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Lean Body Mass Assessment Based on UV Absorbance in Spent Dialysate and Dual-Energy X-Ray Absorptiometry
摘要： Purpose: The aim of the study was to explore the possibility of assessing lean body mass (LBM) based on UV absorbance measurements in spent dialysate. Methods: 9 patients on chronic three-times-a-week HD (4 female, 5 male, mean age 58.8 ± 8.6 years) were studied. Blood and spent dialysate samples were collected for 3 consecutive hemodialysis (HD) sessions from every patient. A double-beam spectrophotometer was used for the determination of UV absorbance in the collected spent dialysate samples. Dual-energy x-ray absorptiometry (DXA) scans were performed on an interdialytic day. LBM was calculated based on creatinine concentration in blood (LBMblood) and UV absorbance in spent dialysate (LBMa) and assessed by DXA (LBMDXA). Also, in vitro experiments were carried out to investigate the effect of tissue hydration on DXA measurements. Results: Although LBMa was slightly lower compared to LBMblood, the estimates based on UV absorbance in spent dialysate presented greater accuracy and precision compared to LBMDXA. The significant difference between LBMblood and LBMDXA was with high probability caused by the altered tissue hydration of HD patents. Conclusions: In summary, the results show that it is possible to asses LBM based on UV absorbance in spent dialysate.
关键词： Lean body mass,Hemodialysis monitoring,Creatinine,Dual-energy x-ray absorptiometry,UV-absorption
更新于2025-09-23 15:22:29
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Evaluation of choroidal and retinal thickness measurements in adult hemodialysis patients using spectral-domain optical coherence tomography
摘要： Purpose: To assess the effect of hemodialysis on retinal and choroidal thicknesses using spectral-domain optical coherence tomography (SD-OCT). Methods: In this prospective interventional study, 25 hemodialysis patients (17 male, 8 female) were enrolled. All participants underwent high-speed, high-resolution SD-OCT (λ=840 mm; 26.000 A-scans/s; 5 μm resolution) before and after hemodialysis. Choroidal thickness was measured perpendicularly from the outer edge of the retinal pigment epithelium to the choroid-sclera boundary at the fovea and at five additional points: 500 μm and 1000 μm nasal to the fovea and 500 μm, 1000 μm, and 1500 μm temporal to the fovea. Two masked physicians performed the measurements. Choroidal and retinal thicknesses before and after hemodialysis were compared. results: The median choroidal thicknesses before and after hemodialysis were 182 μm (range, 103-374 μm) and 161 μm (range, 90-353 μm), respectively (P<0.001). The median retinal thicknesses were 246 μm (range, 179-296 μm) before and 248 μm (range, 141-299 μm) after hemodialysis (P>0.05). Systolic arterial pressure, diastolic arterial pressure, mean arterial pressure, heart rate, and ocular perfusion pressure significantly decreased after hemodialysis (P<0.001). Intraocular pressure did not vary significantly (P=0.540). conclusion: Hemodialysis seems to cause a significant decrease in choroidal thickness, whereas it has no effect on retinal thickness. This significant decrease in choroidal thickness might be due to the extensive fluid absorption in hemodialysis, which could result in decreased ocular blood flow.
关键词： Choroidal thickness,Hemodialysis,Optical coherence tomography
更新于2025-09-23 15:22:29
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Changes in cerebral oxygenation and cerebral blood flow during hemodialysis – A simultaneous near-infrared spectroscopy and positron emission tomography study
摘要： Near-infrared spectroscopy (NIRS) is used to monitor cerebral tissue oxygenation (rSO2) depending on cerebral blood flow (CBF), cerebral blood volume and blood oxygen content. We explored whether NIRS might be a more easy applicable proxy to [15O]H2O positron emission tomography (PET) for detecting CBF changes during hemodialysis. Furthermore, we compared potential determinants of rSO2 and CBF. In 12 patients aged (cid:2) 65 years, NIRS and PET were performed simultaneously: before (T1), early after start (T2), and at the end of hemodialysis (T3). Between T1 and T3, the relative change in frontal rSO2 (DrSO2) was (cid:3)8 (cid:4) 9% (P ? 0.001) and (cid:3)5 (cid:4) 11% (P ? 0.08), whereas the relative change in frontal gray matter CBF (DCBF) was (cid:3)11 (cid:4) 18% (P ? 0.009) and (cid:3)12 (cid:4) 16% (P ? 0.007) for the left and right hemisphere, respectively. DrSO2 and DCBF were weakly correlated for the left (r 0.31, P ? 0.4), and moderately correlated for the right (r 0.69, P ? 0.03) hemisphere. The Bland-Altman plot suggested underestimation of DCBF by NIRS. Divergent associations of pH, pCO2 and arterial oxygen content with rSO2 were found compared to corres- ponding associations with CBF. In conclusion, NIRS could be a proxy to PET to detect intradialytic CBF changes, although NIRS and PET capture different physiological parameters of the brain.
关键词： cerebral oximetry,hemodialysis,water-PET,Brain perfusion,NIRS
更新于2025-09-04 15:30:14