- □ (A) Third-space crystalloid redistribution
- □ (B) Epinephrine added to the tumescent solution
- □ (C) Postprocedure blood loss
The tumescent liposuction technique uses large volumes of a dilute solution of lidocaine (0.05%-0.10%) with epinephrine (1:1,000,000) in normal saline to swell and harden the target tissue. This technique results in long-lasting local anesthesia and a delay in the peak plasma concentration of lidocaine. This delay occurs because of the addition of epinephrine. Some procedures (e.g., breast surgery) use tumescent liposuction without epinephrine. In such cases, peak plasma concentration of lidocaine occurs within one to two hours after injection.
The safe dose of lidocaine using the tumescent technique (with epinephrine) has been reported to be 35 mg/kg, with some advocating as high as 55 mg/kg, compared to the usual recommended infiltration dose of 7 mg/kg (when used with 5 μg/mL of epinephrine). The dilute epinephrine dose causes a constriction of the blood vessels, leading to a peak lidocaine dose occurring 12 to 14 hours after the procedure. The accompanying vascular constriction (and the paucity of blood flow to fat tissues) results in little blood loss. In the scenario presented, the delay in the peak concentration of lidocaine is most likely due to the addition of dilute epinephrine to the tumescent solution.
Reabsorption of the crystalloid portion of the tumescent solution occurs slowly, again due to the meager blood supply of the fat layer and the addition of epinephrine. It is unlikely that redistribution of crystalloid or blood loss would be the proximate cause of the delay between the injection of lidocaine and this patient’s postprocedural seizure.
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