Letters to the Editor 2. Rosenberg PH, Veering BT, Urmey WF. Maximum recommended doses of local anesthetics: A multifactorial concept. Reg Anesth Pain Med 2004;29:564-575. 3. Beaulieu P, Babin D, Hemmerling T. The pharmacodynamics of ropivacaine and bupivacaine in combined sciatic and femoral nerve blocks for total knee arthroplasty. Anesth Analg 2006;103:768-774. 4. Ben-David B, Schmalenberger K, Chelly JE. Analgesia after total knee arthroplasty: Is continuous sciatic blockade needed in addition to continuous femoral blockade? Anesth Analg 2004;98:747-749. 5. Buvanendran A, Kroin JS, Tuman KJ, Lubenow TR, Elmofty D, Moric M, Rosenberg AG. Effects of perioperative administration of a selective cyclooxygenase 2 inhibitor on pain management and recovery of function after knee replacement: A randomized controlled trial. JAMA 2003;290:2411-2418. 6. Montazeri K, Kashefi P, Honarmand A. Pre-emptive gabapentin significantly reduces postoperative pain and morphine demand following lower extremity orthopaedic surgery. Singapore Med J 2007;48:748-751.
Accepted for publication February 29, 2008. doi:10.1016/j.rapm.2008.02.004
Reply to Dr. Nelson To the Editor: The patient in our case report1 weighed 80 kg and was 5 feet 4 inches tall. For her second (uneventful) anesthetic, we placed a femoral catheter and dosed it with 20 mL 0.5% ropivicaine. A sciatic block was then placed using a subgluteal approach with 20 mL 0.5% ropivacaine, thus reducing her total local anesthetic dose from 300 to 200 mg. All ropivacaine contained 1 to 200,000 epinephrine. A bupivacaine subarachnoid block was then placed. Dr. Nelson makes a valid point.2 It is our belief that our previous practice of dosing the femoral catheter then immediately placing a single shot sciatic block left little margin for avoiding toxicity. The injection of 30 mL of long-acting local anesthetic “primed” the patient with high serum levels of local anesthetic. If any bupivacaine from the subsequent sciatic block went intravascular the serum levels of local anesthetic would abruptly exceed toxic levels. We have since modified our practice. We place a femoral catheter but do not dose it. A single shot sciatic block is then placed using 20 mL to 30 mL of ropivacaine depending on the patient’s weight, age, and comorbidities. A subarachnoid block is then placed. The femoral catheter is dosed with 20 mL to 30 mL of ropivacaine approximately 2 hours later. Unless contraindicated, all our patients receive celecoxib and pregabalin (gabapentin at the time of the case report). We have excluded the sciatic block from our anesthetic/ analgesic regimen for total knee arthroplasty in some situations and feel these patients invariably have a significant amount of posterior knee pain, even with patient-controlled analgesia. It is our opinion that sciatic block with continuous femoral nerve block can be carried out safely if the dosing intervals are spread out, and that this regimen leads to a significant improvement in analgesia. Since instituting the changes in our anesthetic regimen for total knee arthroplasty we have not had any problems with local anesthetic toxicity. However, prior to the
events outlined in our case report, we had been using our old protocol for over 6 years without event. This goes to show that for very rare but potentially devastating complications such as local anesthetic cardiotoxicity, individual practices cannot assess safety using personally achieved numbers. One cannot be lulled into a false sense of security because he or she has never seen local anesthetic toxicity despite performing blocks for years. Vigilance and practices designed to minimize the chances of toxicity are of paramount importance. In addition, the knowledge and ability to treat local anesthetic toxicity is a prerequisite in the practice of regional anesthesia. Thomas M. McCutchen, M.D. Department of Anesthesiology Wake Forest University School of Medicine Winston-Salem, NC References 1. McCutchen T, Gerancher JC. Early intralipid therapy may have prevented bupivacaine-associated cardiac arrest. Reg Anesth Pain Med 2008;33:178-180. 2. Nelson T. Bupivacaine-associated cardiac arrest. Reg Anesth Pain Med 2008;33:504 –505.
Accepted for publication April 29, 2008. doi:10.1016/j.rapm.2008.04.009
Site Marking for Safer Regional Anesthesia To the Editor: Wrong-site peripheral nerve blocks are a burgeoning problem; however, the complex, draconian system endorsed in recent issues of Regional Anesthesia and Pain Medicine is not a viable solution.1-4 In 2003, the Joint Commission on the Accreditation of Healthcare Organizations (JCAHO) promulgated the Universal Protocol For Preventing Wrong Site, Wrong Procedure, Wrong Person Surgery™ (UP).5 The cornerstones of the UP are site marking and a preprocedural time out. The first major organization to advocate site marking was probably the Canadian Orthopaedic Society.6 Their motto is, “Operate through your initials.” In Canada, a decrease in wrong-site orthopedic surgery was observed after site marking was recommended by the Society in 1994.7 The UP recommends that the person doing the procedure mark the site with the involvement of the patient and family, prior to the administration of sedation. The UP requires that site marking must be visible after the patient is positioned, prepped, and draped for the procedure. For most peripheral nerve blocks, the surgical mark will not be visible after positioning the patient for the block. This is especially true for blocks done in the lateral and prone positions. Even an axillary block deserves a separate mark because the surgical mark will usually be out of sight after abducting the arm above the head. In 2005, Edmonds et al.1 reported 2 cases of wrong-site nerve blocks and described a protocol that their department enacted to address the problem. Their protocol specifically precluded separate site marking for nerve blocks