2% Lignocaine Concentration
A 2% lignocaine solution contains 20 mg of lignocaine per milliliter (mL), meaning each 1 mL contains 20 mg of the active drug. 1
Understanding Percentage Concentrations
- The percentage (%) in local anesthetic solutions represents weight/volume (w/v), where 2% means 2 grams per 100 mL of solution 1
- This translates to 2000 mg per 100 mL, which equals 20 mg per 1 mL 1
Practical Clinical Examples from Guidelines
For bronchoscopy procedures: The British Thoracic Society guidelines specify that the maximum safe dose of 8.2 mg/kg for a 70 kg patient equals approximately 29 mL of 2% lignocaine solution, which contains 580 mg total lignocaine 1
For transcricoid injection: A 5 mL injection of 2% lignocaine delivers 100 mg of lignocaine for vocal cord anesthesia 1
For obturator nerve block: Studies document that 10 mL of 2% lignocaine contains 200 mg, while 15 mL contains 300 mg 2
For urethral anesthesia: Research confirms that 20 mL of 2% lignocaine gel delivers 400 mg of lignocaine, while 40 mL delivers 800 mg 3
Common Pitfall to Avoid
- Always calculate total dose in milligrams before administration to avoid exceeding maximum safe doses, particularly in elderly patients or those with hepatic or cardiac impairment where the 8.2 mg/kg limit should be reduced 1