SPECIFIC INFECTIONS

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.

• 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.

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.

2. 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.

3. 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.

4. Use of probiotics

There are few data to support the use of probiotics and currently it is not recommended as a prevention measure.

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.