[MICROHEMATOCRIT METHOD].

Despite the clearly established relationship between adequacy of dialysis and response to erythropoietin, recent guidelines on anemia management in end-stage renal disease (ESRD) omit mention of dialysis adequacy while advocating the use of large amounts of intravenous iron. To determine the relative effects of adequacy of dialysis and intravenous iron on hematocrit, we studied 309 hemodialysis patients and analyzed data from 141 hemodialysis facilities in New York State (ESRD Network 2), as well as data from all 18 ESRD Networks in the United States, for the last quarter of 1997. Among the 309 subjects, mean hematocrit differed between quartiles of urea reduction ratio (URR; F statistic = 4; P: = 0.008). Patients with URRs greater than 70% were 2.6 times more likely to have hematocrits greater than 33% (odds ratio, 2.6; 95% confidence interval [CI], 1.3 to 5.3; P: = 0.009) after adjustment for other factors. Mean dialysis facility (n = 141) hematocrits correlated directly with mean URRs (r = 0.32; P: = 0.001). Facilities with a mean URR greater than 70% were three times more likely to have a mean hematocrit greater than 33% (odds ratio, 3; 95% CI, 1.2 to 7.5; P: = 0.02). The percentage of patients in each of the 18 ESRD Networks with hematocrits of 33% or greater correlated inversely with the percentage of patients administered intravenous iron (r = -0.53; P: = 0.03) after adjustment for dose of erythropoietin. We conclude that adequacy of dialysis predicts the response to erythropoietin at both patient and dialysis facility levels. Patients with low hematocrits primarily because of inadequate dialysis may inappropriately be administered excess intravenous iron intended as a corrective measure.

Hematocrit↗

PubMed1999

Optical measurement of hematocrit and other biological constituents in renal therapy.

Optical sensors have advanced significantly over the past 2 decades leading to today's noninvasive optical measurement capabilities and their widespread applications in renal therapy. These measurements provide significant advantages to the clinician. For example, a given blood constituent can be monitored in real time (continuously, nondestructively), which facilitates the ability to optimally "titrate" the therapy with immediate visual feedback. Optical methods have another intrinsic advantage in that each biologic constituent has its own unique spectral "signature" allowing for simultaneous, multiple, and specific measurements of biologic analytes. Use of this budding spectral technology in renal therapy today provides for increased patient safety (by measuring plasma-free hemoglobin, microemboli, clots, oxygen saturation, blood leaks, and hematocrit), measurements of dialysis dose (dialysate urea levels), dry weight (tissue water monitoring), access viability (recirculation, access blood flow), cardiac status (absolute blood volume, cardiac output), and enhanced continuous fluid management (fluid overload, critical blood volume). As microelectronics and signal processing capabilities continue to advance, so will the future of optical diagnosis and treatment. These capabilities translate directly to improved patient quality of life.

Hematocrit↗