The ability of Pseudomonas aeruginosa to secrete specific toxins using the type III-mediated pathway has been reported. To determine the association of this phenotype with human illness, immunoblot analysis was used to detect expression of type III secretory proteins in P. aeruginosa isolates from respiratory tract or blood cultures of 108 consecutive patients. Relative risk of mortality was 6-fold greater with expression of the type III secretory proteins ExoS, ExoT, ExoU, or PcrV. Phenotype was independently correlated with toxicity in cellular and murine models. Prevalence of this phenotype was significantly higher in acutely infected patients than in chronically infected patients with cystic fibrosis. These results suggest that the type III protein secretion system is integral to increased P. aeruginosa virulence. A positive phenotype is a predictor of poor clinical outcome. In the future, such analyses may help distinguish potentially lethal infection from colonization and help determine appropriate therapy for critically ill patients.

Non-invasive measurement of intracranial pressure can be invaluable in the management of critically ill patients. We performed a comprehensive review of the literature to evaluate the different methods of measuring intracranial pressure. Several methods have been employed to estimate intracranial pressure, including computed tomography, magnetic resonance imaging, transcranial Doppler sonography, near-infrared spectroscopy, and visual-evoked potentials. In addition, multiple techniques of measuring the optic nerve and the optic nerve sheath diameter have been studied. Ultrasound measurements of the optic nerve sheath diameter and Doppler flow are especially promising and may be useful in selected settings.

Indwelling urinary and central venous catheters are commonly used in the care of critically ill patients. Though both types of devices provide important clinical benefits, they are also the leading causes of nosocomial infection in the intensive care unit (ICU). Enhancing the safety of critically ill patients requires that critical care specialists be aware of the proven methods for preventing urinary catheter-related and central venous catheter-associated infection. To this end, we provide a concise evidence-based overview of preventive methods for both urinary and central venous catheter-related infection. The objective of this update is to consider the evidence supporting specific preventive methods, devoting more attention to recently evaluated interventions and to interventions that many consider controversial (e.g., silver alloy urinary catheters, antimicrobial central venous catheters). Several recent evidence-based reviews provide additional details about the risk factors, microbiology, and pathophysiology of each infection, and provide a more comprehensive review of all the potential preventive methods (1-3). This review is derived from the evidence report produced by the Evidence-Based Practice Center at the University of California at San Francisco-Stanford University, under contract with the Agency for Healthcare Research and Quality (4, 5). URINARY CATHETER-RELATED INFECTIONSCatheter-related urinary tract infection (UTI) is the most common nosocomial infection seen in medical ICUs in the U.S., accounting for 31% of nosocomial infections (6). The daily incidence of bacteriuria in catheterized patients is approximately 3-10% (7). Among patients with bacteriuria, up to 25% will develop symptoms of local UTI, and about 3% will develop bacteremia (7). Each episode of hospital-acquired symptomatic catheter-related UTI costs an additional US $676, and each episode of catheter-related nosocomial bacteremia costs a minimum of US $2,836 (7).The best strategy to prevent nosocomial UTI is to avoid catheterization. Unfortunately, unjustified and excessively prolonged catheter use is common, even in the critically ill (8). Jain and coworkers found that initial catheter insertion was unjustified in 13% of 135 catheterized patients in a medical ICU; continued catheter use was deemed inappropriate for 41% of catheterized patient-days (8). The most common reason for inappropriate catheter use among these medical ICU patients was for close monitoring of urine output; however, the investigators found that often there was no longer a clinically appropriate indication for close urine output monitoring or that an indwelling catheter was not required for this purpose (8). Closed Drainage Systems and Use of Aseptic Insertion TechniquesThe use of proper insertion and maintenance techniques is paramount. The most important infection control advance in urinary catheter-related infection prevention was the introduction approximately four decades ago of the closed catheter drainage system. Maintenance of a closed system includes ...