| JOURNAL HOME | CME HOME | THIS MONTH | PAST ISSUES | ETOC | COLLECTIONS |
| AUTHORS | REVIEWERS | EDITORIAL BOARD | FEEDBACK | RSS | HELP |
| ||||||||||||||
| ||||||||||||||
|
|
|
|
||||||||||||
|
||||||||||||||
Department of Anesthesia The Toronto Hospital, Western Division Toronto, Ontario, Canada M5T 2S8
We congratulate Reuben et al. (1) on their study assessing the minimally effective concentration of meperidine in IV regional anesthesia (IVRA). Unfortunately, the 30-mg dose results in excessive systemic side effects; hence, despite a significant increase in the duration of postoperative analgesia, the problems may outweigh the benefits. We wish to suggest a possible solution to this problem, using the forearm method of IVRA, a safe technique (2–4) used often at our institution.
The dose of local anesthetic required for successful blockade using the forearm method is approximately 50% of that used in the conventional technique, i.e., 0.3 mL/kg lidocaine 0.5% (approximately 20 mL), compared with 0.6 mL/kg (40 mL) (3). As the prolonged analgesia associated with meperidine is believed to be a local effect, the addition of 15 mg of meperidine to 20 mL of lidocaine for forearm IVRA should result in a similar duration of postoperative analgesia of 30 mg of meperidine diluted in 40 mL of lidocaine, for conventional IVRA. However this 15-mg dose should maintain a low side-effect profile. The forearm technique is suitable for carpal tunnel surgery and is especially useful in tenolysis, in which tendon function is preserved intraoperatively. Using 15 mg of meperidine in forearm IVRA may be beneficial in solving the problem of postoperative pain.
References
Department of Anesthesiology Baystate Medical Center Springfield, MA 01199
We appreciate the comment by Drs. Coleman and Chan suggesting that a smaller dose of meperidine (15 mg) may be beneficial when used as a component of IV regional anesthesia (IVRA) lidocaine 0.5% using a forearm tourniquet. Although prolonged analgesia with meperidine doses 
30 mg can be achieved, we believe the peak plasma meperidine concentrations that result after tourniquet release were large enough to cause the centrally mediated opioid side effects we observed (1). The incidence of these side effects was less frequent with meperidine doses 
20 mg and was found to be statistically similar to the control group. Perhaps 15 mg of meperidine in IVRA lidocaine using a forearm tourniquet provides effective postoperative analgesia with a lower incidence of side effects.
IVRA with a forearm tourniquet provides safe and effective analgesia using smaller doses of lidocaine (2–4). In addition, a forearm tourniquet may be tolerated for a longer (5) or at least equal (6) period of time as an upper arm tourniquet. However, the use of a forearm tourniquet remains controversial. Sanders (7) states that "tourniquets should never be placed distal to the elbow" because of a greater risk of nerve injury and breakthrough bleeding. A forearm tourniquet may not adequately compress the anterior and posterior interosseous arteries located between the radius and ulna, leading to a greater incidence of blood leakage (8). The use of a forearm tourniquet is not recommended for hypertensive patients because of an increased incidence of venous congestion and inadequate analgesia observed with this technique (2). Furthermore, ulnar neuropathy has been reported after the use of a forearm tourniquet (9), perhaps occurring more often than with an upper arm tourniquet. The ulnar nerve can be transfixed between the tourniquet and the ulna, and if the elbow is inadvertently flexed during surgery, a traction neuritis can develop.
Although smaller doses of meperidine and lidocaine may be used during IVRA with a forearm tourniquet, this technique should be used with caution. Moreover, the analgesic effects of meperidine in these circumstances have never been investigated.
References
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
