title: Vasopressin secretion by hypertonic saline infusion during hemodialysis: effect of cardiopulmonary recirculation.
abstract: BACKGROUND
  Intradialytic hypotension is the most common and severe acute complication of hemodialysis therapy. In our previous study, infusion of 20 mL of 10% saline into the venous line of a dialyzer increased blood pressure during dialysis hypotension by stimulating arginine vasopressin (AVP) secretion, independent of its effect on plasma volume (PV). This study examines the mechanism by which a small amount of hypertonic solution stimulates AVP secretion.
  
  
  METHODS
  Hemodialysis patients were infused with 20 mL of 2.5 M saline (100 mOsm) over 5 (Protocol 1) or 2 min (Protocol 2) or with isotonic saline (Protocol 3) into the venous line.
  
  
  RESULTS
  Arterial plasma osmolality (Posm) increased by 28.1 and 16.0 (P < 0.0001), while peripheral venous Posm increased by only 8.6 and 8.9 mOsm/kg H(2)O (P < 0.001) in Protocols 2 and 1, respectively. Plasma AVP (P(AVP)) increased significantly by 18.6 and 5.6 pg/mL, PV by 7.2 and 5.5% and mean arterial pressure (MAP) by 15.0 and 7.2 mmHg in Protocols 2 and 1, respectively. Thus, there were large differences in Posm between arterial and peripheral venous blood; osmolar gap, P(AVP) and MAP increased in proportion to the infusion rate. Isotonic saline (30.8 mOsm) infusion increased PV by 8.7% and MAP by 7.2 mmHg.
  
  
  CONCLUSIONS
  Our results indicate that by a mechanism similar to cardiopulmonary recirculation, hypertonic saline infusion caused a striking increase in arterial Posm that enhanced AVP secretion and raised blood pressure. The effect of hypertonic saline on PV was less than one-third of isotonic saline under similar osmolar loads.
authors.affiliation: Department of Internal Medicine, Sumiyoshi Clinic Hospital, Mito, Japan. kurakazu.shimizu@xug.biglobe.ne.jp
authors.forename: Kurakazu
authors.initials: K
authors.lastname: Shimizu
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kurosawa
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Ishikawa
authors.forename: Teizo
authors.initials: T
authors.lastname: Sanjo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001127:Arginine Vasopressin / Q000187:drug effects / Q000378:metabolism*; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007022:Hypotension / Q000188:drug therapy* / Q000209:etiology / Q000517:prevention & control*; D007262:Infusions, Intravenous; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D011446:Prospective Studies; D012016:Reference Values; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D018570:Risk Assessment; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D012462:Saline Solution, Hypertonic; D001127:Arginine Vasopressin