Comparison of lactated Ringer's solution and a physiologically balanced 6% hetastarch plasma expander for the treatment of hypotension induced via blood withdrawal in isoflurane-anesthetized dogs.
OBJECTIVE
To compare the effects of lactated Ringer's solution (LRS) with those of a physiologically balanced 6% hetastarch plasma expander administered to isoflurane-anesthetized dogs with hypotension induced by blood withdrawal.


METHODS
12 healthy Beagles.


METHODS
Blood was withdrawn from isoflurane-anesthetized dogs (volume withdrawn measured) to a systolic arterial blood pressure (SAP) of 80 mm Hg. Six dogs each received either LRS or hetastarch solution (90 mL/kg/h, i.v.). Hemodynamic variables, pH, blood gas concentrations, PCV, serum electrolyte and total protein concentrations, and colloid osmotic pressure (COP) were determined at baseline, while SAP was 80 mm Hg, and after fluid treatment. The volume of fluid administered and rate of return of SAP to within 10% of baseline values were recorded.


RESULTS
Mean +/- SD volume of blood withdrawn to decrease SAP to 80 mm Hg was 173 +/- 38 mL. Hemodynamic variables decreased after blood withdrawal but returned to baseline values more rapidly after infusion of a smaller volume of hetastarch solution, compared with the response to LRS infusion. Whereas PCV and serum total protein concentration decreased after administration of either solution, COP decreased only after administration of LRS. The total volume of hetastarch solution and LRS required to restore and maintain SAP to within 10% of baseline values was 1.1 +/- 0.9 and 4.4 +/- 1.7 times greater than the volume of blood removed, respectively.


CONCLUSIONS
Compared with LRS infusion, smaller volumes of hetastarch solution normalized and maintained SAP without lowering COP in isoflurane-anesthetized dogs after blood withdrawal.
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
William W
WW
Muir
Ashley J
AJ
Wiese
D000704:Analysis of Variance; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure; D001798:Blood Proteins; D001810:Blood Volume / Q000662:veterinary; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004573:Electrolytes / Q000097:blood; D006439:Hemodynamics; D006863:Hydrogen-Ion Concentration; D006895:Hydroxyethyl Starch Derivatives / Q000627:therapeutic use*; D007022:Hypotension / Q000188:drug therapy / Q000662:veterinary*; D007530:Isoflurane; D007552:Isotonic Solutions / Q000627:therapeutic use*; D009997:Osmotic Pressure / Q000187:drug effects; D000077325:Ringer's Lactate; D013997:Time Factors
D001798:Blood Proteins; D004573:Electrolytes; D006895:Hydroxyethyl Starch Derivatives; D007552:Isotonic Solutions; D000077325:Ringer's Lactate; D007530:Isoflurane