[Combined sciatic nerve/3-in-1 block. I. Dose determination for CO2-lidocaine 1.1%]

The goal of this open-labeled clinical study on 30 patients was to find out which dosage of CO2-lidocaine 1.1% (= lidocaine HCl 1%) would provide clinically acceptable analgesia for surgical procedures on the lower extremities under combined sciatic-femoral block. A first group of 5 patients was given a dose of 330 mg = 30 ml (15 ml to block the sciatic nerve and 15 ml for the 3-in-1 block), the maximum dose allowed by the manufacturer. This dosage did not result in any degree of satisfactory block and all patients had to be operated upon under general anaesthesia (GA). In a second group of 15 patients, a dose of 440 mg = 40 ml was given (sciatic nerve: 17 ml; 3-in-1 block: 23 ml). This dosage gave much better results, but 4 of 15 patients still needed light GA for supplementation. Only in the third group of 10 patients, who were given 550 mg = 50 ml (sciatic nerve: 20 ml; 3-in-1 block: 30 ml) was a clinically acceptable success rate achieved; there was only 1 patient who needed light GA for supplementation. In group I (330 mg) only partial sensory blockade was achieved (after approx. 5 min); the femoral and lateral femoral cutaneous nerves could not be blocked in any patient, and motor blockade was present in only 1 patient. In group 2 (440 mg) the onset of sensory block began after 5 min, was complete by 11 min, and in 6 of 15 patients (= 40%) motor blockade was achieved.(ABSTRACT TRUNCATED AT 250 WORDS)