Infection Control in the Intensive Care Unit
infection and if the intensivist is informed about the type of pathogens by which the septic patient is colonised, he could add early and appropriate empirical therapy while waiting for the results from the taken cultures. The collection of cultures for surveillance purposes is not extensively studied and no specific guidelines have been reported regarding the best sites and the frequency to screen. A cost-effective policy has not yet been proved and even if there are several studies reporting the significance of colonisation surveillance programmes it is still not clear if there is a positive impact on mortality rates.17–23 However, surveillance provides an accurate screening method for the detection of patients who are colonised with MDR pathogens at the time of their admission, allowing for early contact and isolation measures to be applied.
Specific Infection Sites Prevention Ventilator-associated Pneumonia
Ventilator-associated pneumonia (VAP) is the most common infection in the ICU leading to increased morbidity and mortality, prolonged hospitalisation in the ICU, increased number of days on mechanical ventilation and prolonged duration of antimicrobial use.
The prevention of VAP is based on general and specific control measures. The general control measures include hand hygiene, surveillance methods performance and staff education. The specific measures include the short duration of ventilation (avoidance of mechanical ventilation if possible, preference of non-invasive ventilation whenever possible, daily efforts to wean), the prevention of aspiration (maintenance of semi-recumbent position, avoidance of gastric overdistention, avoidance of unplanned extubations,
maintenance of endotracheal cuff pressure of at least 20 cm H2O), strategies for the reduction of aerodigestive colonisation (orotracheal
intubation performance, avoidance of H2-blocking agents and proton-pump inhibitors, usage of oral antiseptics and silver-coated endotracheal tubes, use of endotracheal tubes with subglotic aspiration ports) and appropriate cleansing and disinfection of ventilator equipment.
Catheter-related Bloodstream Infections Catheter-related bloodstream infections (CRBSI) reflect a significant cause of infection in the ICU. A significant percentage of those infections can be prevented using the general proposed measures which includes:
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the education of healthcare personnel on indications, insertion procedures and infection control measures (nursing staff adequacy is considered crucial in the CRBSI control as high patient-to-nurse ratios are associated with more CRBSI);
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• • •
the continuous assessment of knowledge and adherence to the guidelines;
surveillance for CRBSI rates, clusters and epidemics;
the routine monitoring for the detection of wrong practices; and feedback and communication of the collected data.
The prevention of CRBSI are focused mainly on the selection of the catheter type and site of insertion, hand hygiene procedures, aseptic techniques and barrier precautions, skin preparations and site dressing regiments and cleansing and surveillance. Upper extremities are preferred for central venous catheter (CVC) insertion, while maximal sterile barrier precautions should be undertaken for the insertion of CVCs (cap, mask, sterile gown, sterile gloves, sterile full-body drape).
EUROPEAN INFECTIOUS DISEASE
The skin preparation should be done with chlorhexidine (>0.5 %) with alcohol before CVC insertion and during dressing changes (tincture of iodine, iodophor, 70 % alcohol as alternatives). Catheter insertion site should be evaluated daily by palpation and visually when changing the dressing, depending on the clinical situation of the individual patient. If patients have tenderness at the insertion site, fever without obvious source, or other manifestations suggesting local or bloodstream infection, the dressing should be removed to allow thorough examination of the site.
Chlorhexidine-impregnated sponge dressing for temporary short-term catheters should be used in patients more than two months old if the CRBSI rate is not decreasing, despite adherence to basic prevention measures. CVCs should not be routinely replaced or removed on the basis of fever alone but only after clinical judgment. Guidewire exchanges should not be used to prevent infection or when infection is suspected but only to replace a malfunctioning non-tunnelled catheter if no evidence of infection is present and always with sterile gloves. Administration sets should be replaced no more frequently than at 96-hour intervals but at least every seven days. Ultrasound guidance to place CVCs (if this technology is available) is associated with a reduction of the number of cannulation attempts and mechanical complications and therefore this technique must be only used by fully trained physicians. The use of a sutureless securement device to reduce the risk of infection for intravascular catheters is allowed, while the use of a chlorhexidine/silver sulfadiazine or minocycline/rifampin-impregnated CVC is recommended in patients whose catheter is expected to remain in place more than five days after successful implementation of a comprehensive strategy to reduce rates of CRBSI if their rate is not decreasing.
Urinary Tract Infections
Urinary tract infections (UTIs) are relatively common in critically ill patients, almost exclusively related to the use of an indwelling urinary catheter or to invasive urinary tract procedures. UTIs include symptomatic UTI, asymptomatic bacteriuria and other infections of the urinary tract. The recognised risk factors for the development of a UTI include female gender, duration of catheterisation, immunodeficiency and length of ICU stay. UTIs are often associated with increased morbidity but not mortality, while the preventive measures currently under investigation include general measures (education of staff concerning the correct techniques of catheter insertion and manipulation, hand hygiene and use of aseptic methods for inserting the catheter and obtaining urine samples), catheterisation only when necessary, maintenance of a closed drainage system, maintenance of unobstructed urine flow and the use of silver-coated catheters. A practice that must be avoided is the use of prophylactic antibiotics. Finally, it is very important to remember that asymptomatic bacteriuria is a distinct condition, which does not need antibiotic treatment, compared to symptomatic UTI.28–31
Clostridium Difficile Infections C. difficile-related diarrhoea is the most common cause of nosocomial diarrhoea, associated with the prior use of antibiotics (mainly clindamycin, b-lactamase inhibitors, third-generation cephalosporins). The severity of diarrhoea varies from mild diarrhoea to fatal pseudomembranous enterocolitis, while treatment includes the use of metronidazole or vancomycin PO, as well as the discontinuation of the causative agent. Precautionary measures include the prevention of ingestion of C. difficile (hand hygiene, isolation of patients),
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