Real time monitoring of propofol blood concentration in ponies anaesthetized with propofol and ketamine.

The research study in this article observes the pharmacokinetics of propofol in ponies when combined with ketamine during anaesthesia, using an analyser tool for quick propofol concentration measurements.

Research Context and Objectives

• The study focuses on the investigation of the absorption, distribution, metabolism, and elimination of propofol, a commonly used anesthetic. The research is performed on Welsh-cross ponies undergoing minor procedures. The objective of this investigation is to assess real-time propofol concentration in the ponies’ blood during anaesthesia using the Pelorus 1000 analyser.

Methodology

• Ten Welsh-cross ponies were premedicated with acepromazine and detomidine before being anaesthetized with a combination of ketamine, diazepam, and propofol. The initial dose of propofol was delivered at a rate of 0.16 mg/kg/min for the first thirty minutes post a bolus infusion of 0.3 mg/kg, with an additional infusion of ketamine.
• Less than 2 ml of blood samples were collected prior to the procedure, during the infusion process, after the procedure, and after the pony regained its standing position. The duration of the infusion lasted anywhere from 31 to 89 minutes.

Results

• The recorded blood propofol concentrations during the infusion process ranged between 1.52 and 7.65 μg/mL, with pseudo steady state concentrations falling between 3.64 and 6.78 μg/mL. The concentrations upon the pony standing up again ranged from 0.75 to 1.40 μg/mL.
• The propofol clearance and volume distribution measured 31.4 (SD 6.1) mL/min/kg and 220.7 (132.0) mL/kg respectively, providing data on how the ponies’ bodies processed and distributed the drug.

Conclusion

• The propofol analyser used proved effective for measuring propofol concentrations in real-time, enabling dosage titration to a specific concentration during the anaesthesia process.
• This tool may be useful for scenarios where drug kinetics are unknown, in various disease states, or where other therapies used concurrently may affect propofol disposition.