British Journal of Anaesthesia, 2000, Vol. 85, No. 4 592-598
© 2000 The Board of Management and Trustees of the British Journal of Anaesthesia
Determination of succinylcholine in plasma by high-pressure liquid chromatography with electrochemical detection
Department of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, South Africa
The plasma concentration of the neuromuscular blocking drug, succinylcholine, is difficult to measure. We have measured concentrations of the breakdown product of succinylcholine, choline, to assess whether choline concentration gives an accurate measure of succinylcholine concentration. Choline concentration was measured by HPLC and electrochemical detection in two blood or plasma samples, one in which succinylcholine hydrolysis was inhibited by 105 M physostigmine and another in which succinylcholine was completely hydrolysed in 20 min by 200 mU butyrylcholinesterase at 37°C. The difference in choline content between the two samples gives the succinylcholine concentration. Ninety-five per cent recovery of choline was achieved. Choline standard curves were linear from 156 pmol ml1 to 200 nmol ml1. Within-day and between-day mean coefficients of variation for succinylcholine hydrolysis were small (mean (SD) 3.7% (1.2%) and 3.8% (1.6%), respectively). We conclude that this method of measuring succinylcholine concentration in blood is accurate, repeatable and relatively easy.
Br J Anaesth 2000; 85: 5928