Primary prevention

Prevention can be focused on issues related to infection control, avoidance of certain procedures/exposures, and specific management strategies.[25]​​

Infection control

  • Hand hygiene is the single most important primary prevention strategy a healthcare worker can perform, as it prevents the transmission of multidrug-resistant (MDR) pathogens that cause HAP, such as Acinetobacter.[29][30][31]

  • Other infection control measures such as staff education and isolation to reduce cross-infection with MDR pathogens should be used routinely.[3]

  • Surveillance of intensive care unit (ICU) infections accomplishes several tasks: identifies and quantifies endemic and new MDR pathogens, prepares timely data for infection control, and guides appropriate antimicrobial therapy in patients with suspected HAP.[3]

  • Without the practice of infection prevention and control, a patient may be admitted without an infection and be discharged with a serious morbidity, or even die before discharge. The process starts with colonization with an MDR organism, proceeds to invasion of sterile tissue (e.g., lung, blood) with the colonized pathogen, and ends with disease (e.g., HAP, bacteremia) or even death.

Exposures to avoid

  • Antimicrobials should only be used when absolutely necessary, to prevent resistant antimicrobials from residing in ICUs and colonizing patients.

  • Unnecessary intubation may be averted with noninvasive positive pressure ventilation, which is an intermediary method of oxygenation and ventilation for patients in respiratory distress who are not experiencing respiratory failure, and are not expected to require assistance for long periods of time.[25]​ A meta-analysis reviewed 16 randomized/quasi-randomized trials and found improved outcomes: decreased ventilator-associated pneumonia (VAP) rate, lower mortality, shorter ICU stay, and shorter length of hospital stay.[32]​​​ [ Cochrane Clinical Answers logo ] ​ Using noninvasive ventilation immediately after planned extubation has also been shown to decrease the rate of reintubation.[33] If appropriate, safe and feasible, high-flow nasal oxygen by nasal cannula may also be an option to avoid intubation, minimize duration of intubation and prevent reintubation.[25]​ Although some meta-analyses suggest that high-flow nasal cannula may reduce ICU and hospital length of stay compared with noninvasive positive pressure ventilation, others do not.[34][35]

  • Sedation of ventilated patients should be minimized where possible.​[25]​ Potential strategies to minimize sedation include nurse-driven protocols for targeted light sedation and daily sedative interruptions (i.e., spontaneous awakening trials) for patients without contraindications.[25]​ Preventing unnecessary sedation prevents intubating patients just to "protect their airway". Interrupting sedation has been shown to shorten the duration of intubation and thus decrease VAP.[27] Using a sedation vacation requires more ICU staffing, so the availability of resources should be anticipated before adding the practice to protocols. CDC: National Healthcare Safety Network Opens in new window CDC: Healthcare Infection Control Practices Advisory Committee Opens in new window

Specific management strategies

  • Although replacing ventilator circuits weekly has become the standard of care in some centers, there are data indicating routine circuit change is not needed.[36][37]​​ SHEA/IDSA/APIC (The Society for Healthcare Epidemiology of America/Infectious Diseases Society of America/Association for Professionals in Infection Control and Epidemiology) recommend to change ventilator circuits only when visibly soiled or malfunctioning or per manufacturers' instructions.[25]​ Cuff pressure and volume should be maintained at the minimal occlusive settings to prevent clinically significant air leaks around the endotracheal tube, typically 20-25 cm H₂O.[25]

  • Oral care is the most commonly studied strategy to prevent HAP, although there is a paucity of robust data.[25]​ SHEA/IDSA/APIC (The Society for Healthcare Epidemiology of America/Infectious Diseases Society of America/Association for Professionals in Infection Control and Epidemiology) recommend daily oral care without chlorhexidine to prevent HAP.[25][26]​​ Evidence shows that chlorhexidine mouthwash or gel, as part of oral hygiene care (OHC), probably reduces the incidence of developing VAP in critically ill patients from 26% to about 18%, when compared with placebo or usual care. Chlorhexidine made no difference to mortality, duration of mechanical ventilation or duration of stay in the intensive care unit, although the evidence was low certainty. OHC including both antiseptics and toothbrushing may be more effective than OHC with antiseptics alone to reduce the incidence of VAP and the length of ICU stay, but, again, the evidence is low certainty.[26]​

  • Bathing critically ill patients with chlorhexidine is a practice in some ICUs. However it is not clear whether chlorhexidine baths reduce hospital-acquired infections, mortality, or length of stay in the ICU because the available evidence is of very low certainty.[38]

  • Elevating the head of the bed, unless medically contraindicated, is recommended by the American Thoracic Society, SHEA/IDSA/APIC (The Society for Healthcare Epidemiology of America/Infectious Diseases Society of America/Association for Professionals in Infection Control and Epidemiology), and the Centers for Diseases Control and Prevention, and is supported by most experts despite poor-quality evidence to support the practice.​[24][25]​​​​​ A semirecumbent position of 45° was found to have significantly lower incidence of clinically diagnosed VAP than 15° to 30°.[39]

  • Endotracheal tubes may prevent VAP by incorporating design features that reduce bacterial colonization and biofilm formation, or by suctioning of subglottic secretions that may otherwise be aspirated.[40][41]​​​​ Studies have shown a significant reduction in the incidence of early-onset VAP, and other outcomes, using specialized endotracheal tubes.​[40][41][42][43]​​​​ Passive humidifiers or heat-moisture exchangers that decrease ventilator circuit colonization have not been shown to consistently reduce the incidence of VAP.[44]

  • SHEA/IDSA/APIC (The Society for Healthcare Epidemiology of America/Infectious Diseases Society of America/Association for Professionals in Infection Control and Epidemiology) recommend to consider using selective decontamination of the oropharynx and digestive tract to decrease microbial burden in ICUs with low prevalence of antibiotic-resistant organisms.[25]​ Antimicrobial decontamination is not recommended in countries, regions, or ICUs with high prevalence of antibiotic-resistant organisms.[25]

  • Multiple meta-analyses have reported a possible association between probiotics and lower rates of VAP.[45][46][47]​​​ However, these analyses included unblinded studies that were at high risk of bias. Restricting meta-analyses to double-blinded studies only shows no association between probiotics and VAP.[48]​​ This lack of association has also been demonstrated in a large, rigorous, multicenter, randomized trial conducted after the most recent meta-analysis.[49]

  • Transpyloric feeding (in the upper small bowel) has been shown to be associated with significantly less VAP compared with gastric feeding in mechanically ventilated patients.[50]

Many of these preventative actions have been put together in "bundles" for healthcare workers to practice in a comprehensive format. Such bundles have been criticized for providing a lack of personal care and for possibly leading to the carrying out of tasks that may actually be harmful to certain patients. A prospective study in the Netherlands compared mortality between 52 ICUs participating in a sepsis bundle program versus 30 ICUs not participating.[51] The study found decreased in-hospital mortality (adjusted odds ratio per month = 0.992 [0.986 to 0.997]) equivalent to 5.8% adjusted absolute mortality reduction over 3.5 years in the ICU that used the sepsis bundle program.

There is insufficient evidence to determine the effect of vitamin C or vitamin D supplementation in the prevention (or treatment) of pneumonia.[52][53]

Secondary prevention

Influenza vaccine is indicated for all patients in a facility where an outbreak is occurring, or who meet Centers for Disease Control and Prevention criteria. Bacterial pneumonia can follow influenza, so immunization is important. All healthcare workers should receive an influenza vaccine unless contraindicated.​[144]​​

Pneumococcal vaccination is not specifically indicated for patients admitted to hospital, but may help prevent infection due to Streptococcus pneumoniae in patients who have comorbidities. For details on current vaccination schedules and special patient populations, check the latest Advisory Committee on Immunization Practices vaccination schedule. CDC: ACIP recommendations Opens in new window​ 

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