The Effect of Anesthetic Techniques on Blood Coagulability in Parturients as Measured by Thromboelastography

Anesthetic techniques may affect blood coagulability and the subsequent incidence of thromboembolic events.The purpose of this study was to evaluate the effect of spinal and general anesthesia on blood coagulability in normal pregnant women undergoing cesarean section, using thromboelastography. In the spinal anesthesia group (n = 15), thromboelastography was performed after crystalloid preloading and during the immediate postanesthesia course. In the general anesthesia group (n = 15), thromboelastography was performed before induction and during the immediate postanesthesia course. Values for all thromboelastographic variables (reaction time [r], clot formation time [K], coagulation time [rK], maximum amplitude [MA], elastic shear modulus [G], clot formation rate [alpha angle], and coagulation index [CI]) in the preanesthesia period were similar in both the spinal and general anesthesia groups. However, in the postanesthesia period, r and K significantly decreased (P < 0.05), and alpha angle (P < 0.05) and CI significantly increased (P < 0.01) in the general anesthesia group when compared with the spinal anesthesia group. In the postanesthesia period, MA and G were similar in both groups. In the spinal anesthesia group, thromboelastographic variables did not change significantly in the postanesthesia compared with the preanesthesia period. We conclude that the use of general anesthesia for cesarean section is associated with accelerated coagulability when compared with spinal anesthesia. (Anesth Analg 1997;85:82-6)