Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique.
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.
Dahl
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University of Medicine and Dentistry of New Jersey, Robert Wood JohnsonMedical School, New Brunswick 08903-0019, USA. dahlnv@umdnj.edu
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Kapoian
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Steward
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Sherman
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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
D012997:Solvents; D000431:Ethanol; D014508:Urea