Potentiation of nerve block in vivo by physiological adjuvants in the solution.
One hundred and seventy-four rats received a standardized 0.4-ml injection into the left infraorbital nerve and all solutions contained lignocaine 0.25 g dl-1. In groups 1-4, the solutions were isoosmotic and contained, besides sodium chloride, potassium chloride 0 or 4 mmol litre-1 and glucose 0 or 20 mmol litre-1 (0 or 360 g dl-1). For groups 5-8, the solutions were hypoosmotic, containing sodium chloride to 0.6 of normal tonicity but were otherwise identical to solutions 1-4. Presence and duration of sensory block were determined from the reflex sublingual electromyographic response to periodic homolateral and contralateral electrical stimulation of the upper lip. In groups 1-4, the presence of potassium chloride 4 mmol litre-1 approximately doubled the duration of blockade (P less than 0.001). Groups 5-8 showed that hypoosmolarity also doubled the duration of block (P less than 0.001), but hypoosmolarity and potassium chloride did not have additive effects. It is concluded that addition of potassium- chloride 4 mmol litre-1 to isotonic solutions of lignocaine is likely to enhance their clinical effectiveness.
D000759:Adjuvants, Anesthesia / Q000494:pharmacology*; D000818:Animals; D004357:Drug Synergism; D004558:Electric Stimulation; D004576:Electromyography; D005947:Glucose / Q000494:pharmacology; D007552:Isotonic Solutions; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009407:Nerve Block; D009994:Osmolar Concentration; D011189:Potassium Chloride / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D000759:Adjuvants, Anesthesia; D007552:Isotonic Solutions; D011189:Potassium Chloride; D008012:Lidocaine; D005947:Glucose