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Department of Surgery/Anesthesia, University of South Carolina, School of Medicine, Columbia, SC, dejong@nuvox.net
To the Editor:
Dr. Tabboush’s alert (1) regarding the lack of comprehensive guidance for perioperative management of liposuction in the anesthesia literature is all the more timely on the heels of last month’s "Practice Advisory on Liposuction" for plastic surgeons (2). Recent hard data from Florida underscore the substantial number of adverse events linked to office-based cosmetic procedures, with liposuction accounting for 2 of the 5 fatalities (3). In North America alone, well over 300,000 liposuctions are performed annually under "tumescent anesthesia" (a catchy name for field block with diluted lidocaine solution, sufficient to distend overlying skin), mostly in dermatology offices. As Klein (4) demonstrated in 1987, highly diluted lidocaine (0.1% or less; with 1 mg epinephrine added to each liter of solution) infiltrated subcutaneously in large volumes, presents with a pharmacokinetic profile altogether different from that of out-of-the-bottle lidocaine (1% or 2%) as used for perineural or epidural anesthesia by anesthesiologists. Tumescent (i.e., highly diluted) lidocaine, rather than being absorbed rapidly—as evidenced by the familiar early plasma concentration peak—instead is absorbed only very slowly—as shown by a leisurely rise in plasma concentration to a plateau well below 2 mg/L (2 µg/mL)—but a plateau that remains increased for the next dozen hours or so (4).
As a direct result of prolonged tissue lidocaine retention, postoperative analgesia lasts through the night. Epinephrine-induced vasoconstriction, moreover, not only slows lidocaine absorption to a crawl, thus allowing the conventional maximum lidocaine dose of 7 mg/kg to be exceeded severalfold (35 mg/kg is said to be a "safe" dose for tumescent infiltration, and amounts of 50 mg/kg lidocaine or more are administered not uncommonly), but also minimizes blood loss to <1% of total suction aspirate. The enormous lidocaine load to be disposed (often 3000 mg or more), conversely, leaves the recovering patient with a persistently elevated (albeit subtoxic) residual lidocaine level in the postoperative period, because the liver is capacity-limited to clear 250 mg lidocaine per hour at most (5). By the same token, drug competition for CYP450 active sites by patient medications such as antidepressants or anxiolytics, and by perioperative sedatives and analgesics, may slow their disposition in turn.
As Dr. Tabboush points out (1) liposuction has an acceptable, albeit not sterling, safety record: serious complications, including fatalities, continue to be reported (6). I agree with proponents of tumescent field block that—used as the sole unsupplemented anesthetic technique—large volumes of highly diluted lidocaine can provide solid, long-lasting, and relatively safe surgical analgesia. However, patient demand for "awake sedation" in the fiercely competitive free-enterprise world of cosmetic surgery may seriously degrade that safety—even more so because "unconscious sedation" all too easily may go unrecognized in facilities short on dedicated patient monitoring personnel.
As Dr. Vila and fellow anesthesiologists (3) discovered from Florida Medical Board data, cosmetic procedures were the leading source of adverse events in ambulatory patients. And, food for thought, liposuction was the most frequent offender in this category. Moreover, procedures performed in medical offices carry a more than 10 times higher risk factor than those done in better equipped and staffed ambulatory surgery facilities. Because the majority of tumescent anesthetics for liposuctions are administered in medical offices, commonly by operators unfamiliar with physician anesthesia, anesthesiologists seldom, with some exceptions (7), participate in the perioperative management of liposuction patients; all too often a medical office assistant tends to the patient as part of numerous other responsibilities. Because so little comprehensive information exists in our literature, anesthesiologists must turn elsewhere for basic guidance in this daunting field (2,5,7); it is time for our specialty to boldly address these troubling patient safety concerns.
References
Department of Anesthesiology, Kingdom Hospital, Riyadh, Saudi Arabia, Zafer@cyberia.net.lb
In Response:
We appreciate the interest of Dr. de Jong in our recent publication about tumescent anesthesia (1) and consider his comment a valuable response to our alert.
In his letter, Dr. de Jong agrees with us that there is a lack of information about tumescent anesthesia in our specialty literature. We emphasize that the need for such information is increasing, due to the recent expanded use of tumescent anesthesia to involve the pediatric group of patients (2).
In view of the reported tumescent anesthesia-related complications, we agree with Dr. de Jong that "it is time for our specialty to boldly address the troubling patient safety concerns." The fact, mentioned by Dr. de Jong, that the majority of tumescent anesthetics for cosmetic procedures are not performed in adequately equipped and staffed ambulatory surgery facilities mandates not only to address our alert, but also to seek from anesthesia societies standards and requirements that should be met when tumescent anesthesia is used.
References
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