title: Changes in red blood cell size and red cell  fragmentation during hemodialysis.
abstract: BACKGROUND
  Intradialytic hypotension remains the commonest complication for outpatient hemodialysis. The majority of relative blood volume (RBV) monitoring techniques monitor changes in hematocrit. As hematocrit can potentially be affected by changes in red cell size and hemolysis we studied the change in red blood cell size (MCV) during dialysis and hemolysis.
  
  
  METHODS
  MCV was prospectively measured in 176 stable regular adult hemodialysis outpatients (56% male, 27.8% diabetic, mean age 59.5 ±16.2 years) dialyzing against a range of dialysate sodiums (136-145 mmol/L), with cooled dialysate (35-36°C), containing 1 g/L glucose, with constant ultrafiltration profiles. Red cell fragmentation was studied in 41 of the cohort.
  
  
  RESULTS
  Logistical regression analysis showed that the absolute change in MCV was related to the change in hematocrit (F=4.92, β=0.111, p=0.031), and inversely with red cell shrinkage associated with predialysis osmolality (F=5.06, β=0.83, p=0.029), and dialysate sodium (F=4.7, β=0.34, p=0.035). There was no significant increase in red cell fragments during the dialysis sessions.
  
  
  CONCLUSIONS
  Indirect assessment of RBV based upon the relative change in hematocrit, depends not only upon the change in plasma water and red blood cell numbers, but also upon MCV. Changes in MCV may theoretically lead to potential effects on RBV measurements.
authors.affiliation: Center for Nephrology, Royal Free Hospital, London, UK.
authors.forename: John
authors.initials: J
authors.lastname: Booth
authors.forename: Jennifer
authors.initials: J
authors.lastname: Pinney
authors.forename: Andrew
authors.initials: A
authors.lastname: Davenport
mesh_terms: D000328:Adult; D000368:Aged; D000553:Ambulatory Care; D001810:Blood Volume; D048429:Cell Size; D004909:Erythrocyte Indices; D004912:Erythrocytes / Q000473:pathology*; D005260:Female; D006400:Hematocrit; D006461:Hemolysis; D006801:Humans; D007022:Hypotension / Q000097:blood / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control; D016015:Logistic Models; D008131:London; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects*; D018570:Risk Assessment; D012307:Risk Factors