Kathleen McMullen

A Prospective Evaluation of Ventilator-Associated Conditions and Infection-Related Ventilator-Associated Conditions

BACKGROUND The Centers for Disease Control and Prevention has shifted policy away from using ventilator-associated pneumonia (VAP) and toward using ventilator-associated conditions (VACs) as a marker of ICU quality. To date, limited prospective data regarding the incidence of VAC among medical and surgical ICU patients, the ability of VAC criteria to capture patients with VAP, and the potential clinical preventability of VACs are available. METHODS This study was a prospective 12-month cohort study (January 2013 to December 2013). RESULTS We prospectively surveyed 1,209 patients ventilated for ≥ 2 calendar days. Sixty-seven VACs were identified (5.5%), of which 34 (50.7%) were classified as an infection-related VAC (IVAC) with corresponding rates of 7.0 and 3.6 per 1,000 ventilator days, respectively. The mortality rate of patients having a VAC was significantly greater than that of patients without a VAC (65.7% vs 14.4%, P < .001). The most common causes of VACs included IVACs (50.7%), ARDS (16.4%), pulmonary edema (14.9%), and atelectasis (9.0%). Among IVACs, 44.1% were probable VAP and 17.6% were possible VAP. Twenty-five VACs (37.3%) were adjudicated to represent potentially preventable events. Eighty-six episodes of VAP occurred in 84 patients (10.0 of 1,000 ventilator days) during the study period. The sensitivity of the VAC criteria for the detection of VAP was 25.9% (95% CI, 16.7%-34.5%). CONCLUSIONS Although relatively uncommon, VACs are associated with greater mortality and morbidity when they occur. Most VACs represent nonpreventable events, and the VAC criteria capture a minority of VAP episodes.

Use of Hypochlorite Solution to Decrease Rates of Clostridium difficile–Associated Diarrhea

An increased rate of Clostridium difficile-associated diarrhea (CDAD) was noted in 2 intensive care units of a university-affiliated tertiary care facility. One unit instituted enhanced environmental cleaning with a hypochlorite solution in all rooms, whereas the other unit used hypochlorite solution only in rooms of patients with CDAD. The CDAD rates decreased in both units.

Peripherally Inserted Central Venous Catheter–Associated Bloodstream Infections in Hospitalized Adult Patients

BACKGROUND Limited data on the risk of peripherally inserted central venous catheter-associated bloodstream infections (PICC BSIs) in hospitalized patients are available. In 2007, dedicated intravenous therapy nurses were no longer available to place difficult peripheral intravenous catheters or provide PICC care Barnes-Jewish Hospital. OBJECTIVES To determine the hospital-wide incidence of PICC BSIs and to assess the effect of discontinuing intravenous therapy service on PICC use and PICC BSI rates. SETTING A 1,252-bed tertiary care teaching hospital. METHODS A 31-month retrospective cohort study was performed. PICC BSIs were defined using National Healthcare Safety Network criteria. RESULTS In total, 163 PICC BSIs were identified (3.13 BSIs per 1,000 catheter-days). PICC use was higher in intensive care units (ICUs) than non-ICU areas (PICC utilization ratio, 0.109 vs 0.059 catheter-days per patient-day for ICU vs non-ICU; rate ratio [RR], 1.84 [95% confidence interval {CI}, 1.78-1.91]). PICC BSI rates were higher in ICUs (4.79 vs 2.79 episodes per 1,000 catheter-days; RR, 1.7 [95% CI, 1.10-2.61]). PICC use increased hospital-wide after the intravenous therapy service was discontinued (0.049 vs 0.097 catheter-days per patient-day; P =.01), but PICC BSI rates did not change (2.68 vs 3.63 episodes per 1,000 catheter-days; P =.06). Of PICC BSIs, 73% occurred in non-ICU patients. CONCLUSIONS PICC use and PICC BSI rates were higher in ICUs; however, most of the PICC BSIs occurred in non-ICU areas. Reduction in intravenous therapy services was associated with increased PICC use across the hospital, but PICC BSI rates did not increase.

Electronic surveillance for healthcare-associated central line-associated bloodstream infections outside the intensive care unit

BACKGROUND Manual surveillance for central line-associated bloodstream infections (CLABSIs) by infection prevention practitioners is time-consuming and often limited to intensive care units (ICUs). An automated surveillance system using existing databases with patient-level variables and microbiology data was investigated. METHODS Patients with a positive blood culture in 4 non-ICU wards at Barnes-Jewish Hospital between July 1, 2005, and December 31, 2006, were evaluated. CLABSI determination for these patients was made via 2 sources; a manual chart review and an automated review from electronically available data. Agreement between these 2 sources was used to develop the best-fit electronic algorithm that used a set of rules to identify a CLABSI. Sensitivity, specificity, predictive values, and Pearsons correlation were calculated for the various rule sets, using manual chart review as the reference standard. RESULTS During the study period, 391 positive blood cultures from 331 patients were evaluated. Eighty-five (22%) of these were confirmed to be CLABSI by manual chart review. The best-fit model included presence of a catheter, blood culture positive for known pathogen or blood culture with a common skin contaminant confirmed by a second positive culture and the presence of fever, and no positive cultures with the same organism from another sterile site. The best-performing rule set had an overall sensitivity of 95.2%, specificity of 97.5%, positive predictive value of 90%, and negative predictive value of 99.2% compared with intensive manual surveillance. CONCLUSIONS Although CLABSIs were slightly overpredicted by electronic surveillance compared with manual chart review, the method offers the possibility of performing acceptably good surveillance in areas where resources do not allow for traditional manual surveillance.

Identification of a Pseudo‐Outbreak of Clostridium difficile Infection (CDI) and the Effect of Repeated Testing, Sensitivity, and Specificity on Perceived Prevalence of CDI

OBJECTIVE To describe a pseudo-outbreak of Clostridium difficile infection (CDI) caused by a faulty toxin assay lot and to determine the effect of sensitivity, specificity, and repeated testing for C. difficile on perceived CDI burden, positive predictive value, and false-positive results. DESIGN Outbreak investigation and criterion standard. PATIENTS Patients hospitalized at a tertiary care hospital who had at least 1 toxin assay for detection of C. difficile performed during the period from July 1, 2004, through June 30, 2006. METHODS The run control chart method and the chi(2) test were used to compare CDI rates and the proportion of positive test results before, during, and after the pseudo-outbreak. The effect of repeated testing was evaluated by using 3 hypothetical models with a sample of 10,000 patients and various assay sensitivity and specificity estimates. RESULTS In November of 2005, the CDI rate at the hospital increased from 1.5 to 2.6 cases per 1,000 patient-days (P < .01), and the proportion of positive test results increased from 13.6% to 22.1% (P < .01). An investigation revealed a pseudo-outbreak caused by a faulty toxin assay lot. A decrease of only 1.2% in the specificity of the toxin assay would result in a 32% increase in perceived incidence of CDI at this institution. When calculated by use of the manufacturers stated specificity and sensitivity and this institutions testing practices, the positive predictive value of the test decreased from 80.6% to 4.1% for patients who received 3 tests. CONCLUSION Specificity is as important as sensitivity when testing for CDI. False-positive CDI cases can drain hospital resources and adversely affect patients. Repeated testing for C. difficile should be performed with caution.

Patient- and device-specific risk factors for peripherally inserted central venous catheter-related bloodstream infections.

OBJECTIVE To determine the patient- and device-specific risk factors for hospital-acquired peripherally inserted central venous catheter-related bloodstream infections (PICC BSIs) in adult patients. DESIGN Nested case-control study. SETTING Barnes-Jewish Hospital, a 1,252-bed tertiary care teaching hospital. PATIENTS Adult patients with PICCs placed from January 1, 2006, through July 31, 2008. METHODS PICC BSI cases were identified using the National Healthcare Safety Network definition. Uninfected control patients with PICCs in place were randomly selected at a 3∶1 ratio. Patient- and device-related variables were examined using multivariate analysis. RESULTS The overall PICC BSI rate was 3.13 per 1,000 catheter-days. Independent risk factors for PICC BSIs included congestive heart failure (odds ratio [OR], 2.0 [95% confidence interval (CI), 1.26-3.17]; P = .003), intra-abdominal perforation (OR, 5.66 [95% CI, 1.76-18.19]; P = .004), Clostidium difficile infection (OR, 2.25 [95% CI, 1.17-4.33]; P = .02), recent chemotherapy (OR, 3.36 [95% CI, 1.15-9.78]; P = .03), presence of tracheostomy (OR, 5.88 [95% CI, 2.99-11.55]; P < .001), and type of catheter (OR for double lumen, 1.89 [95% CI, 1.15-3.10]; P = .01 ; OR for triple lumen, 2.87 [95% CI, 1.39-5.92]; P = .004). Underlying chronic obstructive pulmonary disease (OR, 0.48 [95% CI, 0.29-0.78]; P = .03) and admission to surgical (OR, 0.43 [95% CI, 0.24-0.79]; P = .006) or oncology and orthopedic (OR, 0.35 [95% CI, 0.13-0.99]; P = .05) services were less likely to be associated with having a PICC BSI. CONCLUSIONS We identified several novel factors related to PICC BSIs. These factors may inform preventive measures.

The changing susceptibilities of methicillin-resistant Staphylococcus aureus at a midwestern hospital: The emergence of “community-associated” MRSA

BACKGROUND The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been well described; however, few studies have reviewed long-term hospital-wide data. METHODS This retrospective study of adult patients used the first culture per patient per visit positive for MRSA for 1996 to 2005. Isolates were categorized as community-associated or health care-associated phenotype based on antibiotic susceptibilities. chi(2) tests for trend and linear regression analyses were performed. RESULTS The annual prevalence of CA-MRSA increased significantly over the 10-year study period (from 43 of 507 [8.9%] MRSA cultures in 1996 to 672 of 1697 [39.6%] MRSA cultures in 2005; P < .01). The proportion of MRSA cultures obtained within 48 hours of hospital admission increased from 50.5% to 79.5% (P < .01). The median age of patients with MRSA decreased, from 60 to 49 years (P < .01). Among the CA-MRSA cases, the proportion of non-Caucasian patients increased from 30.2% to 60.4% (P < .01) and the proportion of patients categorized as low socioeconomic status increased from 25.6% to 35.6% (P < .01). Significant consistent trends were not observed for patient sex or body sites of the cultures. CONCLUSION An increasing number of MRSA with a community-associated phenotype occurred during the 10-year study period. Patterns of decreasing age, increasing non-Caucasian races, and decreasing socioeconomic status were observed among patients with MRSA.

Hospital-Associated Clostridium difficile Infection : Is It Necessary to Track Community-Onset Disease?

OBJECTIVES To compare Clostridium difficile infection (CDI) rates determined with use of a traditional definition (ie, with healthcare-onset CDI defined as diagnosis of CDI more than 48 hours after hospital admission) with rates determined with use of expanded definitions, including both healthcare-onset CDI and community-onset CDI, diagnosed within 48 hours after hospital admission in patients who were hospitalized in the previous 30 or 60 days, and to determine whether differences exist between patients with CDI onset in the community and those with CDI onset in a healthcare setting. DESIGN Prospective cohort. SETTING Tertiary acute care facility. PATIENTS General medicine patients who received a diagnosis of CDI during the period January 1, 2004, through December 31, 2005. METHODS CDI was classified as healthcare-onset CDI, healthcare facility-associated CDI after hospitalization within the previous 30 days, and/or healthcare facility-associated CDI after hospitalization within the previous 60 days. Patient demographic characteristics and medication exposures were obtained. The CDI incidence with use of each definition, CDI rate variability, patient demographic characteristics, and medication exposures were compared. RESULTS The healthcare-onset CDI rate (1.6 cases per 1,000 patient-days) was significantly lower than the 30-day healthcare facility-associated CDI rate (2.4 cases per 1,000 patient-days; P< .01) and the 60-day healthcare facility-associated CDI rate (2.6 cases per 1,000 patient-days; P< .01). There was good correlation between the healthcare-onset CDI rate and both the 30-day (correlation, 0.69; P< .01) and 60-day (correlation, 0.70; P< .01) healthcare facility-associated CDI rates. There were no months in which the CDI rate was more than 3 standard deviations from the mean. Compared with patients with healthcare-onset CDI, patients with community-onset CDI were less likely to have received a fourth-generation cephalosporin (P= .02) or intravenous vancomycin (P+ .01) during hospitalization. CONCLUSIONS Compared with the traditional definition, expanded definitions identify more patients with CDI. There is good correlation between traditional and expanded CDI definitions; therefore, it is unclear whether expanded surveillance is necessary to identify an abnormal change in CDI rates. Cases that met the expanded definitions were less likely to have occurred in patients with fourth-generation cephalosporin and vancomycin exposure.

Surveillance versus clinical adjudication: Differences persist with new ventilator-associated event definition

BACKGROUND The National Healthcare Safety Network (NHSN) has recently supported efforts to shift surveillance away from ventilator-associated pneumonia to ventilator-associated events (VAEs) to decrease subjectivity in surveillance and minimize concerns over clinical correlation. The goals of this study were to compare the results of an automated surveillance strategy using the new VAE definition with a prospectively performed clinical application of the definition. METHODS All patients ventilated for ≥2 days in a medical and surgical intensive care unit were evaluated by 2 methods: retrospective surveillance using an automated algorithm combined with manual chart review after the NHSNs VAE methodology and prospective surveillance by pulmonary physicians in collaboration with the clinical team administering care to the patient at the bedside. RESULTS Overall, a similar number of events were called by each method (69 vs 67). Of the 1,209 patients, 56 were determined to have VAEs by both methods (κ = .81, P = .04). There were 24 patients considered to be a VAE by only 1 of the methods. Most discrepancies were the result of clinical disagreement with the NHSNs VAE methodology. CONCLUSIONS There was good agreement between the study teams. Awareness of the limitations of the surveillance definition for VAE can help infection prevention personnel in discussions with critical care partners about optimal use of these data.

Chlorhexidine Gluconate Bathing to Reduce Methicillin-Resistant Staphylococcus aureus Acquisition

BACKGROUND Methicillin-resistant Staphylococcus aureus (MRSA) is a virulent organism causing substantial morbidity and mortality in intensive care units. Chlorhexidine gluconate, a topical antiseptic solution, is effective against a wide spectrum of gram-positive and gram-negative bacteria, including MRSA. Objectives To examine the impact of a bathing protocol using chlorhexidine gluconate and bath basin management on MRSA acquisition in 5 adult intensive care units and to examine the cost differences between chlorhexidine bathing by using the bath-basin method versus using prepackaged chlorhexidine-impregnated washcloths. METHODS The protocol used a 4-oz bottle of 4% chlorhexidine gluconate soap in a bath basin of warm water. Patients in 3 intensive care units underwent active surveillance for MRSA acquisition; patients in 2 other units were monitored for a new positive culture for MRSA at any site 48 hours after admission. RESULTS Before the protocol, 132 patients acquired MRSA in 34333 patient days (rate ratio, 3.84). Afterwards, 109 patients acquired MRSA in 41376 patient days (rate ratio, 2.63). The rate ratio difference is 1.46 (95% CI, 1.12-1.90; P = .003). The chlorhexidine soap and bath basin method cost