Comparison of 40 milliliters of 0.25% intrapleural bupivacaine with epinephrine with 20 milliliters of 0.5% intrapleural bupivacaine with epinephrine after cholecystectomy. 
To determine the influence of the volume of local anesthetic injected for intrapleural analgesia, 40 patients undergoing cholecystectomy were randomly allocated to two groups of 20 patients each.  One group received 40 mL of 0.25% bupivacaine with epinephrine injected intrapleurally postoperatively.  The other group received 20 mL of 0.5% bupivacaine with epinephrine.  The onset time of analgesia was nearly the same in both groups and within 25 min all patients were nearly pain free.  Our data demonstrate that 100 mg of bupivacaine with epinephrine elicits effective analgesia after cholecystectomy.  There are only minor differences between 20 and 40 mL with regard to pain relief.  The authors conclude that the volume of local anesthetic within the range of 20-40 mL in an adult has little influence on the extent or duration of intrapleural analgesia.