INTRADERMAL LIGNOCAINE INJECTIONS INCREASE BLOOD FLUX BUT NOT FLAP SURVIVAL IN RATS

In four groups of six rats a random dorsal flap was raised, and 5, 20, or 200 mg/ml lignocaine or 0.9% sodium chloride, were injected intrad ermally. Cutaneous laser Doppler blood cell flux was measured at 12 ti me points over 130 minutes. In six other groups 5, 20, 100, 200, or 40 0 mg/ml lignocaine concentrations, or sodium chloride were tested. Blo od cell flux was measured at the time that the flap was raised and 30 minutes after the injections. The area of the flap that survived was m easured on day 10. Raising of the flaps resulted in a significant redu ction in blood cell flux, which was followed by a significant increase at 10 minutes (p < 0.05) after the injections with all lignocaine con centrations tested. Injections of 5, 20 and 100 mg/ml lignocaine elici ted a significant increase (p < 0.05) in blood cell flux compared with baseline values. There was no reduction in blood cell flux values at any concentration of lignocaine tested. Compared with sodium chloride, injections of lignocaine had no significant effect on flap survival. We conclude that, despite an increase in blood cell flux, lignocaine h ad no effect on flap survival in this model.