Primary prevention

The majority of hospital-acquired pneumonia and a significant proportion of community-acquired pneumonia in older people occur from microaspiration of infected oropharyngeal contents. Measures to identify oropharyngeal dysphagia and reduce oropharyngeal load of pathogenic organisms, particularly in patients with neurological disease, nursing-home patients with comorbidities, and intubated patients, can potentially help to reduce aspiration pneumonia.[33]

If patients are not considered at high risk of aspiration after a bedside swallow assessment, they should be fed orally and observed carefully, wherever possible.[3]

Refer patients with swallowing difficulty to a speech and language therapist (SLT). If an SLT considers a patient’s swallow as high risk for aspiration, and a ‘nil by mouth’ instruction is issued, formulate a plan that seeks to restore effective swallow. Arrange further assessment of swallow at an appropriate date. Consider a ‘nil by mouth’ instruction temporary, and take steps to minimise its duration where possible.[3] In patients approaching end of life, or those with moderate to severe dementia, a 'best interests' discussion should take place prior to a ‘nil by mouth’ instruction. 

If a patient has a newly diagnosed swallowing abnormality with a high risk of aspiration, and they are not felt to be approaching end of life, early nasogastric feeding (within 3 days of presentation with swallowing difficulties) has been shown to improve nutritional status and outcomes. Continue attempts to improve swallow, with a view to restore normal eating.[3]  

Consider percutaneous endoscopic gastrostomy (PEG) when an abnormal swallow presents a continuing high risk of aspiration and when nasogastric tubes are either poorly tolerated or fail to provide adequate nutrition. PEG tubes should not always be considered permanent and can be removed if safe swallow returns.[3] 

If consuming food and liquid as normal is felt to present a high risk of aspiration pneumonia, trial cold carbonated drinks or thickened fluids or feeds.[3]

Good oral hygiene is recommended, and appears to reduce the rate of aspiration pneumonia.[3] Oral care, including a combination of professional cleaning of the oral cavity once a week, tooth brushing after each meal, cleaning dentures once a day, and gargling of disinfectant solution, can reduce the number of pathogenic bacteria in the oropharyngeal secretions and has the potential to reduce the occurrence and mortality from aspiration pneumonia, although the supporting studies may have limited methodological validity.[34][35][36][37]​ Oral care is most beneficial when it is provided by dental professionals; oral care provided by nurses had no appreciable reduction in mortality from pneumonia.[38]

Perform an oral examination in all hospitalised patients at risk of or with suspected aspiration pneumonia, and in care home residents (at least weekly). Check for signs of infection, quality of dentition, food residue, and cleanliness of mucosal surfaces. Treat any abnormalities and extract any non-restorable teeth.[3] 

In Chinese and Japanese patients at risk of aspiration after stroke, if not contraindicated, prescribe ACE inhibitors to reduce the risk of aspiration pneumonia. Insufficient evidence exists to support this in other ethnic groups.[3]​

The patient should remain in an upright or elevated position at least 1 to 2 hours after meals. Feeding tubes require regular adjustment to prevent misplacement. Tube feeding residual volume in the stomach should be monitored, and tube feedings should be withheld if the residual volume exceeds 50 mL. Continuous pump nasogastric feeding does not reduce the incidence of pneumonia compared with bolus feeding. In critically ill patients, there is moderate-quality evidence that post-pyloric feeding compared with gastric feeding is associated with a 30% lower rate of pneumonias.[39] Aspiration pneumonias are reduced in gastrostomy patients with elemental diets and mosapride.[40][41]

Prophylactic antibiotic therapy after a recognised episode of aspiration may not prevent the subsequent development of bacterial pneumonia; rather, it may select for resistant organisms. No evidence-based recommendations can currently be made for any pharmacological intervention for prevention of aspiration pneumonia.[42]

There is little evidence that preoperative fasting reduces the risk of perioperative aspiration.[43] The routine preoperative use of antacids or medications that block gastric acid secretions is not recommended in patients who have no apparent increased risk for pulmonary aspiration (conditions that increase risk include gastro-oesophageal reflux disease, hiatal hernia, ileus or bowel obstruction, pregnancy, and obesity).[20] One systematic review showed benefit from use of histamine-2 receptor antagonists in reducing gastric volume and increasing pH, thus reducing the number of patients at risk of acid aspiration.[44] Despite this, there is insufficient evidence to justify suppressing gastric acid, as administration of a proton-pump inhibitor or histamine-2 receptor antagonist may be associated with an increased risk of pneumonia.[45]

Similar trends for reducing risk of aspiration pneumonitis were noted in women undergoing caesarean section under general anaesthesia with usage of H2 receptor antagonists, although quality of evidence was poor.[46]

One study of metoclopramide use within 7 days of stroke in patients with a nasogastric tube showed reduced rates of pneumonia as compared with placebo.[47]

Secondary prevention

The majority of patients with aspiration pneumonia will have an impaired swallow. The primary preventive measures discussed above should also be taken into consideration to avoid further aspiration.

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