LIDOCAINE INHIBITS BLOOD-COAGULATION - IMPLICATIONS FOR EPIDURAL BLOOD PATCH

Lidocaine in the epidural space, through inhibitory effects upon coagu lation, may contribute to inefficacy of epidural autologous blood patc h (EBP). This study was undertaken to evaluate the effect of achievabl e epidural concentrations of lidocaine on blood coagulation as a step in testing this hypothesis. Ex vivo blood coagulation using whole bloo d (n = 20) was studied with computerized thrombelastography (TEG). Eac h blood specimen was exposed to serial dilutions of lidocaine hydrochl oride or saline to form end-concentrations of 0.0 mM, 2.3 mM, 4.6 mM, 9.2 mM, 18.5 mM, and 36.9 mM lidocaine. Statistical analysis using ana lysis of variance for repeated measures revealed that the three highes t lidocaine concentrations tested caused hypocoagulable and/or fibrino lytic changes as compared with controls. Achievable epidural admixture s of lidocaine and whole blood will impair coagulation. Therefore, res idual lidocaine in the epidural space may contribute to failures of im mediate or early EBP.