Helen Rosen Kotilainen

Intracranial pressure monitors. Epidemiologic study of risk factors and infections

An increase in the number of cases of gram-negative ventriculomeningitis in patients followed with intracranial pressure monitors when compared with patients with craniotomy alone was revealed by routine surveillance data. A study was undertaken at four area institutions to describe the infections, risk factors, and management. Two hundred fifty-five patients with diagnoses of intracerebral hemorrhage (n = 86), closed trauma (n = 66), open trauma (n = 21), tumor (n = 66), and miscellaneous other conditions were compared with their nonmonitored counterparts for type of intracranial pressure monitor used, use of drains, prophylactic antibiotics, and steroids, and remote presence of infection. The presence of intracranial pressure monitor with craniotomy was associated with an 11 percent infection rate whereas craniotomy alone demonstrated a 6 percent rate. Of the intracranial pressure monitors used, the subarachnoid screw was associated with the lowest infection rate (7.5 percent) followed by the subdural cup catheter (14.9 percent) and the ventriculostomy catheter (21.9 percent). Regardless of the monitor used, infection was twice as likely to develop in patients with open trauma or hemorrhage. The use of bacitracin flush solutions for maintenance of lumen patency was more often associated with infections. Use of prophylactic antibiotics did not significantly influence outcome.

Clostridium difficile-associated diarrhea: epidemiology, risk factors, and infection control.

OBJECTIVES To evaluate the effectiveness of specific infection control measures on the incidence of Clostridium difficile-associated diarrhea (CDAD) and to identify risk factors for its development. SETTING 370-bed, tertiary-care teaching hospital with approximately 12,000 to 15,000 admissions per year. METHODS Several infection control measures were implemented in 1991 and 1992, and the attack rates of CDAD were calculated quarterly. Antibiotic use for 1988 through 1993 was analyzed. A case-control study was conducted from January 1992 to December 1992 to identify risk factors for acquisition of CDAD. RESULTS From 1989 to 1992, the attack rate of CDAD increased from 0.49% to 2.25%. An increase in antibiotic use preceded the rise in the incidence of CDAD in 1991. Despite implementation of various infection control measures, the attack rate decreased to 1.32% in 1993, but did not return to baseline. Ninety-two cases and 78 controls (patients with diarrhea but with negative toxin assay) were studied. By univariate analysis, history of prior respiratory tract infections (odds ratio [OR], 3.6; 95% confidence interval [CI95], 1.2-10.4), the number of antibiotics, and the duration of exposure to second-generation cephalosporins (OR, 3.55; CI95, 1.47-9.41) and to ciprofloxacin (OR, 7.27; CI95, 1.13-166.0) were related significantly to the development of CDAD. By stepwise logistic regression analysis, only exposure to antibiotics and prior respiratory tract infections (P = .0001 and .0203, respectively) were found to be significant. CONCLUSION Antibiotic pressure might have contributed to failure of infection control measures to reduce the incidence of CDAD to baseline.

Latex and Vinyl Examination Gloves: Quality Control Procedures and Implications for Health Care Workers

In December 1987, we investigated an increased number of cases of herpetic whitlow in medical intensive care unit nurses who routinely gloved for secretion contact. One particular brand of vinyl examination glove had been used in the medical intensive care unit. Restriction endonuclease mapping established the similarity of employee isolates with one patient isolate of herpes simplex virus type I. When initial viral assay demonstrated 2.5% to 10% penetration of herpes simplex virus type I across unused gloves, an evaluation of glove quality was undertaken. In a 300-mL watertightness test, seven brands of vinyl gloves failed 4% to 28% (average, 11.1%; 132/1200), while seven brands of latex gloves failed 0% to 2.6% (average, 1.4%; 24/1750). The brand of vinyl glove that had been in use in the medical intensive care unit failed 28% of the time. Watertight gloves were then tested for permeability to herpes simplex virus type I. None of the latex gloves failed (n = 1726), while only 10 of the vinyl gloves failed (n = 1068, 0.95%). Extreme variability in glove quality was observed. However, gloves made from intact vinyl may provide similar protectiveness as those made from intact latex. As the demand for gloves increases, emphasis should be placed on the production of plentiful, better quality latex and vinyl gloves.

Cost analysis and clinical impact of weekly ventilator circuit changes in patients in intensive care unit

BACKGROUND The introduction of heated circuits and sealed, single-use humidifiers has prompted some investigators to question the traditional recommendations for changing ventilator circuits. We studied the clinical and cost impact of extending the circuit change interval from 72 hours to 7 days in our two intensive care units with 17 beds. METHODS With standard surveillance definitions from the Centers for Disease Control and Prevention and the National Nosocomial Infections Surveillance System, baseline pneumonia rates were established for a 3-month period. After the institution of weekly circuit changes, daily surveillance of intubated patients was performed during 18 of 22 weeks from May through September 1993. Standard microbiologic methods were used for the identification of patient and environmental isolates. RESULTS Ventilator-associated pneumonia for the 72-hour circuit change group was 9.1% or 1.29 per 100 ventilator days. After the institution of weekly changes, pneumonia occurred in 9 of 146 patients (6.2% or 0.74 per 100 ventilator days chi 2 = 0.33, p = 0.44). No common bacterial isolates were recovered as judged by phenotype, biochemical, or antimicrobial susceptibility patterns. Weekly changes reduced the number of circuits used from a predicted 469 to 214. Estimating

Biological Sterilization Monitors: A Four-Year In-Use Evaluation of Two Systems

26.46 per circuit change, annualized cost savings were

Study of the Definition of Nosocomial Infections (SDNI)

20,246.90. CONCLUSIONS Weekly circuited changes in patients undergoing ventilation therapy in the intensive care unit are cost-effective and do not contribute to increased rates of nosocomial pneumonia.

Prevention and control of nosocomial infections. 2nd ed

Biological monitors (BI) are considered to be the best monitor of the sterilization process yet false positives may result in recalls and quality assurance difficulties. To assess the frequency, type and reasons for questionable results, we undertook a 4-year in-use study of two commonly used BI types--spore strips (Spordi) and a self-contained crushable ampule (Attest)--for both steam and ethylene oxide (EO). After laboratory verification of time/kill ratios for a portion of each involved lot, 2 BI of each type were placed in test pack within a randomly selected load run at standard time and temperature. All resulting positive BI were subcultured. Steam cycle positives were uncommon (32/1,1710 positive Spordi, 1.9%; 20/1,710 positive Attest, 1.2%) and could be related to chamber temperature or steam quality. All of the 4 BI per load were positive in only three loads; physical monitors indicated gross malfunction. Five positive Spordi were due to either contaminants or a malfunctioning incubator. EO-related positives were more common (53/1,109 positive Spordi, 4.8%; 25/1,109 positive Attest, 2.3%). One-half of the Spordi tests became positive after 48 hours of incubation. Organisms other than B. subtilis were recovered from 49.1% of the positive tests (26/53). The Attest was remarkable for its lack of contamination; 1/25 was positive for Pseudomonas stutzeri only. More positives were observed during the winter months when relative humidity was below 20%. This finding was more commonly observed with the EO Attest. In summary, we found no significant difference in the performance of either BI.(ABSTRACT TRUNCATED AT 250 WORDS)