N. Suzuki et al., THE EFFECT OF PLAIN 0.5-PERCENT 2-CHLOROPROCAINE ON VENOUS ENDOTHELIUM AFTER INTRAVENOUS REGIONAL ANESTHESIA IN THE RABBIT, Acta anaesthesiologica Scandinavica, 38(7), 1994, pp. 653-656
The possible venous endothelial toxicity of 0.5% 2-chloroprocaine with
out additives in intravenous regional anaesthesia (IVRA) was evaluated
in rabbits. After exsanguination of a hind limb with an Esmarch's ban
dage a neonatal blood pressure cuff around the thigh was inflated (250
mmHg). For IVRA 4 ml of either plain 0.5% 2-chloroprocaine (pH 3.7),
0.9% NaCl (pH 6.0) or acidified NaCl (pH 3.7) was injected i.v. to the
exsanguinated limb in a randomized, double-blind fashion. Each group
comprised ii rabbits. Eleven rabbits received 4 ml of 0.5 M or 1.0 M K
Cl, for the production of positive controls. Two hours after injection
of the test solution the tourniquet was deflated and venous biopsies
were taken one and 24 hours later for histological and immunocytochemi
cal examination. Five to eight 24-hour samples from each group were al
so processed for electron microscopy. A macroscopic thrombus formation
was observed in four rabbits after KCl and in two after acidified NaC
l administration. No inflammatory changes were observed at. histologic
and immunocytochemical examination of any of the Vein samples. Electr
on microscopy revealed that KCl had caused severe damage to the venous
endothelium of four out of five samples and acidified NaCl had caused
moderate damage to the endothelium of two out of seven samples. 2-chl
oroprocaine had caused moderate damage in four and severe damage in tw
o of the vein samples; two samples were normal. No thrombus formation
occurred. It is concluded that additive-free 2-chloroprocaine caused d
amage to the venous endothelium in rabbits when used for IVRA.