Journal article
On-Line Near-Infrared Spectrometer to Monitor Urea Removal in Real Time during Hemodialysis
Applied spectroscopy, Vol.62(8), pp.866-872
08/2008
DOI: 10.1366/000370208785284411
PMID: 18702859
Abstract
The ex vivo removal of urea during hemodialysis treatments is monitored in real time with a noninvasive near-infrared spectrometer. The spectrometer uses a temperature-controlled acousto optical tunable filter (AOFT) in conjunction with a thermoelectrically cooled extended wavelength InGaAs detector to provide spectra with a 20 cm−1 resolution over the combination region (4000–5000 cm−1) of the near-infrared spectrum. Spectra are signal averaged over 15 seconds to provide root mean square noise levels of 24 micro-absorbance units for 100% lines generated over the 4600–4500 cm−1 spectral range. Combination spectra of the spent dialysate stream are collected in real-time as a portion of this stream passes through a sample holder constructed from a 1.1 mm inner diameter tube of Teflon. Real-time spectra are collected during 17 individual dialysis sessions over a period of 10 days. Reference samples were extracted periodically during each session to generate 87 unique samples with corresponding reference concentrations for urea, glucose, lactate, and creatinine. A series of calibration models are generated for urea by using the partial least squares (PLS) algorithm and each model is optimized in terms of number of factors and spectral range. The best calibration model gives a standard error of prediction (SEP) of 0.30 mM based on a random splitting of spectra generated from all 87 reference samples collected across the 17 dialysis sessions. PLS models were also developed by using spectra collected in early sessions to predict urea concentrations from spectra collected in subsequent sessions. SEP values for these prospective models range from 0.37 mM to 0.52 mM. Although higher than when spectra are pooled from all 17 sessions, these prospective SEP values are acceptable for monitoring the hemodialysis process. Selectivity for urea is demonstrated and the selectivity properties of the PLS calibration models are characterized with a pure component selectivity analysis.
Details
- Title: Subtitle
- On-Line Near-Infrared Spectrometer to Monitor Urea Removal in Real Time during Hemodialysis
- Creators
- David S Cho - Department of Chemistry and Optical Science and Technology Center (D.S.C., J.T.O., M.A.A.), and Department of Internal Medicine, Caver College of Medicine, (M.J.F.), University of Iowa, Iowa City, Iowa 52242Jonathon T Olesberg - Department of Chemistry and Optical Science and Technology Center (D.S.C., J.T.O., M.A.A.), and Department of Internal Medicine, Caver College of Medicine, (M.J.F.), University of Iowa, Iowa City, Iowa 52242Michael J Flanigan - Department of Chemistry and Optical Science and Technology Center (D.S.C., J.T.O., M.A.A.), and Department of Internal Medicine, Caver College of Medicine, (M.J.F.), University of Iowa, Iowa City, Iowa 52242Mark A Arnold - Department of Chemistry and Optical Science and Technology Center (D.S.C., J.T.O., M.A.A.), and Department of Internal Medicine, Caver College of Medicine, (M.J.F.), University of Iowa, Iowa City, Iowa 52242
- Resource Type
- Journal article
- Publication Details
- Applied spectroscopy, Vol.62(8), pp.866-872
- DOI
- 10.1366/000370208785284411
- PMID
- 18702859
- ISSN
- 0003-7028
- eISSN
- 1943-3530
- Language
- English
- Date published
- 08/2008
- Academic Unit
- Physics and Astronomy; Center for Biocatalysis and Bioprocessing; Fraternal Order of Eagles Diabetes Research Center; Chemistry; Internal Medicine
- Record Identifier
- 9984216590402771
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