title: Assessment of total body water in hemodialysis patients by a single oral dose of antipyrine.
abstract: Accurate determination of total body water in hemodialysis patients is important for calculation of the amount of fluid excess that should be removed by ultrafiltration, and for dialysis prescribing by KT/V. Indirect methods using 0.6 x body weight or pre and post serum urea concentrations are inaccurate and determination by tritiated water space requires the use of radioactivity. The authors measured the volume of distribution for antipyrine that is distributed in body water, and compared it to tritiated water space in hemodialysis patients. Sixteen patients on hemodialysis were given 500 mg antipyrine and saliva samples were collected at fixed time points. Concentrations of antipyrine in saliva were measured by high pressure liquid chromatography. Volume of distribution for antipyrine was calculated by pharmacokinetic methods. Fluid excess was determined as the difference between tritiated water space or volume of distribution for antipyrine and ideal total body water measured anthropometrically. Total body water as the volume of distribution for antipyrine was 24.8 to 61.5 (mean 44.0 +/- 10.3) L, or 68% of body weight, and tritiated water space 27.0 to 56.6 L (43.6 +/- 7.7), 67% of body weight. Volume of distribution for antipyrine correlated well with tritiated water space (r = 0.997 and p = 0.001). Fluid excess calculated from tritiated water space was between 2.5 and 12.4 (6.0 +/- 4.0) L, and from volume of distribution for antipyrine -0.7 to 13.3 (5.7 +/- 5.1) L (r = 0.80, p = 0.001). The authors conclude that by using a single oral dose of antipyrine, one can simply and accurately measures total body water in hemodialysis patients.
authors.affiliation: Department of Internal Medicine, Karolinska Hospital, Stockholm, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Odar-Cederlöf
authors.forename: C G
authors.initials: CG
authors.lastname: Eriksson
authors.forename: F
authors.initials: F
authors.lastname: Albertioni
authors.forename: F
authors.initials: F
authors.lastname: Ericsson
authors.forename: C M
authors.initials: CM
authors.lastname: Kjellstrand
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000983:Antipyrine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001834:Body Water / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D006435:Renal Dialysis; D012463:Saliva / Q000737:chemistry; D014316:Tritium
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D014316:Tritium; D000983:Antipyrine