Lidocaine and bupivacaine exert differential effects on whole blood coagulation.
OBJECTIVE
To compare bupivacaine to lidocaine's effects on blood clotting at two concentrations, and to characterize and determine relative effects of two equianalgesic bupivacaine and lidocaine concentrations.


METHODS
Prospective, dual-controlled, whole blood equal volume admixture thrombelastographic (TEG) study.


METHODS
University of Pennsylvania Medical Center operating rooms.


METHODS
20 ASA physical status I and II patients' blood comprised control groups and anesthetic groups.


METHODS
Analysis of whole blood clotting used six TEG channels for untreated and saline controls and four final concentrations (1.0% lidocaine, 0.5% lidocaine, 0.25% bupivacaine, and 0.125% bupivacaine) of local anesthetics. Saline control and the local anesthetic-treated specimens underwent 8.3% hemodilution.


RESULTS
Blood was studied. Saline control or four anesthetic solutions (30 microliters) were added in random order two 5 TEG cuvettes. Whole blood (330 microliters) was mixed ex vivo at 37 degrees C. A sixth channel with untreated whole blood (360 microliters) acted as an undiluted control. Data for four TEG parameters [reaction time (r), angle (alpha), maximum amplitude (MA), and percent decrease in TEG amplitude from MA 30 minutes after MA acquisition (Lysis 30)] for undiluted control and saline volumetric controls were compared to each other using Student's t-test for paired observations. Lidocaine and bupivacaine groups' TEGs were compared to the paired saline control analysis of variance for repeated measures. A p-value less than 0.05 was considered significant. There was no difference between whole blood and saline control TEGs. All local anesthetics produced significant hypocoagulable changes from control. Angle alpha and MA were significantly decreased in all local anesthetic groups. Ther time was prolonged only in the high lidocaine-treated blood. Lysis was a feature of the low lidocaine and bupivacaine solutions. Equianalgesic lidocaine produced more profound hypocoagulable effects than did bupivacaine.


CONCLUSIONS
Lidocaine and bupivacaine both significantly impaired TEG coagulation in a concentration-dependent manner. Lidocaine was significantly more hypocoagulable than bupivacaine at two similarly analgesic concentrations.
Department of Anesthesia, Hospital of the University of Pennsylvania, Philadelphia 19104, USA.
M D
MD
Tobias
C
C
Henry
Y G
YG
Augostides
D000704:Analysis of Variance; D000779:Anesthetics, Local; D001777:Blood Coagulation / Q000187:drug effects*; D002045:Bupivacaine; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008012:Lidocaine; D013916:Thrombelastography
D000779:Anesthetics, Local; D008012:Lidocaine; D002045:Bupivacaine