[The Bier block as an experimental tool to differentiate peripheral and central effects of analgesics on people].
OBJECTIVE
In this study the technique of intravenous regional anesthesia (Bier block) was evaluated as an experimental tool to differentiate peripheral and central effects of analgesics.


METHODS
Touch and pain thresholds were assessed under control conditions and during a prolonged Bier block. In addition, models of experimental pain and hyperalgesia were used (Capsaicin injection, histamine iontophoresis, pinch).


RESULTS
No signs of impaired function of Adelta- und C-fibers were found during a Bier block of up to 30 min after onset of ischemia. In contrast, Abeta-mediated touch sensation declined significantly. On the basis of these results, peripheral mechanisms of action could be verified for low-dose lidocaine and for morphine in the Bier block setting.


CONCLUSIONS
The Bier-block setting can be successfully employed to differentiate peripheral and central modes of action of analgesics.
Koppert
W
W
Klinik für Anästhesiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg. koppert@physiologie1.uni-erlangen.de
Sittl
R
R
Schmelz
M
M