Hospital-acquired pneumonia is a significant cause of morbidity and mortality. This section will discuss risk factors for hospital-acquired pneumonia and methods/techniques for preventing hospital-acquired pneumonia (which is sometimes referred to as healthcare-associated pneumonia) in patients who are mechanically ventilated and those who are not.
The most important risk factor for hospital-acquired pneumonia is mechanical ventilation. Other risk factors include180:
- Age > 55 years
- Chest or upper abdominal surgery
- Chronic lung disease
- Chronic renal failure
- Depressed consciousness
- Frequent ventilator circuit changes
- Increased gastric pH, e.g. from therapeutic use of H2 blockers or proton pump inhibitors
- Intracranial pressure monitoring
- Medications, e.g., glucocorticoids, muscle relaxers, opioids
- Multiple central venous catheter placements
- Multiple surgeries
- Multiple trauma
- Prolonged intubation, re-intubation
Preventing Hospital-Acquired Pneumonia
For mechanically ventilated patients, measures that can prevent hospital- acquired pneumonia include avoiding intubation when possible, elevating the head of the bed, oral hygiene with an antiseptic, maintaining physical conditioning, minimizing the use of sedation, minimizing pooling of secretions above the endotracheal tube, proper maintenance of ventilator circuit, and staff education.180
There has been comparatively little research on the prevention of hospital acquired pneumonia in the non-ventilated patient, but proper positioning, early identification and treatment of dysphagia, good oral hygiene, using an antiseptic mouth rinse, and conscientious use of Standard Precautions and infection control techniques may be helpful.181
The following are the CDC and the American Thoracic Society recommendations for the prevention of hospital-acquired pneumonia.182, 183 Recommendations from the Institute for Healthcare Improvement are included, as well.184
Staff education: Staff knowledge of the risks of hospital-acquired pneumonia and their knowledge of, and compliance with prevention techniques are critical for reducing the incidence and severity of this disease.
Conduct surveillance in ICU patients: Do not routinely perform surveillance cultures of patient, equipment or devices
Sterilization and Disinfection:
- Thoroughly clean all equipment. When possible use steam sterilization or high-level disinfection by wet heat pasteurization
- Use sterile water for rinsing reusable semi-critical respiratory equipment after chemical disinfection. If this not feasible, rinse with filtered water.
- Adhere to provisions in the FDA’s enforcement document for single-use devices that are reprocessed by third parties.
- Do not routinely sterilize or disinfect the internal machinery of mechanical ventilators.
- Do not routinely change the breathing circuit humidifiers based on duration of use. Clean only when visibly soiled or malfunctioning.
- Breathing-circuit tubing condensate: Periodically drain and discard any condensate. Make sure the condensate does not drain toward the patient. Wear gloves during procedure or handling of condensate. Wash hands with soap and water or with alcohol-based hand rub after the procedure.
- No recommendation can be made for placing a filter or trap at the distal end of the expiratory-phase tubing to collect condensate.
- Use sterile water to fill bubbling humidifiers
- No recommendation can be made for the preferential use of a close, continuous-feed humidification system.
- Ventilator breathing circuits with heat moisture exchange (HME): No recommendation can be made for the preferential use of either HMEs or heated humidifiers to prevent pneumonia in patients receiving mechanically assisted ventilation. Change an HME that is in use on a patient when it malfunctions mechanically or becomes visibly soiled. Do not routinely change an HME that is in use on a patient more frequently than every 48 hours. Do not routinely change the breathing circuit attached to an HME while it is in use on a patient
- Oxygen humidifiers: Follow manufacturers' instructions for the use of oxygen humidifiers. Change the humidifier-tubing (including any nasal prongs or mask) when it malfunctions or becomes visibly contaminated.
- Small-volume medication nebulizers and in-line and hand-held nebulizers: Between treatments on the same patient, clean, disinfect; rinse with sterile water (if rinsing is needed), and dry small-volume in-line or hand-held medication nebulizers. Use only sterile fluid for nebulization, and dispense the fluid into the nebulizer aseptically. Whenever possible, use aerosolized medications in single-dose vials. If multi-dose medication vials are used, follow manufacturers’ instructions for handling, storing, and dispensing the medications.
- Mist-tents: Between uses on different patients, replace mist tents and their nebulizers, reservoirs, and tubing with those that have been sterilized or had high-level disinfection. No recommendation can be made about the frequency of routinely changing mist-tent nebulizers, reservoirs, and tubing while in use on one patient. Mist-tent nebulizers, reservoirs and tubing that are used on the same patient to should receive daily low-level disinfection (e.g., with 2% acetic acid) or pasteurization followed by air-drying.
- Other devices: Between uses on different patients, sterilize or subject to high-level disinfection portable respirometers and ventilator thermometers; reusable hand-powered resuscitation bags; no recommendation can be made about the frequency of changing hydrophobic filters placed on the connection port of resuscitation bags.
- Anesthesia machines and breathing systems or patient circuits: Do not routinely sterilize or disinfect the internal machinery of anesthesia equipment. Between uses on different patients, clean the reusable components of the breathing system or patient circuit and then sterilize or subject them to high-level liquid chemical disinfection or pasteurization in accordance with the device manufacturers’ instructions for their reprocessing. No recommendation can be made about the frequency of routinely cleaning and disinfecting unidirectional valves and carbon dioxide absorber chambers
- Follow published guidelines and manufacturers' instructions about in-use maintenance, cleaning, and disinfection or sterilization of other components or attachments of the breathing system or patient circuit of anesthesia equipment No recommendation can be made for placing a bacterial filter in the breathing system or patient circuit of anesthesia equipment
- Pulmonary-function testing equipment: Do not routinely sterilize or disinfect the internal machinery of pulmonary-function testing machines between uses on different patients. Change the mouthpiece of a peak flow meter or the mouthpiece and filter of a spirometer between uses on different patients.
- Room-air humidifiers and faucet aerators: Do not use large-volume room-air humidifiers that create aerosols unless they can be sterilized or subjected to high-level disinfection at least daily and filled only with sterile water.
- No recommendation can be made about the removal of faucet aerators from areas for immunocompetent patients
- If Legionella spp. are detected in the water of a transplant unit and until Legionella spp. are no longer detected by culture, remove faucet aerators in the unit
Tracheostomy Care and Suctioning
Good tracheostomy care reduces morbidity, and it also reduces the amount of time to decannulation.185, 186 Principles of good tracheostomy care include:
- All supplies to replace a tracheostomy tube should be at the bedside or within easy reach.
- Humidification should be used if the patient is mechanically ventilated or has thick secretions.
- Perform tracheostomy under aseptic conditions.
- When changing a tracheostomy tube, wear a gown, and use aseptic technique.
- No recommendation can be made for the daily application of topical antimicrobial agent(s) at the tracheostoma.
- Perform cuff pressure checks as needed.
- Cuffs should be deflated when the patient no longer needs mechanical ventilation.
Suctioning of respiratory tract secretions: Suctioning is an essential part of care for certain patients who are mechanically ventilated or have a tracheostomy, but it places them at risk for infection and hospital-acquired pneumonia. The following advice and recommendations can help prevent these complications.
- No recommendation can be made for the preferential use of either the multiuse closed-system suction catheter or the single-use open system suction catheter for prevention of pneumonia.187, 188
- Sterile gloves do not have to be worn.189
- No recommendation can be made about the frequency of routinely changing the in-line suction catheter of a closed-suction system in use on one patient.
- If the open-system suction is employed, use a sterile single-use catheter.
- Use only sterile fluid to remove secretions from the suction catheter if the catheter is to be used for re-entry into the patient's lower respiratory tract. Routine use of saline is not recommended.190
Modifying Host Risk for Infection and Hospital-Acquired Pneumonia: Vaccination
Vaccination is an important part of protecting patients against hospital-acquired pneumonia and pneumonia. Patients at risk who should be given pneumococcal vaccination include191-195:
- All infants and children age 2 to 59 months.
- Children 60 to 71 months with underlying medical conditions including immunocompetent children with chronic heart disease (particularly cyanotic congenital heart disease and heart failure), children who have cerebrospinal fluid leaks, chronic lung disease, asthma (if there is a need for high- dose corticosteroids), cochlear implants, or diabetes.
- Children with functional or anatomic asplenia, including sickle cell disease or other hemoglobinopathies, children who have congenital or acquired asplenia, or splenic dysfunction.
- Children with immunocompromising conditions including chronic renal failure, congenital immunodeficiency (includes B or T cell deficiency, complement deficiencies and phagocytic disorders; excludes chronic granulomatous disease), generalized malignancies, HIV infection, Hodgkin’s disease, nephrotic syndrome, leukemia, lymphoma, solid organ transplant, or other diseases requiring immunosuppressive drugs.
- Children ≥6 years, adolescents ≤18 years and adults ≥19 years.
- Person who have these underlying medical conditions: Anatomic asplenia, including sickle cell disease or other hemoglobinopathies, congenital or acquired asplenia; immunocompetent persons with cerebrospinal fluid leaks or cochlear implants; immunocompromising conditions including congenital or acquired immunodeficiency (this includes B or T cell deficiency, complement deficiencies and phagocytic disorders, excludes chronic granulomatous disease); HIV infection, chronic renal failure, nephrotic syndrome, leukemia, lymphoma, Hodgkin’s disease; generalized malignancies; solid organ transplant; multiple myeloma; or other diseases requiring immunosuppressive drugs (including long term systemic corticosteroids and radiation therapy).
- All adults ≥65 years.
No recommendation can be made for the routine administration of preparations of granulocyte colony stimulating factor (GCSF) medications or intravenous gamma globulin for prophylaxis against healthcare-associated pneumonia
No recommendation can be made for the routine administration of glutamine for prevention of healthcare-associated pneumonia.196
Aspiration is a significant risk factor for hospital-acquired pneumonia and pneumonia. Measures that can prevent and decrease the risk for aspiration include180,181,197-199:
- As soon as the clinical indications for their use are resolved, remove devices such as endotracheal, tracheostomy, or enteral tubes from patients.
- Limit the use of sedating or paralytic agents as these drugs can depress cough and other host-protective mechanisms.
- Maintain endotracheal tube cuff pressure at 20-30 cm H2O.
- Condensation in the ventilator circuit can become contaminated. Care should be taken to prevent condensation from reaching the lower airway or the nebulizer chamber.
- Use non-invasive ventilation (NIV) if possible; this will reduce the need for and duration of endotracheal intubation.
- If possible and if not medically contraindicated, use noninvasive positive-pressure ventilation delivered continuously by face or nose mask in preference to endotracheal intubation in patients who are in respiratory failure and who do not need immediate intubation.
- If possible and if not medically contraindicated, use NIV during the weaning process. This can shorten the duration of endotracheal intubation.
- As much as possible, avoid repeat endotracheal intubation in patients who have received mechanically assisted ventilation.
- Unless contraindicated by the patient’s condition, perform orotracheal rather than nasotracheal intubation.
- If feasible, use an endotracheal tube with a dorsal lumen above the endotracheal cuff to allow drainage (by continuous or frequent intermittent suctioning) of tracheal secretions that accumulate in the subglottic area.
- Before deflating the cuff of an endotracheal tube in preparation for extubation, tube removal or before moving the tube, clear secretions from above the cuff. Ensure that secretions are cleared from above the tube cuff.
Prevention of aspiration associated with enteral feeding199-202:
- Maintain the head of the bed at 30-45° unless contraindicated.
- Routinely verify appropriate placement of the feeding tube, e.g., every four hours. Auscultating for air, checking the pH of the aspirate, and inserting the open end of a tube into water are not reliable methods of confirming tube placement; capnography is preferred. Radiographic confirmation is the gold standard.
- Routinely assess the patient’s tolerance for enteral feedings, e.g., every four hours.
- Gastric residual volume (GRV) does not correlate with the in the incidences of aspiration or pneumonia. Withholding feeding if the GRV is < 500 mL is contraindicated unless the patient has signs of feeding intolerance.
- Prokinetic medications such as metoclopramide should be used if possible.
- If the patient is at high-risk for aspiration or if he/she is intolerant to bolus delivery of enteral nutrition, deliver enteral nutrition by continuous infusion.
- Use sedatives sparingly.
- Consider a swallowing evaluation before oral feedings are started for recently extubated patients who had been intubated for more than 2 days.
- No recommendation can be made for using small-bore tubes for enteral feeding.
- Feedings can be delivered in the stomach, the jejunum, or the duodenum. The selection of the delivery site should be made on a case-by-case basis; if the patient has a high-risk for aspiration, a site lower than the stomach is preferred.
Prevention or modulation of oropharyngeal colonization
Bacteria are present in the oral cavity, both normal flora and bacteria that are transmitted to the patient during hospitalization. Aerobic and facultatively anaerobic gram-negative bacilli frequently colonize the oral cavities in patients who are hospitalized and/or immunocompromised. These pathogens are a significant cause of hospital-acquired pneumonia.203
Patients who are mechanically ventilated have an increase in oral biofilm, xerostomia, colonization of the oral cavity by pathogens, and no ability to self-clean, all of which increase the risk for ventilator-associated pneumonia.204
Oropharyngeal cleaning and decontamination with an antiseptic agent can help reduce the number of these pathogens and reduce the incidence of hospital-acquired pneumonia and ventilator-acquired pneumonia.203-207
Chlorhexidine is the most commonly used and studied oral antiseptic for the prevention of oral decolonization and prevention of hospital-acquired pneumonia, but it is not clear which antiseptic agent is the most effective, and the optimal oral hygiene protocol has not been determined.204, 208
Develop and implement a comprehensive oral-hygiene program (that might include the use of an antiseptic agent) for patients in acute-care settings or residents in long-term care facilities who are at high-risk of developing healthcare-associated pneumonia
No recommendation can be made for the routine use of an oral chlorhexidine rinse for the prevention of healthcare associated pneumonia in all postoperative or critically ill patients or other patients at high risk for pneumonia.209
Use an oral chlorhexidine gluconate (0.12%) rinse during the perioperative period in adult patients who had cardiovascular surgery was shown to reduce the incidence of ventilator-associated pneumonia.210
Prevention of gastric colonization
Mechanical ventilation for > 48 hours is considered a risk factor for stress ulcer and gastrointestinal bleeding,211 and stress ulcer prophylaxis is recommended for these patients.210
Oral proton pump inhibitors, oral or IV, are the drug of choice.211 Antacids, histamine-2 receptor blockers, and sucralfate can also be used.210 Evidence comparing the proton pump inhibitor, antacids, histamine-2 receptor blockers, and sucralfate in terms of efficacy and safety appear to favor the proton pump inhibitors, but studies are few and limited in scope.
There is evidence that stress ulcer prophylaxis decreases the incidence of stress ulcers and bleeding but that it increases the risk for nosocomial pneumonia.211 However, experts feel that this risk is preferable to the development of stress ulcer and bleeding and that the studies that have associated stress ulcer prophylaxis with nosocomial pneumonia had methodologic flaws and were poorly controlled for co-morbidities.211
Enteral nutrition may have a protective effect against stress ulcer. But unless it is contraindicated, patients who are receiving enteral nutrition and need stress ulcer prophylaxis should be treated with a proton pump inhibitor or another protective drug.211
Prevention of postoperative pneumonia
Patients who are at-risk for developing post-operative pneumonia include212:
- Age > 50
- Chronic corticosteroid use
- Chronic obstructive pulmonary disease
- Comorbid disease (ASA class ≥2)
- Congestive heart failure
- Consumption of >2 alcoholic drinks per day within two weeks
- Functional dependence
- History of stroke
- Impaired sensorium
- Obstructive sleep apnea
- Preoperative anemia and/or transfusion
- Preoperative hypoxemia
- Preoperative sepsis
- Preoperative transfusion of >4 units of packed red blood cells
- Pulmonary hypertension
- Respiratory infection within past month
- Weight loss of >10% within six months
Interventions for preventing post-operative pneumonia include213, 214:
- Staff education about their involvement in preventing post-operative pneumonia
- Coughing and deep breathing exercises
- Twice daily oral hygiene with chlorhexidine
- Pain control
- Ambulation as tolerated
- If applicable, head of the bed elevation to at least 30°
- Documentation of interventions and scheduled assessment of their effectiveness
- Chest physiotherapy is not routinely recommended for all postoperative patients at high risk for pneumonia.181
Other prophylactic procedures for prevention of hospital-acquired pneumonia/pneumonia
Antimicrobials are not recommended for preventing pneumonia in critically ill patients or in patients who are mechanically ventilated.215
Selective decontamination of the digestive tract with antiseptics or antibiotics applied to the oropharynx has been shown to reduce the incidence of ventilator-associated pneumonia and hospital-associated pneumonia.180
There is insufficient evidence to recommend glucocorticoids, pro-biotics, or silver-coated endotracheal tubes as effective prophylactic measures.180
Routine turning of the patient or the use of automatically turning beds is not routinely recommended.181