The Critical Role of Concentration for Lidocaine Block of Peripheral Nerve In Vivo 

Abstract

Blocks of greater depth and longer duration result from injection of smaller volumes and, correspondingly, higher lidocaine concentrations containing the same dose. The corollary is that lower lidocaine doses are required to achieve the same effect when smaller volumes are injected. Curiously, when the equivalent E50 is injected, total drug taken into the nerve is less from the smaller volumes than from the larger volumes, even though the peak functional effects are equal. Total intraneural local anesthetic may not represent the effective drug in the compartment that contains nerve axons, the actual location of neural blockade.

Increased Sensitivity to Thermal Pain and Reduced Subcutaneous Lidocaine Efficacy in Redheads

“…However, without a dose-response relationship, it remains unclear whether this represents absolute failure of local anesthetic action or merely a shift of the dose response curve to the right. 30 In other words, redheads may simply require more local anesthetic, but ultimately obtain adequate analgesia.…”

The vanilloid receptor TRPV1 is activated and sensitized by local anesthetics in rodent sensory neurons

“…The clinical use for spinal anesthesia and peripheral regional anesthesia requires the administration of highly concentrated LAs in order to achieve rapid and sufficient pain suppression (3,4). Clinically used formulations of 1%-5% lidocaine correspond to about 40-200 mM lidocaine.…”

Determination of trigeminocardiac reflex during rhinoplasty

“…18 The role of LAC volume on nerve block was not studied in the present study. Further studies are needed to determine the correlation between TCR and the dose of LAC.…”