Dr. Pace et al. revive an old prejudice against bupivacaine.1 Their article echoes Klein’s objections that were published in the Journal in 1998.2 The authors contend that “there is evidence to support the avoidance of bupivacaine in infiltrate solution recipes because of the potential for fatal complications of toxicity.” However, they do not reference any examples of adverse effects when bupivacaine is administered in this manner. The authors offer no data of their own or personal experience with this anesthetic agent.
Bupivacaine has been used for decades in plastic surgery. To date, there has been not a single reported case of toxicity from its use in wetting solutions. My investigation, published last year and referenced by the authors, represents the only study to actually measure levels of this anesthetic agent in plastic surgery patients. The maximum plasma level was 0.81 μg/ml, well below the toxic threshold of approximately 3 μg/ml, with no evidence of toxicity.3
The authors acknowledge that “the risk of toxicity from any local anesthetic is lower when uptake into the systemic circulation is gradual.”1 Plasma assays reveal a very slow absorption of bupivacaine, much slower than lidocaine.3 Bupivacaine is not even detected in the circulation until 4 hours after its infusion into the abdominal fat layer. Its level rises very gradually over 20 hours, and it may still be detectable in the plasma at 48 hours (Fig. 1). This profoundly delayed release into the circulation is not just an effect of epinephrine, which would be expected to delay lidocaine and bupivacaine absorption equally. Bupivacaine partitions more readily into fat than lidocaine. Small amounts of bupivacaine enter the circulation from this fat tissue reservoir—a sort of physiologic pain pump—incrementally over a period of more than 2 days. Bupivacaine’s greater affinity for fat is an important advantage over other, less lipophilic local anesthetics such as lidocaine, in terms of both efficacy and safety (i.e., more in the tissues, less in the blood). Studies of intradermal injections that suggest only a small prolongation of anesthesia for bupivacaine in the presence of epinephrine4 cannot be extrapolated to infusions into the fat layer.
My practice is to limit the use of bupivacaine in wetting solutions to infusion of the abdomen before abdominoplasty, a procedure that causes more postoperative pain than liposuction alone.3 Failey et al. report that lipoabdominoplasty patients who received bupivacaine wetting solutions had significantly shorter hospitalizations than a control group of patients who received lidocaine or saline infusions.5 This serendipitous finding is not surprising in view of bupivacaine’s well-known potency, prolonged duration of action, and, perhaps most importantly, affinity for fat tissue. In my series of 322 consecutive liposuction and abdominoplasty outpatients,3 there were no hospital admissions for uncontrolled pain or nausea. Recovery room times averaged 51 minutes. Effective and durable anesthesia at the tissue level hastens recovery and minimizes the need for systemic medications and their adverse side effects. Effective peripheral anesthesia also avoids the need for rib blocks, subfascial injections, and pain pumps, all of which introduce complications of their own.
The authors speculate about possible toxicity from cerebral ion trapping if anesthetized patients develop respiratory acidosis.1 In my study, carbon dioxide levels in the blood remained normal, and there were no cases of neurologic toxicity.3 The real clinical issue is actually respiratory alkalosis (causing hypokalemia), which is why spontaneous breathing is preferred over mechanical ventilation.3 Of course, precipitation of bupivacaine is easily avoided by not adding sodium bicarbonate to infusions.
The authors reproduce Klein’s formula (without sodium bicarbonate) and describe a linear relationship between patient weight and the maximum infiltrate volume.1 In practice, there is no need to infuse more than 5 liters. A 0.05% lidocaine solution is already the standard. More dilute concentrations, in the range of 0.01% to 0.05%, are unnecessary and may compromise efficacy.
The authors caution that mixing lidocaine and bupivacaine, a common practice among plastic surgeons for decades,3,5 is not supported by the U.S. Food and Drug Administration because of insufficient clinical data. In fact, such data are now available.3 These guidelines do not always reflect the most recent literature; this federal agency still does not recognize the safety of lidocaine doses greater than 7 mg/kg, either.
Evidence-based medicine calls for the use of the best available evidence in making clinical recommendations, as opposed to relying on old prejudices or unsupported opinions. Our efforts should be directed toward real causes of patient morbidity and mortality6 rather than hypothetical ones. Complications from oversedation typically occur within the first 24 hours after surgery.6 By extending tissue anesthesia, bupivacaine may reduce the need for systemic medications during this critical time period and avoid patient overmedication for pain control. Its unique characteristics make bupivacaine a valuable asset in plastic surgery to optimize analgesia and improve patient safety.
The author has no conflicts of interest to disclose. There was no outside funding for this study.
Eric Swanson, M.D.
11413 Ash Street
Leawood, Kans. 66211
1. Pace MM, Chatterjee A, Merrill DG, Stotland MA, Ridgway EB. Local anesthetics in liposuction: Considerations for new practice advisory guidelines to improve patient safety. Plast Reconstr Surg. 2013;131:820e–826e.
2. Klein JA. Intravenous fluids and bupivacaine are contraindicated in tumescent liposuction. Plast Reconstr Surg. 1998;102:2516–2519.
3. Swanson E. Prospective study of lidocaine, bupivacaine and epinephrine levels and blood loss in patients undergoing liposuction and abdominoplasty. Plast Reconstr Surg. 2012;130:702–722 discussion 723–725
4. Howe NR, Williams JM. Pain of injection and duration of anesthesia for intradermal infiltration of lidocaine, bupivacaine, and etidocaine. J Dermatol Surg Oncol. 1994;20:459–464.
5. Failey CL, Vemula R, Borah GL, Hsia HC. Intraoperative use of bupivacaine for tumescent liposuction: The Robert Wood Johnson experience. Plast Reconstr Surg. 2009;124:1304–1311.
6. Grazer FM, de Jong RH. Fatal outcomes from liposuction: Census survey of cosmetic surgeons. Plast Reconstr Surg. 2000;105:436–446; discussion 447.
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