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Effects of Aqueous Chlorhexidine Gluconate Exposure on Thermal, Mechanical and Chromatographic Properties of Polycarbonate and Polyether Urethanes

Tatu, Rigwed R
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1407408200

Abstract Details

2014, MS, University of Cincinnati, Engineering and Applied Science: Materials Science.
Catheter-related bloodstream infections (CRBSI) are one of the major problems faced by patients with renal disease who undergo long-term catheterization for hemodialysis [1]. Polycarbonate and polyether urethanes are most commonly used as long term indwelling catheters in these clinical applications [2].The two routes of CRBSI, namely surgical site infection and contamination of catheter hub are currently prevalent and addressed by cleaning with an antiseptic solution, according to the CDC Guidelines for Prevention of Intravascular Catheter-related infections, 2011 [3].Catheter cleaning methods have evolved over the years with the latest being the use of a disinfectant impregnated sponge to clean the hub prior to initiating hemodialysis [4]. However, this technique does not cater to the proximal caps as well as distal region of the catheter that also needs to be maintained in a sterile condition. Regardless of the methods of sterilization, catheter sites, and time of exposure, the biostability of catheter materials is critical in terms of maintaining the primary role of catheters. In this study, we hypothesize a technique that will expose the catheter hub and distal region to the disinfectant solution for a long time. Owing to the demands for hemodialysis, the polyurethanes used to make the catheter extension need to maintain stability in terms of their mechanical properties and ensure reliable and safe function. The mechanical, thermal and molecular stability of two medical grade polyurethanes commonly used in making catheter extensions for hemodialysis catheters, was investigated. Test conditions involved long term exposure (up to 12 weeks at 37oC and 50% RH) to CHG, a commercially available disinfectant solution (Dyna-Hex 4% aqueous Chlorhexidine Gluconate solution). Post exposure, for Polycarbonate urethane, mechanical tests showed reduction in average strength (from 55.29±0.6 MPa to 48.5±3.98 MPa), average toughness (from 83.27±10.9 J/m3 to 69.9±13.82 J/m3), average modulus (from 25.55±3.53 MPa to 21.88±2.87 MPa) and slight increase in average failure strain (from 288±27% to 290±34%) thermal tests displayed reduction in average Tg (from -3.3±3oC to -8.73±4oC) and crystallization peak attenuation – both these observations were attributed to the plasticization effects of aqueous medium (high percentage of water in CHG solution). Similarly, for Polyether urethane, mechanical tests showed a rise in average strength (from 52.01±4.34 MPa to 64.71±16.93 MPa), average failure strain (from 344±31% to 391±69%), average toughness (from 92.54±10.3 J/m3 to 127.96±42.37 J/m3) and average modulus (from 23.58±6 MPa to 25.3±6.25 MPa) for early time points; thermal tests displayed an appearance of tiny melt endotherms post exposure – both these observations were due to presence of aqueous medium and short range order between hard and soft segments. In terms of molecular stability, both polyurethanes showed no changes in molecular weight and no monomer/oligomer leached out for 12 weeks – which confirms absence of degradation and chain scission. From this study, it can be concluded that polycarbonate and polyether urethanes are good material choices for catheter extensions and safe to be used for a maximum period of 3 months, immersed in 4% aqueous CHG solution to achieve disinfection and reduce the incidence of CRBSI’s.
Balakrishna Haridas, PH.D. (Committee Chair)
Jude Iroh, Ph.D. (Committee Member)
Marepalli Rao, Ph.D. (Committee Member)
Donglu Shi, Ph.D. (Committee Member)
114 p.
Materials Science
catheter; hemodialysis; CRBSI; polyurethanes; biostability; disinfection

Recommended Citations

Citations

  • Tatu, R. R. (2014). Effects of Aqueous Chlorhexidine Gluconate Exposure on Thermal, Mechanical and Chromatographic Properties of Polycarbonate and Polyether Urethanes [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1407408200

    APA Style (7th edition)

  • Tatu, Rigwed. Effects of Aqueous Chlorhexidine Gluconate Exposure on Thermal, Mechanical and Chromatographic Properties of Polycarbonate and Polyether Urethanes. 2014. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1407408200.

    MLA Style (8th edition)

  • Tatu, Rigwed. "Effects of Aqueous Chlorhexidine Gluconate Exposure on Thermal, Mechanical and Chromatographic Properties of Polycarbonate and Polyether Urethanes." Master's thesis, University of Cincinnati, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1407408200

    Chicago Manual of Style (17th edition)

ucin1407408200
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This open access ETD is published by University of Cincinnati and OhioLINK.