title: Does saline "correct" the abnormal mass balance in metabolic alkalosis associated with chloride depletion in the rat?
abstract: An elevated plasma pH and bicarbonate are the clinical hallmarks of metabolic alkalosis. Nevertheless, to fully define its pathophysiology, one needs a quantitative interpretation of events in 3 areas - the ECF, ICF, and urine. Accordingly, our purpose was to study mass balance in Cl--depletion metabolic alkalosis with normal initial balance for Na+ and K+. In the 20 h following the "exchange" of Cl- (loss, 2455 mumol) and HCO(3-) (gain, 2455 mumol), only 334 mumol HCO(3-) remained in the ECF and 337 mumol were excreted. The remaining 1784 mumol disappeared primarily via titration because 3051 mueq of endogenous anions were produced and excreted largely with K+. Accordingly, metabolic alkalosis was associated with a deficit rather than a surplus of HCO(3-). To reflect the shift of H+ into cells driven by the exit of K+, the cumulative deficit of Cl- was replaced as KCl or NaCl. The fall in plasma [HCO(3-)] was larger in the KCl group (13.2 vs. 9.4 mmol/L); it was largely due to H+ exit from cells; in contrast, disappearance of HCO(3-) from the ECF was due to new endogenous acid production in the NaCl group. Thus, there was an overall deficit of HCO(3-) in metabolic alkalosis associated with KCl depletion (extracellular alkalosis and intracellular acidosis); processes in the ICF were not corrected by NaCl.
authors.affiliation: Renal Division, St. Michael's Hospital, Toronto, Ontario.
authors.forename: A
authors.initials: A
authors.lastname: Scheich
authors.forename: S
authors.initials: S
authors.lastname: Donnelly
authors.forename: S
authors.initials: S
authors.lastname: Cheema-Dhadli
authors.forename: M
authors.initials: M
authors.lastname: Schweigert
authors.forename: S
authors.initials: S
authors.lastname: Vasuvattakul
authors.forename: M L
authors.initials: ML
authors.lastname: Halperin
mesh_terms: D000471:Alkalosis / Q000378:metabolism* / Q000503:physiopathology*; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D002245:Carbon Dioxide / Q000097:blood; D002712:Chlorides / Q000097:blood / Q000378:metabolism* / Q000652:urine; D005110:Extracellular Space / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007424:Intracellular Fluid / Q000378:metabolism; D008297:Male; D010313:Partial Pressure; D011188:Potassium / Q000097:blood / Q000378:metabolism / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000097:blood / Q000378:metabolism / Q000652:urine; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D001639:Bicarbonates; D002712:Chlorides; D002245:Carbon Dioxide; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium