title: Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique.
abstract: Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique.
  
  
  BACKGROUND
  The accuracy with which total body water (TBW) is estimated is a direct determinant of the reliability of Kt/V urea measurements in peritoneal dialysis (PD) patients. Ethanol dilution has been previously shown to be a reliable measure of TBW. Advances in breath alcohol technology make this a feasible clinical tool.
  
  
  METHODS
  We gave 19 fasting chronic PD patients 0.3 g/kg of ethanol (EtOH) orally on two separate occasions. Breath alcohol concentrations (BrACs), determined by dual-beam infrared analysis, were recorded at baseline and periodically thereafter until BrACs were less than 0.01%. The TBW was then determined by standard pharmacokinetic techniques.
  
  
  RESULTS
  TBW measurements were reproducible, with a mean between-run difference of -0.004 liter/kg (95% limits of agreement -0.040 to 0. 032 by Bland-Altman). The Watson equations tended to underestimate TBW, with a mean difference (EtOH - Watson) of +3.0 liters (SD 4.0 liters, P = 0.004) and a mean absolute difference of 4.1 liters (SD 2.7 liters, range -4.4 to 9.5 liters). Kt/V was calculated from dialysate and urine collection, using V as determined from TBW estimates from EtOH and Watson. The mean Kt/V(EtOH) was 2.31 (SD 0. 50) compared with 2.46 (SD 0.52) using Watson. The mean absolute difference between the two Kt/V estimates was 0.26 (SD 0.20, range -0.87 to 0.57), with Kt/V overestimated by Watson in 14 patients. EtOH was well tolerated, and the procedure was completed in about four hours.
  
  
  CONCLUSIONS
  Measuring V by the BrAC technique does not require blood sampling, is reliable, and is reproducible. It is a potentially useful method for a periodic determination of volume that may allow for more accurate Kt/V measurement in PD patients.
authors.affiliation: University of Medicine and Dentistry of New Jersey, Robert Wood JohnsonMedical School, New Brunswick 08903-0019, USA. dahlnv@umdnj.edu
authors.forename: N V
authors.initials: NV
authors.lastname: Dahl
authors.forename: E F
authors.initials: EF
authors.lastname: Foote
authors.forename: T
authors.initials: T
authors.lastname: Kapoian
authors.forename: C A
authors.initials: CA
authors.lastname: Steward
authors.forename: R A
authors.initials: RA
authors.lastname: Sherman
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D001834:Body Water; D001944:Breath Tests / Q000379:methods; D000431:Ethanol; D005260:Female; D006801:Humans; D007201:Indicator Dilution Techniques / Q000592:standards; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000378:metabolism / Q000628:therapy*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000592:standards*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012997:Solvents; D014508:Urea / Q000032:analysis; D014882:Water-Electrolyte Balance
chemical_list: D012997:Solvents; D000431:Ethanol; D014508:Urea