• Summary
  Click here to print a Quick Reference Guide
• Background
• Clinical Diagnosis
• Severity Assessment
• Investigation
• Treatment
• Non-Antimicrobial Treatment
• Empirical Antimicrobial Treatment
• Directed Antimicrobial Treatment (when microbiology results are known)
• Duration of Treatment
• Switch to oral agent(s)
• Treatment Failure
• Referral Criteria

Prevention
The following groups are at increased risk of aspiration pneumonia therefore complete a swallowing test in these patients

• Stroke - up to 45% unsafe to swallow on first day after event. Pneumonia is the commonest non-neurological complication in the first week occurring in up to 21% by discharge.
• Multiple sclerosis
• Parkinson’s disease
• Motor Neurone Disease
• Any neurological disorder resulting in dysphagia
• Altered conscious level and inability to protect airway
• Any upper gastro-intestinal pathology with increased risk of gastric reflux
• Nasogastric and PEG tubes, even if nil by mouth

Reduce aspiration risk in tube fed patients:

• Keep > 30⁰ head up
• Involve dietitians whenever tube feeding is contemplated
• Build up feed regimes slowly as per protocol
• Use the out of hours feeding policy when necessary to initiate feeding urgently
• Avoid excessive infusion rates (start at low rate of 30mL/hour and up to 150 mL/hour is usually well tolerated)
• Attend to oro-pharyngeal hygiene rigorously as these patients have higher colonisation rates with pathogenic organisms and this is thought to contribute to the chest sepsis after aspiration episodes
• Prokinetic agents (such as domperidone 10mg 8-hourly) may be used but have limited evidence of benefit
• Post-pyloric tubes have limited evidence of benefit

Key diagnostic criteria: See HAP guideline

Investigations required: See HAP guideline

Empirical (initial) antimicrobial treatment: See table 1.
If previous microbiology results are available i.e. is the patient colonised with particular strains of bacteria, consider discussion with microbiology.

^x severity of infection is based on clinician assessment.

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Aspiration pneumonitis and pneumonia are thought to be common causes of hospital-acquired pneumonia (HAP) but exact figures depend on the patient population studied and definitions used.
Aspiration pneumonia refers to the pulmonary consequences resulting from the abnormal entry of fluid, particulate exogenous substances, or endogenous secretions into the lower airways. There are usually two requirements to produce aspiration pneumonia:

• Compromise in the usual defenses that protect the lower airways including glottic closure, cough reflex, and other clearing mechanisms
• An inoculum deleterious to the lower airways by a direct toxic effect, stimulation of an inflammatory process from a large enough bacterial inoculum, or obstruction due to a sufficient volume of material or particulate matter

Most cases of pneumonia arise following the aspiration of microorganisms from the oral cavity or nasopharynx. The term aspiration pneumonia should be reserved for pneumonitis resulting from the altered clearance defenses noted above. The pathogens that commonly produce pneumonia, such as Streptococcus pneumoniae, Haemophilus influenzae, gram-negative bacilli, and Staphylococcus aureus, are relatively virulent bacteria so that only a small inoculum is required and the aspiration is usually subtle. A true aspiration pneumonia, by convention, usually refers to an infection caused by less virulent bacteria, primarily anaerobes, which are common constituents of the normal flora in a susceptible host prone to aspiration [Evidence Level C].

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Respiratory symptoms, especially dyspnoea and wheeze, are common after aspiration episodes.

Patients should be assessed by a doctor as soon as possible after such an episode and vital sign observations monitored at least 4 hourly.
If they do not have clinical features which satisfy the criteria for hospital acquired pneumonia, they should be observed closely but NOT receive antibiotics routinely. Many cases settle and are due to chemical pneumonitis, though this may be impossible to distinguish from bacterial pneumonia.

When doubt exists in particular clinical circumstances, senior medical advice should be sought [Evidence Level C and D].¹

Review progress daily. In patients initially assessed as having a mild infection clinically deteriorate, manage according to the moderate-severe guidelines

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There are no recognised criteria for establishing the severity of aspiration pneumonia. A clinician must make an individual assessment to classify a patient as mild or moderate-severe severity [Evidence Level D].

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See Hospital Acquired Pneumonia guideline

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Prevention
At risk patients
Certain patients are at higher risk of aspiration episodes and these are those with:

• Stroke - up to 45% unsafe to swallow on first day after event. Pneumonia is the commonest non-neurological complication in the first week occurring in up to 21% by discharge.
• Multiple sclerosis
• Parkinson’s disease
• Motor Neurone Disease
• Any neurological disorder resulting in dysphagia
• Altered conscious level and inability to protect airway
• Any upper gastro-intestinal pathology with increased risk of gastric reflux
• Nasogastric and PEG tubes, even if nil by mouth

Screening
All stroke patients MUST be screened on admission for dysphagia using a standardised swallow assessment, described on the stroke clerking proforma.
Other patients in high risk groups should be tested if any clinical suspicion of dysphagia from the history, any weight loss or recurrent chest infections.
Patients noted to be coughing persistently, particularly on liquids, should be screened with a standardised test swallow for neurological dysphagia as below [Evidence Level C].
Patients with moderate to severe dementia, of whatever cause, present particular challenges in management. It is important to involve senior clinicians as soon as possible because ethical and communication dilemmas occur. Often, when dementia progresses to the point where swallowing function is affected, artificial tube feeding does not alter the outcome in terms of survival and quality of life. A policy of careful hand feeding with the optimal consistency of feed and fluids is often more acceptable [Evidence Level D].

Standardised Swallow Test [Evidence Level B]
Ensure patient is sat upright and alert. The test may be performed by any dysphagia trained member of staff.

Reducing aspiration risks
To reduce aspiration risk in tube fed patients:

• Keep > 30⁰ head up
• Involve dietitians whenever tube feeding is contemplated
• Build up feed regimes slowly as per protocol
• Use the out of hours feeding policy when necessary to initiate feeding urgently
• Avoid excessive infusion rates (start at low rate of 30mL/hour and up to 150 mL/hour is usually well tolerated)
• Attend to oro-pharyngeal hygiene rigorously as these patients have higher colonisation rates with pathogenic organisms and this is thought to contribute to the chest sepsis after aspiration episodes
• Prokinetic agents (such as domperidone 10mg tds) may be used but have limited evidence of benefit
• Post-pyloric tubes have limited evidence of benefit

Non antimicrobial therapy

Ensure swallow test has been completed and review all measures to reduce aspirations have been completed.

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Aspiration pneumonia: aetiology
Streptococci and anaerobes have been identified as the cause of community acquired aspiration pneumonia where sample collection has been of good quality (transtracheal aspirates). In studies where sample collection was less good e.g. tracheal aspirates and in hospital acquired aspiration pneumonia, coliforms and S. aureus have been isolated in patients with aspiration pneumonia. It is unclear if these bacteria represent infecting or colonising isolates. Where the severity of infection is mild treatment is directed against streptococci and anaerobes. Treatment of mild-moderate aspiration pneumonia with clindamycin has been shown to be as effective as treatment with a co-amoxiclav equivalent and a carbapenem⁵. Clindamycin covers only Gram positive bacteria (staphylococci and streptococci) and anaerobes supporting our mild aspiration pneumonia regime which covers streptococci and anaerobes.

Where severity is moderate to severe, using the precautionary principal, S.aureus and coliform cover is also provided [Evidence Level C and D].^2/3/4

In the event of an acute witnessed aspiration episode, commencing prophylactic antibiotic is not normally indicated. In this situation, instigate usual conservative management and observe. If the patient is improving after 36 hours antimicrobial therapy is not normally required.

Treatment

For empirical therapy see table 1. If previous microbiology results are available i.e. is the patient colonised with particular strains of bacteria, consider discussion with microbiology. Review progress daily. In patients initially assessed as having a mild infection clinically deteriorate, manage according to the moderate-severe guidelines

^x severity of infection is based on clinician assessment.

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Directed Therapy (for specific HAP pathogens) [Evidence Level C]:

Sputum results may represent colonisation of the upper respiratory tract and not infection. Therefore assess the patient’s response to empirical therapy before changing to directed antimicrobial therapy.

Anaerobic cover should be maintained in all directed therapy regimes. Metronidazole and Piperacillin/tazobactam have anaerobic cover.

Methicillin-susceptible Staphylococcus aureus

Discuss with microbiology to review susceptibilities.
IV Flucloxacillin 1g 6 hourly may need adding to treatments for mild infection.

Methicillin-resistant Staphylococcus aureus
If previous positive culture(s) for MRSA consider adding cover for MRSA with either:

1st line PO/IV Linezolid *600mg 12 hourly or 2nd line IV Teicoplanin (see dosing guideline) *Linezolid has a number of drug interactions/contraindications. Please see full guidance to check suitability for the patient.

Gram-negative bacilli (e.g. Coliforms, Acinetobacter baumannii, Stenotrophomonas maltophilia).
Therapy should be targeted on a case-by-case basis, dependent on the susceptibilities of the causative organism. Please discuss these cases with the duty microbiologist for further advice and approval
Pseudomonas aeruginosa
IV Piperacillin/tazobactam 4.5g 6 hourly

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Suggest complete IV therapy if initiated on empirical therapy.
Metronidazole PO can be considered as equivalent to IV Metronidazole .

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Referral and referral tests
When possible neurological dysphagia is detected, referral to speech and language therapy (SALT) is recommended. Further techniques such as videofluoroscopy (VF) and/or functional endoscopic evaluation of swallowing (FEES) may be very useful. VF is a procedure using radiolabelled boluses of food and taking video images of swallowing so it can be analysed in detail by SALT and radiologist together. In particular, clinically silent aspiration can be detected i.e. with no cough or wheeze etc triggered. Different consistencies may be used to find the safest and most well tolerated. FEES is an endoscopic technique which allows direct visualisation of the swallowing mechanism and any aspiration again with different consistencies. Both techniques are well validated and, in general, local expertise and availability determine which is more frequently utilised.

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