PLASMAPHERESIS AND PLASMA CHOLINESTERASE

Plasma cholinesterase (E.C. 3.1.1.8[EC]) concentrations were measuredin nine outpatients who were undergoing regular plasmapheresis.A single plasmapheresis produced a 64% reduction in cholinesteraseconcentration compared with the value before plasmapheresis.Another patient who received four plasma exchanges in 6 daysshowed a progressive reduction in cholinesterase concentrationto only 8% of the initial value. It is suggested that drugsmetabolized by cholinesterase should be used with caution inpatients undergoing plasmapheresis, particularly when frequentpalsma exchanges are undertaken. ^*Present address: Department of Anaesthetics, Northwick ParkHospital, Watford Road, Harrow, Middlesex HA1 3UJ.