Effect of anesthetic technique on acute formalin-induced pain in mice.
OBJECTIVE
The aim of this study was to determine if anesthetic technique influences the degree of acute formalin-induced pain in mice.


METHODS
Mice were randomized to receive either combined spinal/general anesthesia or general anesthesia prior to a subcutaneous injection of formalin in a hindpaw. The mice in the combined spinal/general anesthesia group received halothane anesthesia and subarachnoid lidocaine. The mice in the general anesthesia group received halothane anesthesia only. After the mice recovered from anesthesia, paw-licking behavior was recorded for 1 hour. A statistical comparison was made using analysis of variance and the Kolmogorov-Smirnov test.


RESULTS
The mice in the combined spinal/general anesthesia group (n = 20) had a significantly shorter time to first paw lick (mean +/- SD) after formalin injection compared to the mice in the general anesthesia group (n = 20) (16.1 +/- 4.5 vs. 22.1 +/- 6.3 min, P = .002). No difference was observed in the number of paw licks in the mice receiving either combined spinal/general anesthesia or general anesthesia (40 +/- 15 vs. 44 +/- 18, P = .47). No difference was observed in the duration of paw licking in either group (231 +/- 76 vs. 237 +/- 124 s, P = .84).


CONCLUSIONS
The administration of a pre-emptive subarachnoid lidocaine block in the combined spinal/general anesthesia group did not reduce the degree of formalin-induced paw-licking behavior. Combined spinal/general anesthesia did not decrease acute formalin-induced pain in mice.
Fu
E S
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Department of Anesthesiology, University of South Florida College of Medicine, Tampa 33612-4799.
Scharf
J E
JE
D000768:Anesthesia, General / Q000379:methods*; D000775:Anesthesia, Spinal / Q000379:methods*; D000776:Anesthesiology / Q000379:methods; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D005557:Formaldehyde; D051379:Mice; D010146:Pain / Q000139:chemically induced* / Q000517:prevention & control*; D010147:Pain Measurement / Q000187:drug effects
D005557:Formaldehyde