiologic studies implicated anaerobic bacteria as causally predominant in aspiration pneumonia. However, more recent data reveals a predominance of aerobic microbes, both in community and hospital settings. Bacteria in both categories are found in the oral cavity and the oropharynx.
3 In dentistry, two major preventive measures are use of a rubber dam and oral packing.
4 Oral healthcare professionals should understand their dysphagic patient/client’s need for fluid and dietary modifications at home, such as changing thickness of beverages and limiting bolus size. This helps guide the use of fluids during dental/dental hygiene procedures. For example, a person who can only handle teaspoon amounts of fluid at home may not tolerate the use of water spray. Similarly, a patient/client who requires thicker consistency fluid for drinking is at higher risk of aspiration.
5 In adults, the larynx is the narrowest portion of the upper airway.
6 Foreign bodies that pass through the larynx and trachea will come to rest in one of the main-stem bronchi or in smaller bronchioles of the lungs.
7 Although a life-threatening situation does not immediately exist in these circumstances, the foreign object does need to be removed promptly to avoid serious sequelae such as pneumonia, other infections, or atelectasis (deflation of alveoli resulting in collapse of part, or all of, a lung). Prompt medical referral (likely to a hospital emergency department) is necessary for consultation with a radiologist (for radiographs to determine location of the foreign body), likely followed by bronchoscopy (often by a respirologist) to visualize and retrieve the foreign body.
8 Other causes of acute airway obstruction include: tonsillitis, acute epiglottis, retropharyngeal abscesses, Ludwig’s angina (diffuse cellulitis of the floor of the mouth), trauma, tumours, hematomas, congenital structural abnormalities of the airway, vocal cord pathology (such as laryngospasm and paralysis), inflammatory processes (such as thermal burns and ingestion of toxins and corrosives), anaphylaxis, angioedema, and sleep apnea. Upper airway obstruction by the tongue is the most common cause of acute airway obstruction.
9 The patient/client should be kept standing or sitting leaning forward. Ask “Can you speak?” or “Are you choking?”. Need for help may be indicated by the universal choking sign (clutching hands wrapped around neck) or by nodding.
10 Back blows/slaps, rather than abdominal thrusts, should be used in infants younger than 1 year old. Chest thrusts are indicated in pregnant or obese persons.
11 The unconscious patient/client should be placed in the supine position. Chest compressions may provide pressure to dislodge a foreign object. Quick, upward abdominal thrusts may also open the airway. Each time the airway is opened, the rescuer should look for an object in the patient/client’s mouth and remove it if found (finger sweep).
12 In the dental hygiene office setting, establishment of an emergency surgical airway (i.e., cricothyrotomy) is unlikely to be an option.
13 As age advances (and anatomical and physiological changes related to swallowing biomechanics accumulate), the speed and ease of swallowing decreases. More time is required for oral preparation of food into a bolus, which leads to decreased timeliness of swallowing function. In addition, there is an increase in post-swallow residue and penetration of swallowed material within the upper airway. Advancing age also contributes to decreases in taste, smell, and oral moisture, which can further affect swallowing physiology.
14 Foreign bodies or substances can be ingested into the gastrointestinal (GI) tract or aspirated into the respiratory tract.
15 The microbes usually associated with aspiration pneumonia are bacteria, and treatment typically involves antibiotics. Refer to Pneumonia Fact Sheet for further details.
16 Aspiration is often defined as being inhalation of non-air substances below the true vocal folds of the larynx into the lower respiratory tract. However, the term “foreign body aspiration” in the context of airway obstruction sometimes additionally encompasses the oral cavity and pharynx.
17 Aspiration may occur when non-air substances enter the hypopharynx either before relaxation of the cricopharyngeal muscle (i.e., upper esophageal sphincter) or before closing of the laryngeal sphincters.
18 Direct aspiration of food is the aspiration of a food bolus while swallowing, whereas indirect aspiration is the reflux of food from the stomach into the esophagus and hence the respiratory tract.
19 Vomit is one of the most common causes of aspiration pneumonia, particularly in persons who are unconscious or semi-conscious.
20 Commonly aspirated objects include seeds, nuts, bone fragments, coins, nails, small toys, pins, medical instrument fragments, and dental appliances. Geographic differences affect the spectrum of objects aspirated, as does age of the person who aspirates.
21 Microaspiration is normal in healthy people, and it contributes to most causes of pneumonia.
22 Stridor is an abnormal, high-pitched respiratory sound produced by irregular airflow in a narrowed airway.
23 Position changes can lead to aspiration even in healthy patients/clients. About 50% of persons have silent aspiration during sleep, although most such persons do not subsequently develop clinically relevant pneumonia.
24 Such vomiting can occur as a result of many conditions, including bulimia and pregnancy (i.e., severe “morning sickness”).
25 Proton pump inhibitors (which are used in the management of gastroesophageal reflux disease [GERD] and peptic [stomach and duodenal intestine] ulcers) raise gastric pH, thereby allowing overgrowth of potentially harmful microorganisms in the stomach.
26 Pulmonary fibrosis may occur over time due to repeated aspiration of small volumes of gastric secretions, which leads to a progressive fibrotic response in the lungs.
27 Clubbing is widening and rounding of the tips of the fingers or toes.
28 Bronchiectasis is a long-term condition in which the airways of the lungs become widened, leading to a build-up of excess mucus that makes the lungs more vulnerable to infection.
29 The carina is a ridge of cartilage at the bottom of the trachea at the bifurcation of the left and right main bronchi.
30 modified from Box 11.6, p. 191 in Malamed SF. Medical Emergencies in the Dental Office (8th edition). St. Louis: Elsevier; 2023.
31 modified from Table 11.3, p. 190 in Malamed SF. Medical Emergencies in the Dental Office (8th edition). St. Louis: Elsevier; 2023.
32 In contrast to chronic foreign body aspiration (i.e., respiratory tract involvement), signs/symptoms of chronic foreign body ingestion (i.e., gastrointestinal tract involvement) include: fever, vomiting, hematemesis (vomiting of blood), abdominal pain/distention/tenderness/guarding, chest pain, hematochezia (passage of fresh blood from the anus), weight loss, and food refusal. Although 90% of swallowed foreign objects that successfully pass through the esophagus continue through the gastrointestinal (GI) tract (and are defecated) without significant morbidity, complications include: GI blockages, GI perforations, peritonitis, and peritoneal abscesses.
33 Aspiration pneumonitis is inhalational injury results from the same non-air inhalation as aspiration pneumonia, but inflammation and irritation occur without infection. Typically, aspiration pneumonitis results from inhalation of sterile gastric contents, whereas aspiration pneumonia is characterized by aspiration of colonized oropharyngeal material. Signs/symptoms of aspiration pneumonitis are often similar to those of aspiration pneumonia, and they include: dyspnea (shortness of breath) and cough (both of which may occur within minutes or hours after inhalation of a toxic substance); fever; and pink, frothy sputum. Pneumonia can be considered a type of pneumonitis – one that involves microbes. Furthermore, bacterial pneumonia can often develop as a complication of aspiration (chemical) pneumonitis.
34 Aspiration of bacteria leads to infection and pneumonia in some persons but not others. A combination of factors is involved, including: the frequency and volume of aspirated material; efficacy of airway and lung clearance mechanisms; bacterial virulence; the person’s immune system; degree of dysbiosis in the lung microbiome; and co-morbid conditions.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.