Hemodialysis versus continuous veno-venous hemodiafiltration in the management of severe valproate overdose.

Valproate intoxication is a relatively common clinical problem that can result in coma, respiratory depression, pancytopenia, hemodynamic instability and death [Fernandez et al. 1996, Franssen et al. 1999]. The drug's relatively low molecular weight, small volume of distribution and saturable protein-binding render it potentially amenable to extracorporeal removal (hemofiltration, hemodialysis or hemoperfusion), but published experience is scarce. This report describes a woman with a potentially fatal sodium valproate overdose, who did not respond to continuous veno-venous hemodiafiltration, but was successfully treated with low-flux hemodialysis. Based on our experience, we recommend hemodialysis for serious valproate intoxication.

Peritoneal homocysteine clearance is inefficient in peritoneal dialysis patients.

OBJECTIVES: To investigate the degree and the determinants of peritoneal homocysteine (Hcy) clearance and to compare measured Hcy clearance with the Hcy clearance predicted based on molecular weight (MW). DESIGN: Cross-sectional observational analysis. SETTING: Tertiary care institutional dialysis center. PATIENTS: Sixty-five stable peritoneal dialysis (PD) patients. OUTCOME MEASURES: Fasting blood and 24-hour pooled dialysate effluents were collected for determination of peritoneal clearances of Hcy (CpHcy), urea (CpUr), and creatinine (CpCr). The dialysate-to-plasma creatinine ratio at 4 hours (D/P Cr 4 h) and levels of red cell folate, B12, ferritin, and C-reactive protein (CRP) were measured concurrently. Observed CpHcy was compared with predicted clearance, based on Hcy plasma protein binding and the relative molecular weights of Hcy, urea, and creatinine. RESULTS: Plasma concentrations of Hcy averaged 24.6 +/- 1.1 micromol/L and were elevated above the upper limit of normal in 59 (91%) patients. The mean dialysate concentration of Hcy was 2.9 +/- 0.3 micromol/L, equating to a daily peritoneal elimination of 34.6 +/- 3.6 micromol. Observed CpHcy was closely approximated by predicted CpHcy (8.7 +/- 0.6 L/week/1.73 m2 vs 9.0 +/- 0.3 L/week/1.73 m2 respectively, p = 0.55). Patients maintained on automated PD (n = 5) had a CpHcy similar to that of patients treated with continuous ambulatory peritoneal dialysis (8.9 +/- 1.0 L/week/1.73 m2 vs 8.7 +/- 0.6 L/week/1.73 m2, p = 0.92). The CpHcy was significantly correlated with C-reactive protein (CRP), D/P creatinine, CpUr, CpCr, and peritoneal protein loss, but not with plasma Hcy, albumin, B12, ferritin, age, dialysis duration, peritonitis episodes, or daily dialysate effluent volume. By multivariate analysis, the only variables that remained significant independent predictors of CpHcy were CRP and D/P Cr 4 h. High and high-average transporters had a higher CpHcy than low and low-average transporters (9.7 +/- 0.8 L/week/1.73 m2 vs 7.0 +/- 0.7 L/week/1.73 m2, p < 0.05), despite comparably elevated plasma Hcy concentrations [25.2 +/- 1.5 micromol/L vs 23.4 +/- 1.6 micromol/L, p = nonsignificant (NS)]. CONCLUSIONS: Elevated plasma concentrations of Hcy are not efficiently reduced by PD. The relatively low peritoneal clearance of Hcy is largely accounted for by a high degree of plasma protein binding and is significantly influenced by peritoneal membrane permeability.

Estimations of body composition by various methods.

Body composition was measured in 38 young men all of whom were overweight by standard height-weight tables. The techniques used were body volumetry, determination of total body water by tritium dilution, whole body 40K counting, and anthropometric measurements required for an equation by Wright and Wilmore, the biceps-height formula, and a complex anthropometric model. Body volumeter and total body water dilution results agreed closely. 40K counts gave lower means for the lean mass (higher means for fat mass and percent body fat), while the Wright-Wilmore equation and complex anthropometric model gave high mean values for lean mass (low means for fat mass and percent body fat). Among the five methods correlation coefficients ranged from 0.81 to 0.94 for lean body mass, from 0.74 to 0.89 for fat mass, and from 0.60 to 0.86 for percent body fat. Although all subjects were overweight, only six (16%) were obese.

Body fat: its relationship to coronary heart disease, blood pressure, lipids and other risk factors measured in a large male population.

Obesity is variably considered to be a major contributor to hypertension and hyperlipidemia, and its treatment is recommended in the management of coronary heart disease. Total body fat was measured by tritium dilution in a large male population and its relationship to age, blood pressure, serum lipids, uric acid and the diagnoses of coronary heart disease, hypertension and glucose intolerance was examined. In addition, three commonly used weight: height indices of obesity were correlated with each of these parameters. The correlation of body fat with blood pressure, serum cholesterol and triglycerides, although statistically significant, was of only small magnitude. Mean levels of body fat were not significantly different between patients with coronary disease and control subjects, whereas serum cholesterol and, to a lesser extent, systolic blood pressure were potent risk factors for the disease. It is concluded that obesity is only a minor determinant of blood pressure and lipid level, and that its contribution to coronary heart disease is small or nonexistent.