History and exam
Key diagnostic factors
common
acute or chronic cough
Seen in 36% of patients with aspiration of gastric contents.[77] However, this presumes that the patient’s cough reflex is intact. Those with absent or diminished cough reflex (e.g., due to opioid intoxication or respiratory muscle weakness related to amyotrophic lateral sclerosis or critical illness myopathy) may have more consequential aspiration.[18][42]
fever
Extremely common after aspiration of gastric contents, occurring in 94% of cases.[77]
dyspnea
Extremely common after aspiration of gastric contents, seen in 78% of cases.[77] In severe cases, respiratory failure may result from noncardiogenic pulmonary edema.
wheezing
Occurs in 32% of patients after aspiration of gastric contents.[77]
crackles
Presence on lung auscultation is common after aspiration of gastric contents, occurring in 72% of cases.[77]
Other diagnostic factors
uncommon
laryngospasm
May be induced by laryngopharyngeal reflux, and serves as a protective mechanism against aspiration, though may lead to other dire consequences. In one series about 8% of patients with confirmed aspiration also had laryngospasm.[78]
Risk factors
strong
decreased level of consciousness (Glasgow coma scale score <9)
increased severity of illness
general anesthesia
Decreased level of consciousness results in loss of protective reflexes. Anesthetic drugs may decrease lower and upper esophageal sphincter tones, and promote ileus and gastroparesis, increasing risk for gastrolaryngeal reflux. Supine positioning and unsecured airways may add to the increased risk for reflux and subsequent aspiration.[8]
age >70 years
Risk of aspiration is higher in older patients, especially during and after the seventh decade, probably because of higher prevalence of aging-associated degenerative neurologic and cerebrovascular disorders that can cause dysphagia and/or impaired cough reflex.[27][35][41] Over 50% of patients with acute food asphyxiation are 71-90 years of age.[43]
head trauma
Can result in altered mental status and impaired airway reflexes. Also increases risk for gastric content aspiration because the elevated intracranial pressure that may result from head trauma delays gastric emptying.[44]
cerebrovascular disease
Over one third of patients with acute stroke have aspiration documented on radiologic studies.[27] Abnormal swallowing increases risk for aspiration.[27] Patients with dysphagia have delayed triggering of the pharyngeal motor response and decreased laryngeal elevation, resulting in poor coordination and timing of oral, pharyngeal, and laryngeal events during swallowing.[45]
endotracheal or tracheostomy tube
Indwelling endotracheal or tracheostomy tube raises risk for aspiration. Cuffed tubes are not completely protective and mechanically interrupt glottic closure or the lower esophageal sphincter.[41][46][47][48] Endotracheal intubation that lasts >8 hours can result in laryngotracheal complications, which increase the risk for aspiration after extubation.[49]
Aspiration has been documented in up to 45% of critically ill trauma patients after extubation. The mechanisms are multiple and include changes in glottis anatomy caused by vocal cord ulceration and laryngeal edema, and disruption of the swallowing reflex caused by muscle atrophy, incoordination, and diminished sensory abilities of the larynx.[50] Traumatic intubations (blood in the endotracheal tube, esophageal intubation, and multiple intubation attempts) increase the risk for aspiration after extubation. Patients are often sedated and critical illness further impairs swallow and cough reflexes. Muscle weakness associated with critical illness can further diminish effective cough that might otherwise offset aspiration events.[42]
dysphagia
Abnormal swallowing increases risk for aspiration.[27] Patients with dysphagia have delayed triggering of the pharyngeal motor response and decreased laryngeal elevation, resulting in poor coordination and timing of oral, pharyngeal, and laryngeal events during swallowing.[45]
High-risk conditions resulting in oropharyngeal dysphagia include neurologic disorders (cerebrovascular disease, head trauma, closed head injury, cervical spine injury, anoxia, seizure disorder, vocal cord paralysis, Parkinson disease, amyotrophic lateral sclerosis, Alzheimer disease), certain surgeries (for head and neck cancer, anterior and posterior cervical spine surgery, brain surgery, coronary artery bypass grafting, esophagogastrectomy), structural abnormalities (oropharyngeal tumors, tracheoesophageal fistula), gastrointestinal disorders (laryngopharyngeal reflux), tracheostomy, and adverse effects from sedatives and antipsychotics.
airway difficulties
barium meal
Can be aspirated during a barium radiographic exam.[Figure caption and citation for the preceding image starts]: Bronchoscopy showing barium aspiration in a lung transplant patient in the right mainstem bronchus after a barium swallow studyFrom the collection of Dr Kamran Mahmood [Citation ends].
[Figure caption and citation for the preceding image starts]: Barium aspiration. A barium swallow was conducted in a 53-year-old woman. Imaging revealed hyperdense airway-centered material in the left lower lobe consistent with barium aspiration bronchiolitis. A tracheoesophageal fistula was confirmedFrom the collection of Dr Augustine Lee; used with permission of Mayo Foundation for Medical Education and Research, all rights reserved [Citation ends].
weak
male sex
Risk for aspiration in males is almost twice that in females, probably because of the higher rates of neurologic and cardiovascular disorders in males.
gastroesophageal reflux disease
Independent risk factor for aspiration in critically ill patients and during perioperative period in patients undergoing general anesthesia.[8][20] Conditions that increase the risk for gastroesophageal reflux include esophageal disease (collagen vascular disease, cancer, achalasia, dysmotility), hiatal hernia, peptic ulcer disease, gastritis, bowel obstruction, ileus, and elevated intracranial pressure.[41]
feeding tubes
Nasoenteric feeding tubes may stimulate the pharynx and increase risk for aspiration by decreasing lower esophageal sphincter tone.[51] Gastric placement of feeding tubes increases risk for aspiration, and postpyloric placement of tube may have a protective effect.[20] Large feeding tubes increase risk, especially in infants and young children. It is unclear whether gastrostomy feeding tubes have lower risk for aspiration than nasogastric feeding.[44]
supine position
Supine positioning during dental, medical, or radiologic procedures, transport, and general anesthesia aligns the trachea and oropharynx, and facilitates gravitational flow of gastric content in the oropharynx. Also associated with difficulty swallowing. Sedation and anesthesia enhance risk of aspiration by obtunding the protective reflexes.[37]
delayed gastric emptying
High gastric residual volume is common in critically ill patients who receive enteral nutrition. This increases risk for vomiting or regurgitation of feeds and makes patients prone to aspiration.[44] Associated factors include abdominal surgery, sepsis, metabolic abnormalities (hyperglycemia, diabetes mellitus, hypokalemia), renal failure, increased intracranial pressure, and some drugs (e.g., opioids).
Glucagon-like peptide-1 (GLP-1) receptor agonists and dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 receptor agonists are known to delay gastric emptying, and because of retained gastric contents, their use is a risk factor for aspiration during procedures requiring general anesthesia or deep sedation.[32][33][34]
obesity
drugs that reduce esophageal sphincter tone
Drugs used in anesthesia and in the intensive care unit may reduce the lower and upper esophageal sphincter tone and increase risk for aspiration. Drugs include atropine, glycopyrrolate, dopamine, nitroprusside, ganglion blockers, thiopental, beta-adrenergic stimulants, halothane, and propofol. Tricyclic antidepressants also have this effect.[8]
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