2.11.08 aspiration pna gabbard

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Aspiration Pneumonia

Scott Gabbard, MD

2/11/2008


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Aspiration Pneumonia

Definition

Misdirection of gastric contents into the

larynx resulting from alteration in lowerairway defenses such as glottic closureand the cough reflex


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Incidence

Half of all adults aspirate small amounts oforopharyngeal contents in their sleep

Aspiration pneumonia may occur in up to10% of nursing home residents annually


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Predisposing Factors

Decreased consciousness

Alcohol

Drugs

Hepatic failure

CVA

Anesthesia


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Esophageal disorders

GERD

Stricture

Tracheoesophageal fistula

Incompetent cardiac sphincter

Protracted vomiting


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Disruption of glottic closure

Endotracheal intubation

NG tube

Endoscopy/bronchoscopy


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Neuromuscular disorders

Multiple sclerosis

Parkinsons

Myasthenia gravis


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Chemical Pneumonitis

Mendelson first described aspirationpneumonitis in 1946

61 OB patients aspirated gastric contentsafter ether anesthesia

All patients had recovery within 2 days


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Pathophysiology

Animal models demonstrate that clinically

significant pneumonitis results fromaspirating at least 1ml/kg of pH2.5


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Clinical features

Abrupt onset of dyspnea

Low grade fever

Pink frothy sputum

Diffuse crackles on exam

CXR: diffuse infiltrates


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Xray of chemicalpneumonitis 2 hours afteraspiration event


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Treatment

Ventilatory support may be necessary

Corticosteriods: beneficial in animalmodels, unsuccessful in humans

Antibiotics

Up to 25% of patients have bacterialsuperinfection (Dines et al)


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Bacterial Pneumonitis

Clinical features

Much more insidious onset than chemical

pneumonitis (days to weeks) Cough

Fever

Purulent sputum CXR: Infiltrate frequently in dependent

segments


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Xray of bacterialaspiration pneumonia


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Microbiology

Anaerobes

Peptostreptococcus Fusobacterium

Bacteroides

Gram negative bacilli

Klebsiella in alcoholics

E coli, serratia, proteus

Gram positive bacteria

Staph, Hemophilus, streptococcus


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Treatment Usual treatment 1-2 weeks (6-12 weeks for

abscess) Clindamycin

Superior response rates to PCN

Augmentin

Flagyl (dont use as single agent)

Moxifloxacin over other quinolones Cefotaxime/ceftriaxone over other cephalosporins


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Solid Particle Aspiration

Large particles

Sudden respiratory distress, cyanosis,

aphonia Heimlich!

Small particles

Irritative cough, unilateral wheezing Remember: bacterial superinfection is

common


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Assessment of Dysphagia

Clinical signs of dysphagia

Drooling

Coughing before, during, or after swallow

Multiple swallows per mouthful

Unusual head posturing while swallowing

Clinical exam for diagnosis Sensitivity 80%, Specificity 70%


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Assessment of Dysphagia

Modified barium swallow (MBS)

Patients swallow small amounts of different texturedbarium and evaluated by flouroscopy

One study demonstrated that MBS did not change thesensitivity of clinical exam, but did make the evaluationmore specific

Laryngoscopy


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Modified Barium Swallow

Stasis of contrast at the level of the pyriform sinuses (bluearrows) with subsequent aspiration (yellow arrows)


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Tube Feeding

Short term dysphagia

In moderately disabled CVA patients with

dysphagia, tube feeding has been shownto be associated with less pneumoniathan oral feeds (54% vs. 13%, p


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Tube Feeding

Long term dysphagia

No data exists to suggest that tube

feeding decreases pneumonia or prolongssurvival in patients with advanceddementia

102 patients with severe dementia: 58%

aspiration pneumonia in FT patients vs. 17%in those not receiving FT (Peck)


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Prevention

HOB elevated 30-45 degrees

Oral decontamination with chlorhexidine

Chin down - helps to narrow the airway Head tilt to stronger side when swallowing


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Prevention

Substance P

Believed to play a major role in the cough

and swallow pathwaysACE inhibitors prevent breakdown of

substance P

576 elderly patients with HTN: 3%pneumonia in those treated with ACEI vs.9% in those treated with Ca channelblocker (Arai)


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References

Haruka Tohara, Eiichi Saitoh, Keith A. Mays, Keith Kuhlemeier andJeffrey B. Palmer; Three Tests for Predicting Aspiration withoutVideofluorography; Dysphagia. 2003 Spring;18(2):126-34

Li, I. Feeding tubes in patients with severe dementia. AmericanFamily Physician. 2002 Apr 15;65(8):1605-10, 1515

Marek, PE. Aspiration pneumonia and dysphagia in the elderly.Chest. 2003 Jul;124(1):328-36

Paintal, HS. Kuschner, WG. Aspiration syndromes: 10 clinical pearls

every physician should know. Int J Clinical Practice.2007May;61(5):846-52.

Uptodate

www.radiologyassistant.nl/en/440bca82f1b77

2.11.08 aspiration pna gabbard

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