Evaluation of the safety of inguinal hernia repair in the elderly using lignocaine infiltration anaesthesia.

Repair of inguinal hernia using local anaesthesia is becoming increasingly popular as it avoids many of the systemic side effects associated with general or spinal/epidural anaesthesia and provides excellent early postoperative pain relief. Dosages of local anaesthetic approaching the recommended maximum are frequently required for adequate anaesthesia of the inguinal region. The present study describes the disposition and safety of lignocaine with adrenaline in 14 elderly patients to ascertain its safety with a view to more widespread application of the technique in more complicated hernia repairs. Serial plasma lignocaine concentrations were determined for up to 24 h following doses approaching the recommended maximum for infiltration (7 mg/kg). Peak lignocaine concentrations (normalized to 7 mg/kg) ranged from 0.23 to 0.90 mg/L (mean of 0.54 mg/L); that is, the maximum recorded concentration was less than one-fifth the toxicity threshold for lignocaine of 5 mg/L. The study suggested that the majority of patients tolerated the local anaesthetic approach very well and that the wide safety margin allowed ample scope to develop the local anaesthetic approach for the repair of more complex hernia repairs (e.g. large, bilateral or strangulated herniae, or those in obese patients) without risk of exposing patients to lignocaine concentrations which may cause toxic side effects.