Plasma volume, albumin, and fluid status in peritoneal dialysis patients.
OBJECTIVE
Peritoneal dialysis (PD) patients may be overhydrated especially when inflammation is present. We hypothesized that patients with a plasma albumin below the median value would have measurable overhydration without a proportional increase in plasma volume (PV).


METHODS
We investigated a cross-sectional sample of 46 prevalent PD patients powered to detect a proportional increase in PV associated with whole body overhydration and hypoalbuminemia. PV was determined from (125)I-labeled albumin dilution, absolute total body water from D dilution (TBW(D)), and relative hydration from multifrequency bioimpedance analysis (BIA; Xitron 4200) expressed as the extracellular water (ECW):TBW(BIA) ratio.


RESULTS
Whereas patients with plasma albumin below the median (31.4 g/dl) were overhydrated as determined both by BIA alone (ECW:TBW(BIA) 0.49 versus 0.47, P < 0.036) and the difference between estimated TBW(BIA) and measured TBW(D) (3.55 versus 0.94 L, P = 0.012), corrected PV was not different (1463 versus 1482 ml/m(2), NS). Mean PV was not different from predicted, and its variance did not correlate with any other clinical measures. Multivariate analysis showed that the only independent predictor of whole body overhydration was reduced plasma albumin.


CONCLUSIONS
Hypoalbuminemia is an important determinant of tissue overhydration in PD patients. This overhydration is not associated with an increased plasma volume. Attempts to normalize the ECW:TBW ratio in hypoalbuminemic, inflamed PD patients may lead to hypovolemia and loss of residual renal function.
Department of Nephrology, University Hospital of North Staffordshire, Stoke on Trent, Staffordshire, United Kingdom.
Biju
B
John
B Kay
BK
Tan
Stephen
S
Dainty
Patrik
P
Spanel
David
D
Smith
Simon J
SJ
Davies
D000328:Adult; D000368:Aged; D001823:Body Composition; D001834:Body Water / Q000378:metabolism; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D004739:England; D005260:Female; D006801:Humans; D034141:Hypoalbuminemia / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D020896:Hypovolemia / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000009:adverse effects; D010953:Plasma Volume; D011865:Radioisotope Dilution Technique; D012709:Serum Albumin / Q000378:metabolism*; D014882:Water-Electrolyte Balance; D014883:Water-Electrolyte Imbalance / Q000097:blood / Q000209:etiology* / Q000503:physiopathology
D012709:Serum Albumin