title: Interdialytic weight gain and pulmonary membrane diffusing capacity in patients on hemodialysis.
abstract: BACKGROUND
  Measurement of pulmonary diffusion capacity for carbon monoxide (DLCO) may be useful for assessing disease affecting the alveolar-capillary bed or the pulmonary vasculature. It was reported that hemodialysis (HD) therapy causes DLCO reduction via decrease of pulmonary capillary blood volume components. The aim of the study was to evaluate the effect of interdialytic weight gain on pulmonary function and especially DLCO. We further determined whether intravascular volume status, assessed by inferior vena cava diameter (IVCD) contributes to DLCO in patients on HD.
  
  
  METHODS
  Routine pulmonary function testing including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, forced mid-expiratory flow rate (FEF25-75), DLCO IVCD index and other echocardiographic parameters were evaluated in 20 patients (mean age 48.6+/-18.3 years, mean dialysis duration 17.4+/-19.2 months) on chronic HD, 1 hour after HD and after an interdialytic period (1 hour before HD therapy). Single-breath DLCO measurements were corrected for hemoglobin concentration (cDLCO).
  
  
  RESULTS
  Routine pulmonary function tests (spirometry) showed no significant changes in FEV1, FVC and FEF25-75 whereas a statistically significant fall in FEV/FVC was found. At the end of the interdialytic period a statistically significant increase in weight, IVCD index, left ventriculer diastolic diameter (LVDD), and diastolic blood pressure (DBP) were observed (P < 0.05). Using the single-breath DLCO, we found unchanged cDLCO at the end of the interdialytic period. There was no correlation of cDLCO with increases in weight, DBP, IVCD index, LVDD (P > 0.05).
  
  
  CONCLUSIONS
  The accumulation of body water between dialyses has no significant influence on DLCO.
authors.affiliation: Department of Nephrology, Inonu University Faculty of Medicine, Turgut Ozal Medical Center Malatya, Turkey. hulyataskapan.yahoo.com
authors.forename: Hulya
authors.initials: H
authors.lastname: Taskapan
authors.forename: Ramazan
authors.initials: R
authors.lastname: Ulu
authors.forename: Hakan
authors.initials: H
authors.lastname: Gullu
authors.forename: M Cagatay
authors.initials: MC
authors.lastname: Taskapan
authors.forename: Zeki
authors.initials: Z
authors.lastname: Yildirim
authors.forename: Feridun
authors.initials: F
authors.lastname: Kosar
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Sahin
authors.forename: Mine
authors.initials: M
authors.lastname: Kaya
mesh_terms: D006801:Humans; D008875:Middle Aged; D011653:Pulmonary Diffusing Capacity; D012123:Pulmonary Ventilation; D006435:Renal Dialysis; D013997:Time Factors; D015430:Weight Gain