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Sometime during the reign of Tiberius (25-50 ad) Celsus wrote:A chronic malady may develop in patients who collect water under their skin. The Greeks call this hydrops. There are three species: (1) Sometimes the belly is tense. The Greeks call this tympanites.(2) Sometimes the body is rendered uneven by swellings arising here and there and all over. The Greeks call this hyposarka. (3) Sometimes, the water is all drawn within and is called ascites.

Aim: To evaluate whether factors such as acidosis and hyperphosphataemia that might cause an increased oxygen delivery to tissues could result in increased dosing requirements for intravenous erythropoietin (EPO) administration given to haemodialysis patients. Methods:The clinical records of the patients seen at the Hypertension, Nephrology, Dialysis and Transplantation Clinic from December, 2004 through August, 2005 were reviewed to identify patients who had taken intravenous erythropoietin. Two-tailed, Pearson's correlation was performed to determine correlations between any of the parameters. Analysis of variance and stepwise regression for covariance were used to evaluate the relations of demographic and clinical characteristics and laboratory variables. Analysis of covariance and K means cluster analyses were also performed to examine linkage between variables. Kendall's Tau correlation was used for correlations of non-parametric data. Results: There was a significant direct or positive correlation at the 0.01 levels between dry weight, age, intact parathyroid hormone level (PTH), and serum phosphorus and EPO dose. There was an inverse or negative correlation at that level between the serum bicarbonate and urea reduction ratio (URR) with the EPO dose at the same level while there was a weaker correlation but direct correlation between the white blood count (WBC) and EPO dose. There was significant colinearity between serum phosphorus and PTH but serum phosphorus showed a more significant correlation with EPO overall. Stepwise regression analysis for covariance revealed that phosphorus remained significantly correlated with EPO resistance after the removal of the effect of PTH while PTH lost its significance after the effect of phosphorus was removed. Conclusion: Acidosis and hyperphosphataemia are associated with apparent increased erythropoietin dosing requirements. While this study did not evaluate the mechanism of such requirements and indeed many mechanisms might be possible, a rightward shift in the oxygen-haemoglobin dissociation curve resulting in down-regulation of erythropoietin receptors is considered consistent with the data and present knowledge.

Sevelamer (but not calcium acetate) in addition to calcium carbonate appears to interfere with the bioavailability of levothyroxine.

Background: The fractional excretion of urea (FeUrea) may result in more reliable in the determination of renal function than sodium in the presence of oliguric azotemia; however, its usefulness remains controversial, perhaps due to an evolving understanding of urea transport within the kidney. Methods: This was a prospective observational study of 100 consecutive patients referred to the nephrology service for azotemic oliguria. Multiple clinical variables were analyzed to determine variables responsible for the differences between the FeUrea and fractional excretion of sodium (FeNa) in the ability to distinguish pre-renal azotemia from intrinsic renal disease. Results: Overall, the FeUrea was more accurate (95 vs. 54%, p < 0.0001), yet both tests accurately detected the presence of intrinsic renal disease (FeNa 75%, FeUrea 85%, p = NS). The FeUrea performed significantly better (98 to 49%, p < 0.0001) in detecting pre-renal azotemia, and that advantage came exclusively in patients taking diuretics (p < 0.0001); however, 4/5 cases incorrectly detected by the FeUrea were correctly detected by the FeNa. All 4 cases had infection. Conclusion: The FeUrea appears more accurate in patients receiving diuretics; however, the FeNa may have an advantage in patients with infection.

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Background: Biofilms are dense aggregates of surface adherent microorganisms embedded in a polysaccharide matrix. Intravenous iron and heparin are thought to promote the formation of biofilm. Both are commonly employed during hemodialysis treatments which might affect the incidence of catheter-related sepsis. Methods: 559 patients who underwent hemodialysis treatment with a catheter were reviewed. Episodes of sepsis were analyzed for the use of systemic heparin and intravenous iron as well as all other risk factors for sepsis. Results: Sepsis developed in 141 of the 796 catheters. Analysis of variance revealed that the number of days that the catheter remained in place was the most significant variable (p < 0.0001) associated with catheter-related sepsis along with multiple other variables, but a Cox proportional hazards analysis revealed that only the two biofilm risk factors (intravenous iron [p < 0.001], and mid-treatment bolus of heparin [p = 0.046]) along with previously reported factor of a depressed serum albumin (p = 0.001) are of significance. Conclusion: In addition to duration of catheter use, we found three significant risk factors for sepsis and two of those three have been associated with the development of biofilm.

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