Changes in colloid osmotic pressure as a function of anesthesia and surgery in the presence and absence of isotonic fluid administration in dogs.
OBJECTIVE
To determine how a combination of anesthetic drugs; including pre-medication, induction agents and inhalational agents; affect colloid osmotic pressure (COP) in the presence and absence of isotonic fluid administration. Secondarily, to determine if changes in total plasma protein (TPP) correlate with COP in anesthetized patients.


METHODS
Prospective, randomized clinical study.


METHODS
Ten female dogs, 4 months to 4 years of age and >8 kg undergoing elective ovariohysterectomy.


METHODS
All dogs were anesthetized in a similar fashion. After induction, five dogs received lactated ringer's solution (LRS) at 10 mL kg(-1) hour(-1) and five dogs received no fluid therapy during anesthesia. Blood samples were collected prior to pre-medication, prior to induction, immediately post-induction/prior to the inhalational agent, 30 minutes post-induction, at the time of recovery and 45 minutes post-discontinuation of inhalant. TPP and COP were measured from each sample.


RESULTS
Administration of fluids resulted in a decrease in COP and TPP over time that did not return to baseline by 45 minutes after recovery. Anesthesia without the administration of fluids also resulted in a significant decrease in COP over time, that was rebounding by recovery (but still significantly less than baseline). TPP had variable correlation with COP at different time points with or without fluid administration.


CONCLUSIONS
Anesthetic drugs alter COP similarly in the presence and absence of isotonic fluids. These changes in COP did not have a simple relationship to TPP and so the latter could not be used to predict COP in this patient population.
Wright
Bonnie D
BD
College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Veterinary Medical Center, 300 West Drake Boulevard, Fort Collins, CO 80523, USA. wrightb@lamar.colostate.edu
Hopkins
Amber
A
D019162:Anesthetics, Combined / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001798:Blood Proteins / Q000032:analysis* / Q000378:metabolism; D003102:Colloids / Q000378:metabolism; D004285:Dogs / Q000097:blood / Q000502:physiology* / Q000601:surgery; D005260:Female; D005440:Fluid Therapy / Q000662:veterinary; D007044:Hysterectomy / Q000662:veterinary; D007552:Isotonic Solutions / Q000008:administration & dosage*; D009997:Osmotic Pressure / Q000187:drug effects* / Q000502:physiology; D010052:Ovariectomy / Q000662:veterinary; D011446:Prospective Studies; D000077325:Ringer's Lactate
D019162:Anesthetics, Combined; D001798:Blood Proteins; D003102:Colloids; D007552:Isotonic Solutions; D000077325:Ringer's Lactate