Intercostal nerve blockade with a mixture of bupivacaine and phenol enhance the efficacy of intravenous patient-controlled analgesia in the control of post-cholecystectomy pain

Prolonged nerve conduction blockade has been proposed to result from the summed effects of charged and neutral local anaesthetics. Thirty-seven patients were randomly allocated to receive intravenous patient-controlled analgesia alone or combined with intercostal blockade (T7–T11) with a mixture of 0.45% bupivacaine and 0.6% phenol for post-cholecystectomy analgesia. Adequacy of pain relief was measured by patient scores on a 10-cm visual analogue scale and by dose–demand ratio, amounts of loading dose and total consumption of morphine and also the duration of patient-controlled analgesia in each group. No differences were found between groups in post-operative scores, dose–demand ratios and loading doses of morphine. However, in the combined treatment group, a significantly lower total consumption of morphine (P