Evaluating Approaches for the Diagnosis of Hemodialysis Catheter–Related Bloodstream Infections

Abstract

Background and objectives Guideline-recommended diagnostic criteria for hemodialysis (HD) catheter-related bloodstream infections (CRBSIs) are based on data from indwelling central catheters in patients not on HD and non-HD situations, and upon which peripheral vein cultures are the gold standard. We aimed to examine the validity of these criteria in patients on HD.Design, settings, participants, & measurements Adult patients on in-center HD using catheters were prospectively followed from 2011 to 2014 at a large academic-based HD facility (Toronto, Canada). When a CRBSI was suspected, blood culture sets were obtained from four sites (peripheral vein, both catheter hubs, and HD circuit) to determine the guideline-recommended differential time to positivity (DTTP). DTTP criteria were met when catheter hub cultures turned positive $120 minutes before peripheral vein cultures. The sensitivity, specificity, and accuracy were first calculated using peripheral vein cultures as the gold standard and then these same calculations were repeated with additional information, including exit site/catheter tip and HD circuit cultures, as the true gold standard. The feasibility of obtaining peripheral vein cultures was determined.Results Of 178 suspected CRBSIs, 100 had peripheral vein blood cultures. Using the true gold standard, sensitivity, specificity, and accuracy of blood culture results were highest in samples from the HD circuit (93.5%, 100%, and 95%, respectively). The guideline recommended combination of peripheral vein and arterial hub blood cultures was the least sensitive, specific, and accurate (91.7%, 93.1%, and 92.7%, respectively). The diagnostic criteria using measured DTTP were met in less than one third of events.Conclusions In patients on HD, blood culture results are the most sensitive, specific, and accurate for diagnosing CRBSIs when taken from the HD circuit and the venous catheter hub, and blood culture results are the least sensitive, specific, and accurate in any combination with peripheral vein cultures. The DTTP does not increase diagnostic accuracy, reducing the necessity for venipuncture and its potential vein damage. Future guidelines should consider the applicability of criterion on specific patient populations and tailor them accordingly.

Catheter-related blood stream infections in hemodialysis patients: a prospective cohort study

“…poor peripheral venous access, preserving veins for fistula and uncertainty of the value of differential time to positivity when cultures are drawn after the systemic blood has circulated through the catheter), we used a definition of CRBSI that is appropriate for outpatient HD practice. Our chosen definition is also valid, Pelletier et al [ 25 ] showed that compared with blood cultures from the dialysis circuit and the catheter hub, an additional culture from the peripheral vein did not improve the accuracy, sensitivity, or specificity of CRBSI diagnosis. In addition, to minimize error in misdiagnosing CRBSI, we used an adjudication process with clearly defined criteria.…”

Hemodialysis Tunneled Catheter-Related Infections

“…A recent prospective study of 178 suspected CRBSIs in hemodialysis patients showed that blood culture results are the most sensitive, specific, and accurate for diagnosis when taken from the hemodialysis circuit and the venous catheter hub, compared with any combination with peripheral vein cultures. 38 Broad-spectrum antibiotics should be initiated to cover both gram-positive and gram-negative organisms. 14 Antibiotics should generally cover methicillin-resistant S aureus (MRSA) and Pseudomonas but are also dictated by local infection rates, dialysis center policies, and center-specific antimicrobial resistance patterns.…”

Bacteremia in hemodialysis patients

“…A report from Canada indicated that blood cultures drawn from a hemodialysis circuit were the most sensitive, specific, and accurate for diagnosing CRBSIs when all culture data and clinical information were factored into the assessment[32]. For the hemodialysis circuit, the values for sensitivity, specificity, and accuracy were 93.5%, 100% and 95%, respectively, whereas peripheral veins had a sensitivity of 93.9%, a specificity of 92.5%, and an accuracy of 93%.…”