Presented at the American College of Veterinary Internal Medicine Forum, San Antonio, TX, 2008
The Effect of Hetastarch (670/0.75) on Urine Specific Gravity and Osmolality in the Dog
Article first published online: 3 FEB 2009
Copyright © 2009 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 23, Issue 2, pages 388–391, March/April 2009
How to Cite
Smart, L., Hopper, K., Aldrich, J., George, J., Kass, P. and Haskins, S. (2009), The Effect of Hetastarch (670/0.75) on Urine Specific Gravity and Osmolality in the Dog. Journal of Veterinary Internal Medicine, 23: 388–391. doi: 10.1111/j.1939-1676.2008.0252.x
- Issue published online: 3 MAR 2009
- Article first published online: 3 FEB 2009
- Submitted June 15, 2008; Revised August 6, 2008; Accepted November 3, 2008
- Artificial colloid;
- Clinical pathology;
- Fluid therapy
Background: Urine specific gravity (USG) is used clinically to estimate urine osmolality (UOsm). Although USG has been shown to have a linear correlation with UOsm in dogs, the relationship is altered when there are significant numbers of high molecular weight (MW) molecules in the urine.
Hypothesis: USG would no longer predict UOsm in dogs given intravenous hetastarch (670/0.75)(HES).
Animals: Eight healthy employee-owned adult dogs.
Methods: Prospective, controlled experimental study. USG and UOsm were measured every 30 minutes from t=0 minutes to t=360 minutes. Dogs were administered 20mL/kg of either NaCl 0.9% (control group, n=4) or HES (treatment group, n=8) IV over 1 hour starting at t=90 minutes.
Results: There was a decrease in UOsm in both groups starting at t=120 minutes and continuing for the study duration, and there was no significant difference in UOsm between treatment and control groups across all time points. There was an appropriate decrease in USG from t=120 minutes for the control group. In the treatment group, USG increased significantly at t=120 minutes (P= .0006), t=150 minutes (P= .0002), and t=180 minutes (P= .0044). The largest increase in USG occurred at t=150 minutes with a mean USG of 1.070 ± 0.021 (range 1.038-1.104).
Conclusions and clinical importance: Urine specific gravity should not be used to estimate urine solute concentration in dogs following the administration of 20mL/kg of HES. In a clinical setting, the evaluation of USG following this dose of HES may lead to an overestimation of urine concentration.