title: Real time monitoring of propofol blood concentration in ponies anaesthetized with propofol and ketamine.
abstract: This study examined the pharmacokinetics of propofol by infusion in ponies using an analyser for the rapid measurement of propofol concentrations. The analyser (Pelorus 1000; Sphere Medical Ltd., Cambridge, UK) has a measurement cycle of approximately five minutes. Ten Welsh-cross ponies (weighing 135-300 kg) undergoing minor procedures were studied after premedication with acepromazine 0.03 mg/kg and detomidine 0.015 mg/kg. Anaesthesia was induced with ketamine 2 mg/kg and diazepam 0.03 mg/kg, and maintained with an infusion of propofol at an initial rate of 0.16 mg/kg/min for the first thirty minutes, after a bolus of 0.3 mg/kg; and ketamine by infusion (20-40 μg/kg/min). Blood samples (<2 mL) were collected prior to, during and after the infusion, and on assuming standing position. Anaesthesia was uneventful; with the duration of infusion 31-89 min. Blood propofol concentrations during the infusion ranged between 1.52 and 7.65 μg/mL; pseudo-steady state concentrations 3.64-6.78 μg/mL, and concentrations on assuming standing position 0.75-1.40 μg/mL. Propofol clearance and volume of distribution were 31.4 (SD 6.1) mL/min/kg and 220.7 (132.0) mL/kg, respectively. The propofol analyser allows titration of propofol to a given concentration; and may be useful for anaesthesia in animals where kinetics are unknown; in disease states; and where intercurrent therapies affect propofol disposition.
authors: Animal Health Trust, Newmarket, UK. marieke.devries@aht.org.uk
authors: A
authors: A
authors: de Vries
authors: P M
authors: PM
authors: Taylor
authors: G
authors: G
authors: Troughton
authors: B
authors: B
authors: Liu
authors: A L
authors: AL
authors: Fowden
authors: J W
authors: JW
authors: Sear
mesh_terms: D000771:Anesthesia, Intravenous / Q000662:veterinary; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D000818:Animals; D005260:Female; D006736:Horses / Q000097:blood*; D007649:Ketamine / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D008297:Male; D015742:Propofol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology
chemical_list: D018686:Anesthetics, Intravenous; D007649:Ketamine; D015742:Propofol