Biomedical subjects

Amy Barton Pai

Publications and source records attributed to Amy Barton Pai.

4 recordsLinked to original sources

PubMed2006

Non-transferrin-bound iron is associated with enhanced Staphylococcus aureus growth in hemodialysis patients receiving intravenous iron sucrose.

BACKGROUND: Hemodialysis vascular access infections are most frequently caused by Staphylococcus spp. The purpose of this study was to determine if S. aureus growth is enhanced after administration of IV iron sucrose and to establish a relationship between the appearance of non-transferrin-bound iron (NTBI) and S. aureus growth. METHODS: Serum samples were obtained from 12 hemodialysis patients receiving maintenance doses of 100 mg of iron sucrose at baseline and 5, 30, 90, 220 min and 48 h after iron administration. Assays for NTBI and transferrin saturation were performed. S. aureus isolates were used to inoculate patient serum samples. Bacterial growth was determined by optical density. RESULTS: Six of 12 patients had NTBI present within 30 min of the iron dose. NTBI was present more frequently in patients with baseline transferrin saturation values >30% (p < 0.05). Bacterial growth was significantly greater in patients who had NTBI present at 5, 90 and 220 min after iron administration compared to those who did not have NTBI present. CONCLUSIONS: Doses of 100 mg of iron sucrose are associated with the presence of NTBI and enhanced S. aureus growth.

Female↗

PubMed2006

Optimizing antimicrobial therapy for gram-positive bloodstream infections in patients on hemodialysis.

Infections with gram-positive organisms are highly prevalent in hemodialysis patients and are a major cause of morbidity and mortality in this population. Antimicrobial therapy is widely used to treat these infections, and prolonged therapy with these agents is often necessary. Extensive use of antimicrobials in hemodialysis patients has resulted in a growing threat of resistance, especially among gram-positive bacteria such as Enterococcus spp and Staphylococcus aureus. Vancomycin-resistant enterococci and S. aureus isolates with reduced susceptibility to vancomycin are increasingly being reported in hemodialysis patients. Additionally, resistance of these organisms to newer agents, such as linezolid and daptomycin, has been documented. Appropriate utilization of antimicrobial therapy to treat these organisms requires an understanding of the pharmacokinetic and pharmacodynamic principles to optimize therapy and avoid adverse drug events. The pharmacokinetic and pharmacodynamic profile of antimicrobial agents can be significantly altered in patients with chronic kidney disease. This review will describe mechanisms of antimicrobial resistance among common gram-positive organisms. The pharmacokinetic and pharmacodynamic principles of cephalosporins, vancomycin, aminoglycosides, linezolid, and daptomycin and applications for use of these agents in the treatment of patients with bloodstream infections on hemodialysis are discussed.

Anti-Bacterial Agents↗

PubMed2004

Vancomycin dosing in high flux hemodialysis: a limited-sampling algorithm.

PURPOSE: The feasibility of using a limited-sampling algorithm for administration of vancomycin for treatment of vascular-access-related bacteremia in outpatient high flux hemodialysis was investigated. METHODS: The original vancomycin-dosing algorithm used at our hemodialysis unit required stat orders for serum vancomycin concentrations before each hemodialysis session to determine the dose of vancomycin to be administered posthemodialysis. Vancomycin concentration data obtained using this original algorithm from January through September 2001 were retrospectively analyzed to determine how many vancomycin concentrations measured 5-20 microg/mL and identify potential clinical predictors of vancomycin removal. RESULTS: A total of 409 serum vancomycin concentrations were drawn during the study period. Ninety-seven percent of concentrations drawn were within 5-20 microg/mL. Twenty-eight patients had data evaluable to determine pharmacokinetic parameters. Mean +/- S.D. vancomycin removal was 39% +/- 13%. Body weight and duration of dialysis alone, blood flow rate, and dialysate flow rate were not predictive of vancomycin removal. Based on these data, a revised algorithm with limited vancomycin sampling data was initiated in December 2002. Retrospective analysis of concentrations obtained and achieved by this algorithm demonstrated a 70% reduction in the number of vancomycin concentration determinations, with 93% of these concentrations within 5-20 microg/mL. The estimated annual cost saving to the hemodialysis unit with the revised algorithm was 7552 dollars. CONCLUSION: A vancomycin-dosing algorithm using limited concentration monitoring for hemodialysis patients achieved comparable vancomycin concentrations to those found with more frequent monitoring and resulted in significant cost savings.

Algorithms↗

PubMedDate not supplied

Sampling for international normalized ratios in patients on hemodialysis with central venous catheters.

The primary objectives of this study were to evaluate the effect of varying heparin concentrations on International Normalized Ratio values and to assess the accuracy of these values deter mined through the arterial line of the dialysis circuit Twenty-two patients on hemodialysis with central venous catheters were studied After a peripheral venipuncture, timed samples from the arterial line of the hemodialysis circuit were obtained after dialysis was initiated and prior to initiating heparin. Assays for coagulation parameters were performed. There was no signifcant difference in any coagulation parameter measured from the arterial line samples compared to the venipuncture samples. Serial heparin dilutions in vitro demonstrated that residual amounts of heparin in the central venous catheter may falsely elevate International Normalized Ratio values. This study demonstrates that accurate International Normalized Ratio values in patients on hemodialysis with heparinized central venous catheters can be obtained ericiently and cost-effectively from the arterial line within 1 minute of dialysis initiation.

Anticoagulants↗