title: Effects of propofol and of thiopentone anaesthesia on the renal clearance of cefoxitin in the sheep.
abstract: We have examined the renal extraction ratios and clearances of cefoxitin in three groups of adult merino ewes. One group (n = 3) was studied for 12 h without perturbation; these were designated control studies. The other two groups (n = 4 each) were studied before (baseline values), during and after the induction and 70-min maintenance of anaesthesia with propofol or thiopentone. In the control studies, mean renal extraction ratio and clearance for cefoxitin were, respectively, 0.67-0.92 and 0.66-0.91 litre min-1 and were consistent throughout the entire study period in individual animals. Comparable values were obtained as baseline values in the anaesthesia groups. Compared with individual baseline values, blood concentrations of cefoxitin doubled during anaesthesia with each agent. At the same time, renal extraction ratio and clearance for cefoxitin each decreased significantly to about 50-60% of their control values. Recovery to control values of arterial blood concentrations and renal extraction ratio of cefoxitin took at least 5 h, but recovery of renal clearance was more rapid. The results indicate that renal elimination of an organic anion such as cefoxitin may be affected by changes in renal blood flow and in renal function produced by propofol and thiopentone; these effects may last for several hours after recovery of renal blood flow.
authors.affiliation: Department of Anaesthesia and Intensive Care, Flinders University of South Australia, Adelaide.
authors.forename: D G
authors.initials: DG
authors.lastname: Selby
authors.forename: L E
authors.initials: LE
authors.lastname: Mather
authors.forename: W B
authors.initials: WB
authors.lastname: Runciman
mesh_terms: D000771:Anesthesia, Intravenous; D000818:Animals; D002440:Cefoxitin / Q000097:blood*; D005260:Female; D007668:Kidney / Q000502:physiology*; D008137:Longitudinal Studies; D015742:Propofol; D012079:Renal Circulation; D012756:Sheep; D013874:Thiopental; D013997:Time Factors
chemical_list: D002440:Cefoxitin; D013874:Thiopental; D015742:Propofol