To the Editor:—
I read with great interest the report by Carli et al. 1in which improvement in bowel motility, pain relief and other quality-of-life issues following bowel surgery were attributed to the use of intraoperative epidural anesthesia and post operative epidural analgesia. Bupivacaine when administered in the epidural space is systemically absorbed resulting in serum blood levels. Giving a “maximum of 15–20 ml in the epidural space”1of bupivacaine 0.5% and waiting for the appearance of bilateral sensory block will also result in a serum level of the local anesthetic before incision. As the control group did not receive a comparable dose of an intravenous amide anesthetic before surgery it is inappropriate to conclude that the bupivacaine works through an epidural mechanism. In a recent study, Groudine et al. 2administered intraoperative intravenous lidocaine to patients undergoing radical retropubic prostatectomy and demonstrated many of the benefits Carli et al. 1observed in their patients (faster return of bowel function and diminished pain) in addition to a shorter hospital stay without the need to administer the drug epidurally. Menigaux et al. 3demonstrated that the analgesia observed with sufentanil was dependent on plasma concentration and not route of administration (more epidural sufentanil had to be given to get the same analgesia seen with a lower intravenous dose).
Amide anesthetics have potent antiinflammatory activity, 4and this activity may play a significant role in minimizing the duration of ileus and postoperative pain. Carli et al. 1have clearly shown a benefit to giving patients an amide local anesthetic perioperatively. However, no convincing evidence was presented that this drug must be given by the epidural route to be effective.