title: Fluid volume kinetics of dilutional hyponatremia; a shock syndrome revisited.
abstract: OBJECTIVE
  To evaluate whether the pathophysiology of shock syndromes can be better understood by comparing central hemodynamics with kinetic data on fluid and electrolyte shifts.
  
  
  METHODS
  We studied the dilutional hyponatremic shock that developed in response to overhydration with electrolyte-free irrigating fluid - the so-called 'transurethral resection syndrome' - by comparing cardiac output, arterial pressures, and volume kinetic parameters in 17 pigs that were administered 150 ml/kg of either 1.5% glycine or 5% mannitol by intravenous infusion over 90 minutes.
  
  
  RESULTS
  Natriuresis appeared to be the key factor promoting hypovolemic hypotension 15-20 minutes after fluid administration ended. Excessive sodium excretion, due to osmotic diuresis caused by the irrigant solutes, was associated with high estimates of the elimination rate constant (k10) and low or negative estimates of the rate constant describing re-distribution of fluid to the plasma after translocation to the interstitium (k21). These characteristics indicated a high urinary flow rate and the development of peripheral edema at the expense of plasma volume and were correlated with reductions in cardiac output. The same general effects of natriuresis were observed for both irrigating solutions, although the volume of infused 1.5% glycine had a higher tendency to enter the intracellular fluid space.
  
  
  CONCLUSIONS
  Comparisons between hemodynamics and fluid turnover showed a likely sequence of events that led to hypovolemia despite intravenous administration of large amounts of fluid.
authors: Södertälje Hospital, Research Unit, Södertälje, Sweden, Södertälje Hospital, Research Unit, Södertälje, Sweden.
authors: Robert G
authors: RG
authors: Hahn
authors: Chalmers University of Technology, Gothenburg, Sweden, Chalmers University of Technology, Gothenburg, Sweden.
authors: Tobias
authors: T
authors: Gebäck
mesh_terms: D000818:Animals; D002302:Cardiac Output / Q000187:drug effects; D004234:Diuretics, Osmotic / Q000008:administration & dosage; D004573:Electrolytes; D005998:Glycine / Q000008:administration & dosage; D018684:Glycine Agents / Q000008:administration & dosage; D006439:Hemodynamics / Q000502:physiology*; D007010:Hyponatremia / Q000209:etiology / Q000503:physiopathology*; D007022:Hypotension / Q000209:etiology / Q000503:physiopathology*; D020896:Hypovolemia / Q000209:etiology / Q000503:physiopathology; D007262:Infusions, Intravenous; D007700:Kinetics; D008353:Mannitol / Q000008:administration & dosage; D011183:Postoperative Complications / Q000503:physiopathology; D013552:Swine; D013577:Syndrome; D007507:Therapeutic Irrigation / Q000009:adverse effects*; D013997:Time Factors; D020728:Transurethral Resection of Prostate / Q000009:adverse effects*
chemical_list: D004234:Diuretics, Osmotic; D004573:Electrolytes; D018684:Glycine Agents; D008353:Mannitol; D005998:Glycine