title: The effect of furosemide on intravascular volume status and electrolytes in patients receiving mannitol:  an intraoperative safety analysis.
abstract: BACKGROUND
  Mannitol is often used during intracranial surgery to improve surgical exposure. Furosemide is often added to mannitol to augment this effect. The concern exists, however, that the augmented diuresis caused by the addition of furosemide to mannitol may cause hypovolemia and hypoperfusion, hypokalemia, and hyponatremia. We examined the intraoperative safety of low-dose furosemide (0.3 mg/kg) combined with mannitol (1 g/kg).
  
  
  METHODS
  We observed 23 patients in a double-blind, block randomized, placebo-controlled study to examine the effects of furosemide (0.3 mg/kg) when combined with mannitol (1 g/kg) on surgical brain relaxation for tumor surgery. Mannitol and the study drug (furosemide or placebo) were administered, and arterial blood gases with electrolytes (sodium, potassium, and lactic acid) and urine output volume were recorded every 30 minutes for 3 hours. Plasma sodium, potassium, and lactic acid concentrations, and interval urine outputs, were compared across time and between furosemide-placebo assignment groupings, with a P<0.01 considered significant.
  
  
  RESULTS
  Although mannitol produced a large volume of diuresis (1533±335 mL), the addition of a low dose of furosemide substantially increased both the rate of production of urine for the first 90 minutes after administration and the total volume of urine produced (2561±611 mL, P<0.001, compared with placebo group). The addition of furosemide did not produce a serum potassium level below 3.8±0.7 mEq/L, a serum sodium level below 128.3±3.4 mEq/L, or a serum lactic acid level above 2.4±0.9 mmol/L. There were no differences in the plasma potassium concentration, sodium concentration, or lactic acid concentration between the drug groups at any time point.
  
  
  CONCLUSIONS
  Despite an increase in urine output by as much as 67%, adding low-dose furosemide to mannitol does not seem to produce significant electrolyte derangements or hypovolemia compared with the administration of mannitol alone.
authors.affiliation: Department of Anesthesiology & Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: Bebawy
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Ramaiah
authors.forename: Carine
authors.initials: C
authors.lastname: Zeeni
authors.forename: Laura B
authors.initials: LB
authors.lastname: Hemmer
authors.forename: Antoun
authors.initials: A
authors.lastname: Koht
authors.forename: Dhanesh K
authors.initials: DK
authors.lastname: Gupta
mesh_terms: D000328:Adult; D000368:Aged; D062186:Arterial Pressure / Q000187:drug effects; D001810:Blood Volume / Q000187:drug effects*; D001932:Brain Neoplasms / Q000601:surgery; D000077324:Crystalloid Solutions; D004232:Diuretics / Q000009:adverse effects / Q000494:pharmacology*; D004311:Double-Blind Method; D004573:Electrolytes / Q000097:blood*; D005260:Female; D005665:Furosemide / Q000009:adverse effects / Q000494:pharmacology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007430:Intraoperative Care; D007552:Isotonic Solutions / Q000627:therapeutic use; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008353:Mannitol / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D061214:Patient Safety; D010952:Plasma Substitutes / Q000627:therapeutic use; D014563:Urodynamics / Q000187:drug effects
chemical_list: D000077324:Crystalloid Solutions; D004232:Diuretics; D004573:Electrolytes; D007552:Isotonic Solutions; D010952:Plasma Substitutes; D019344:Lactic Acid; D008353:Mannitol; D005665:Furosemide