PLASMA LIGNOCAINE CONCENTRATIONS ASSOCIATED WITH EXTRADURAL ANALGESIA IN PATIENTS WITH AND WITHOUT MULTIPLE ORGAN FAILURE

We have measured plasma concentrations of ligno-caine afterthoracic extradural analgesia with continuous infusion of lignocainein eight intensive care patients with chest wall trauma or aftermajor upper abdominal surgery. Four patients developed multipleorgan failure (MOF). Plasma concentrations of lignocaine inarterial blood were measured 4, 8, 24 and 48 h after a continuousinfusion of lignocaine was commenced in the extradural space.Plasma concentrations of lignocaine were greater in all patientswith MOF (range 2.7–5.1 ng ml^–1) than in patientswithout MOF (range 0.8–1.2 fig mh^–1). Because plasmaconcentrations in patients with MOF were within the low toxicrange, extradural infusion of lignocaine should only be consideredin intensive care patients without MOF or when plasma concentrationsof lignocaine are monitored. (Br. J. Anaesth. 1992;69:513–516)