Ventilator-Associated Pneumonia

The 2005 American Thoracic Society/Infectious Diseases Society of America guidelines defined hospital-acquired pneumonia (HAP) as pneumonia that occurs at least 48 hours after admission to the hospital. VAP is a type of HAP that develops more than 48 hours after endotracheal intubation. Intubation increases the risk of pneumonia 6- to 21-fold, and VAP occurs in 9% to 27% of all intubated patients with 2.1 to 10.7 episodes of VAP per 1000 ventilator days. VAP is the leading cause of mortality from ICU-acquired infections. Patients with VAP are twice as likely to die compared with those without VAP, with a crude mortality rate that exceeds 30% if a high-risk pathogen is involved. Several reports have shown that patients who develop VAP have an increase in ICU stay of 4.3 to 13 extra days and an increase in costs with each case of VAP ($12,000 to $40,000).
The most significant risk factor for HAP is mechanical ventilation, which is an inherent component to the development of VAP. A risk factors review by Safdar and colleagues revealed that postsurgical patients, presence of multiple organ failure, age greater than 60 years, supine patient positioning, decreased gastric pH, cardiopulmonary resuscitation, continuous sedation, reintubation, presence of nasogastric tube, enteral feeding, sinusitis, and patients transported out of the ICU had increased risk of developing VAP.
Owing to the high morbidity and mortality and economic impact of this condition, the implementation of preventive measures is paramount in the care of mechanically ventilated patients. There is clear evidence that these measures decrease the incidence of VAP and improve outcomes in ICUs. A multidisciplinary approach, continued education, and ventilator protocols ensure the implementation and compliance with these measures. The current evidence-based preventative measures are as follows.
Non-pharmacologic strategies
  • Avoiding intubation and reintubation when possible. Early extubation when appropriate is the most effective preventive intervention for VAP.
  • Noninvasive ventilation should be used whenever appropriate in selected patients with respiratory failure. Patients with chronic obstructive pulmonary disease and congestive heart failure are more likely to benefit from noninvasive ventilation as a temporary support measure.
  • Use of oral endotracheal and orogastric tubes, rather than nasotracheal and nasogastric tubes. Nasotracheal intubation has been associated with nosocomial sinusitis and high incidence of VAP. The oropharyngeal route is recommended.
  • Continuous aspiration of subglottic secretions. The endotracheal tube stents the epiglottis open and prevents its closure. Oropharyngeal secretions accumulate above the endotracheal tube cuff, below the glottis. Microorganisms can grow in this protected environment. Suction removal of these fluids can reduce the risk of aspiration. Suctioning prior to repositioning or extubation should be standard protocol.
  • Postural drainage, standardized endotracheal suctioning, and use of closed suction system (CSS). Standardized endotracheal suction protocols, in which everyone suctions effectively in the same way, have been shown to reduce colonization and the incidence of VAP. CSS provides a barrier to separate the contaminated catheter from the caregiver, hence other patients, as well as reducing the environmental exposure of the patient being suctioned. Moreover, closed suctioning also permits continuous ventilation, reducing respiratory stress and vulnerability.
  • Maintaining endotracheal cuff pressure at greater than 20 cm H2O. A cuff that is underinflated forms creases that can readily allow contaminated secretions to migrate past the cuff and aspirate into the lungs. On the other hand, excessive inflation and too much pressure can prevent adequate perfusion of contacted mucosa and damage tissue. The optimal pressure for all situations has not been conclusively established but is generally held to be 20 mm Hg. Cuff pressure should be monitored and recorded routinely.
  • Semirecumbent positioning of the patients, especially when they are enterally fed. The supine position increases the accumulation of secretions in the subglottic area. Elevating the head 30_ to 45_ reduces this pooling and thus the microbial load and contamination pressure and has been shown to decrease the VAP rate.
  • Alcohol-based hand disinfection and use of protective gowns and gloves prevents horizontal patient-to-patient contamination and acquiring VAP and infections in general.
  • Staff education and compliance with isolation procedures has been shown to reduce cross-infection with multidrug resistance and VAP incidence rate.
Pharmacologic strategies
  • Chlorhexidine oral rinse. Routine oral decontamination is an effective method for reducing VAP by decreasing the contamination pressure and microbial load in the oropharyngeal cavity. It has been found that the incorporation of routine oral hygiene into standard practice reduced VAP by 57.6%. Oral hygiene programs should consist of frequent tooth brushing, oral suctioning and swabbing of the mouth with chlorhexidine antiseptic agents.
  • Limiting the use of sedative and neuromuscular blockers. The use of the least amount of sedation possible has been shown to decrease the duration of delirium in the ICU, number of ventilated days, and mortality.


Intravascular catheters are indispensable in modern-day medical practice, particularly in ICU settings. In the United States, 15 million CVC days occur in ICUs each year (ie, the total number of days of exposure to CVCs by all patients in the selected population during the selected time period). Although these catheters are useful a clinical tool, Infection Control in the Intensive Care Unit 1179 their use puts patients at risk for local and systemic infectious complications, including local site infections, CLABSIs, and distant metastatic infections. CLABSIs are important cause of morbidity and attributable mortality, estimated to be 12% to 25% for each infection episode. The prevalence of CLABSIs in the ICU has yet to be determined, but in the United States, it has been estimated that there are approximately 80,000 CLABSIs per year in ICUs. This number has been declining, however, with the widespread efforts of prevention. In United States ICUs, CLABSI incidence has decreased from 3.64 to 1.65 infections per 1000 central line days between 2001 and 2009. The total cost of CLABSIs per year in the United States has been estimated at between $0.67 and $2.68 billion.
The incidence of CLABSIs varies considerably by catheter-related factors and patient related factors.
Patient-related factors:
  • Malnutrition
  • Total parenteral nutrition administration
  • Previous bloodstream infection
  • Extremes of age
  • Loss of skin integrity, as with burns
  • Immune deficiency, especially neutropenia
  • Chronic illness
  • Bone marrow transplantation
Catheter-related factors
  • Location of catheter insertion (higher risk with femoral or internal jugular more than subclavian)
  • Insertion technique (higher risk with non-tunneled compared with tunneled insertion, and tunneled insertion compared with a totally implantable device)
  • Long duration of catheterization (the older the line the higher the risk, although there is no indication for routine line changing based on number of catheter days)
  • Conditions of insertion (higher risk with submaximal compared with maximal barrier precautions during insertion [ie, mask, cap, sterile gloves, gown, large drape])
  • Catheter-site care (emergency compared with elective, unskilled compared with skilled inserter)
  • Indication and use (higher risk with catheters used for hyper-alimentation or hemodialysis compared with other indications)
Catheter material type (higher risk with bare catheters compared with antibiotic impregnated catheters.
  • Compliance with hand hygiene measures. It is critical to observe proper hand hygiene procedures either by washing hands with conventional antiseptic-containing soap and water or with waterless alcohol-based gels or foams. This should be maintained before and after palpating catheter insertion sites as well as before and after inserting, replacing, accessing, repairing, or dressing an intravascular catheter. Use of gloves does not obviate hand hygiene.
  • Use an all-inclusive catheter cart or kit.
  • Use maximal sterile barrier precautions during CVCinsertion, including a full-body drape over the patient, mask, cap, sterile gloves, and gown.
  • Use a 2% chlorhexidine-based antiseptic for skin preparation in patients older than 2 months. In adults, although a 2% chlorhexidine-based preparation is preferred, tincture of iodine, an iodophor, or 70% alcohol can be used.
  • In adults, referentially use the subclavian vein for placement of CVC, unless contraindicated. Studies in children have demonstrated that femoral catheters have a low incidence of mechanical complications and might have an infection rate similar to that of non-femoral catheters.
  • The type of catheter selected should depend on its intended purpose and duration of use, risks and benefits of the particular catheter, and experience of the catheter operators.
  • The use of dynamic 2-D ultrasound for the placement of CVCs has been shown in 2 meta-analyses to substantially reduce mechanical complications and decrease the number of attempts required to successfully cannulate the vein.
  • Disinfect catheter hubs, needleless connectors, and injection ports before accessing the catheter. Cap all stopcocks when not in use.
  • Frequently assess the need to keep intravascular catheters and promptly remove any catheter that is no longer essential. Do not routinely replace CVCs, peripherally inserted central catheters (PICCs), hemodialysis catheters, or pulmonary artery catheters to prevent catheter-related infections. Do not remove CVCs or PICCs on the basis of fever alone. Use clinical judgment regarding the appropriateness of removing the catheter if infection is evidenced elsewhere or if a noninfectious cause of fever is suspected.
  • Replace administration sets not used for blood, blood products, or lipids at intervals not longer than 96 hours.
  • Topical antibiotic ointment or creams should not be used on the insertion site, except for dialysis catheters, because of their potential to promote fungal infection and antimicrobial resistance.
  • Systemic antibiotics should not be administered as prophylaxis either before insertion or during use on an intravascular catheter to prevent catheter colonization or RBSI.
Last but not least, it is essential to educate and periodically assess adherence of all ICU staff with the indications for intravascular catheter use, proper procedures for the insertion and maintenance of intravascular catheters, and appropriate infection control measures to prevent intravascular catheter-related infections.


Since 1978, when it was first identified as the cause of pseudomembranous colitis, C difficile has become the most common cause of nosocomial infectious diarrhea. CDI is also the most frequent cause of ICU-acquired infectious diarrhea. The incidence and severity of CDI are increasing prompting more admissions to ICUs for management of CDI-related complications. CDI has been associated with an attributable mortality rate of 6.9% at 30 days and 16.7% at 1 year after diagnosis.
ICU stay has been commonly cited as a risk factor for CDI. The other risk factors that are most consistently identified in the literature include antibiotic exposure, age Infection Control in the Intensive Care Unit greater than 60 years, longer duration of hospital stay, severe underlying disease, and gastric acid suppression.167 Exposure to antimicrobials is the most important risk factor for the development of CDI with broad-spectrum antibiotics the most common offenders.
Pathogen transmission between patients and health care professionals is a major source of CDI infection in the ICU. Therefore, the most essential aspect of CDI prevention is protecting patients from initial acquisition of the organism in the health care setting. The prevention strategies are divided into 4 categories: (1) measures for health care workers, patients, and visitors; (2) environmental cleaning and disinfection; (3) antimicrobial use restrictions; and (4) use of probiotics.
  1. Measures for health care workers, patients, and visitors
  • Strict use of gowns and gloves on entry into room of patient infected with C difficile is the most effective single preventive measure.
  • All health care workers must follow meticulous hand hygiene protocols. In nonoutbreak settings, hand hygiene with alcohol-based hand sanitizers, in addition to wearing gloves as a component of contact precautions, is considered an acceptable method of hand hygiene after caring for patients with CDI. In outbreak settings, however, preferential use of soap and water is recommended after caring for a patient with CDI because of the theoretic increase in risk of C difficile transmission.
  • Educate health care personnel, housekeeping personnel, and hospital administration about CDI.
  • Educate patients and their families about CDI and contact precautions.
  1. Environmental cleaning and disinfection
  • Patients with CDI should be accommodated in private rooms with contact precautions.
  • Chlorine-containing cleaning agents or other sporicidal agents should be used in cleaning ICU rooms.
  • Each patient in isolation should have dedicated equipment, such as stethoscopes and blood pressure cuffs.
  1. Antimicrobial use restrictions
  • Minimize the frequency and duration of antimicrobial therapy and the number of antimicrobial agents prescribed, to reduce CDI risk.
  • Implement an antimicrobial stewardship program. Antimicrobials to be targeted should be based on the local epidemiology and the C difficile strains present, but restricting the use of cephalosporin and clindamycin (except for surgical antibiotic prophylaxis) may be particularly useful.
  1. Use of probiotics
There are few data to support the use of probiotics and currently it is not recommended as a prevention measure.


Nosocomial urinary tract infections (UTIs) account for up to 40% of infections in hospitals and 23% of nosocomial infections in ICUs. A vast majority of UTIs are related to indwelling urinary catheters, with 95% of UTIs occurring in ICUs developing in patients with urinary catheters. Nosocomial UTIs have been associated with a 3-fold increased risk for mortality in hospital-based studies, with estimates of more than 50,000 excess deaths occurring per year in the United States as a result of these infections. CAUTIs result in as much as $131 million excess direct medical costs nationwide annually. Since October 2008, the Centers for Medicare and Medicaid Services no longer reimburses hospitals for the extra costs of managing patients with hospital-acquired CAUTI. Prevention has become a priority for most hospitals, because 65% to 70% of CAUTIs are estimated to be preventable.
Duration of catheterization is the most important risk factor for CAUTIs. Up to 95% of UTIs in ICUs are associated with an indwelling urinary catheter. Bacteruria, the precursor to CAUTI, develops quickly at an average daily rate of 3% to 10% per day of catheterization. Almost 26% of patients with a catheter in place for 2 to 10 days develop bacteruria, and virtually all patients catheterized for 1 month develop bacteruria. Non-modifiable patient-related risk factors include female gender, severe underlying illness, nonsurgical disease, age greater than 50 years, diabetes mellitus, and serum creatinine level greater than 2 mg/dL. The modifiable risk factors are duration of catheterization, adherence to aseptic catheter care, catheter insertion after the sixth day of hospitalization, and catheter insertion outside the operating room.
Avoid insertion of indwelling urinary catheters when possible. The most effective strategy for CAUTI prevention is limitation or avoidance of catheterization as appropriate. The first step toward achieving this goal is through restricting urinary catheter placement to appropriate indications and activating institutional protocols that reinforces this procedure.
Early removal of indwelling catheters. Checklists, daily plans, nurse-based interventions, and electronic reminders were all found effective at reducing duration of catheterization and hence the rate of UTI per 10,000 patient-days.
Seek alternatives to indwelling catheterization when appropriate. Intermittent catheterization and condom catheter are good alternatives. Compared with indwelling urinary catheterization, intermittent urinary catheterization reduces the risk of bacteruria and UTI. Moreover, condom catheters can be considered in appropriately selected male patients without urinary retention, dementia, or bladder outlet obstruction. A randomized trial demonstrated a decrease in bacteruria, symptomatic UTI, and death in patients with condom catheters compared with those with indwelling catheter.
Proper techniques for insertion and maintenance of catheters are essential preventative measures. All urinary catheters should be inserted by a trained health care professional using aseptic technique and connected to a closed drainage system.
Avoidance of routine bladder irrigation. Prophylactic instillation of antiseptic agents or irrigation of the bladder with antimicrobial or antiseptic agents has been shown to increase infection and is not recommended.

Ref: Mohamed F. Osman, Infection Control in the Intensive Care Unit, Surg Clin N Am 94 (2014) 1175–1194