Prospective Study of Lidocaine, Bupivacaine and Epinephrine Levels and Blood Loss in Patients Undergoing Liposuction and Abdominoplasty

Goals/Purpose:

Bupivacaine levels have not been studied in cosmetic surgery patients to establish safety.� Blood loss from liposuction has been underestimated using the small blood volumes present in the aspirate.� There is little information available regarding safety for combined procedures.� The proportion of wetting solution removed by liposuction has not been reliably ascertained.� �Few studies have examined epinephrine levels after liposuction and/or abdominoplasty and none in conjunction with bupivacaine.¹� This study was undertaken to investigate these important safety issues.

Methods/Technique:

A prospective study was undertaken among 322 consecutive patients presenting for superwet ultrasonic liposuction (n = 229) and/or abdominoplasty (n = 93), and other combined procedures, using infusions containing 0.05% lidocaine (liposuction) and/or 0.025% bupivacaine (abdominoplasty) with 1:500,000 epinephrine.� Plasma levels of lidocaine, bupivacaine, and epinephrine were studied in a subset of 76 consecutive patients, including hourly intraoperative samples in 37 consecutive patients.� In 95 patients (29.5%) who had combined procedures (e.g., simultaneous cosmetic breast surgery or a face lift), bupivacaine was also injected as a component of the local anesthetic (Fig.1). �All patients were treated by the same surgeon (E.S.) as outpatients in a licensed ambulatory surgery center under an unconscious intravenous anesthetic administered by an anesthesiologist or certified nurse anesthetist.� Sequential compression devices were used.

Results/Complications:

There were no pulmonary emboli and no deaths.� There were two hospital admissions, one for treatment of a deep venous thrombosis and another for treatment of an infection. �Among abdominoplasty patients, there were three cases of delayed wound healing (two needing revision), two seromas treated with aspiration, and no hematomas. �No patient showed signs of fluid overload and none required fluid resuscitation beyond maintenance.

Mean heart rates and blood pressures did not fluctuate significantly during surgery.� In the postanesthesia care unit, no patient developed symptoms or signs of local anesthetic or epinephrine toxicity.�

The maximum lidocaine level dose was 3242.5 mg and level was 2.10 μg/ml.� The maximum bupivacaine dose was 549.9 mg and level 0.81 μg/ml.� No clinical toxicity was encountered.� Estimated blood loss from liposuction was 217.5 cc + 187 cc/liter of aspirate (r = 0.65, Fig. 2).� Abdominoplasty added 290 cc of blood loss, on average (Fig. 3).� The mean proportion of wetting solution removed by liposuction was 9.8%, determined by the ratio of infranatant/plasma glucose (�glucose ratio�).� The mean proportion of wetting solution in the aspirate was 10.4% (Fig. 4). �The mean hematocrit (�lipocrit�) of the infranatant fluid was 1.76%.

The maximum bupivacaine level of 0.81 μg/ml, recorded the day after surgery, was well under the toxic threshold of 3 �g/ml, suggests a comfortable margin of safety despite the use of doses exceeding traditional recommendations (analogous to lidocaine).� The finding of undetectable intraoperative plasma levels of bupivacaine in abdominoplasty patients, who typically received 250 mg (0.025%) of bupivacaine with their wetting solution, reveals profoundly delayed absorption of this anesthetic agent when it is administered in this very dilute form in the presence of 1:500,000 epinephrine.� A more concentrated epinephrine solution may provide a greater anesthetic dampening effect, evidenced by the very gradual increase in bupivacaine levels.�

Although there is minimal visible blood loss during liposuction, there is substantial extravascular (�third space�) blood loss into the interstitial tissues, accounting for 98% of the blood loss from liposuction (Fig. 5). �

Knowledge of the expected blood loss from liposuction (Fig. 2) and combination procedures (Fig. 3), commonly performed today, is useful for the surgeon planning a combined procedure, so as to lessen postoperative anemia, a common cause of morbidity.� Fat volumes under 5000 cc (maximum 4700 cc in this study)� may be safely aspirated in combination with abdominoplasty and other cosmetic procedures.

Conclusion:

Bupivacaine may be safely used in cosmetic surgery in doses up to 550 mg delivered in dilute form into the subcutaneous tissues, and in combination with lidocaine.� A concentration of 1:500,000 epinephrine is safe and effective when administered as part of a wetting solution that is limited to less than 5 liters.� Estimated blood loss is higher than previous estimates based on lipocrits and is related to aspirate volume.� Combination procedures are safe.� Effective local anesthesia combined with unconscious intravenous sedation increases safety and improves recovery.

References:

1. Burk RW, Guzman-Stein G, Vasconez LO. Lidocaine and epinephrine levels in tumescent technique liposuction. Plast Reconstr Surg. 1996;97:1379-1384.

Fig. 1.� Local anesthetic and epinephrine concentrations.�

Fig. 2.� Estimated blood loss versus liposuction aspirate volumes for patients treated with liposuction only.� A blood loss of 1153 cc is expected for a patient with 5 liters of aspirate.� Infusion alone appears to cause a 217.5 cc blood loss.

Fig. 3.� Estimated additional blood loss from specific combination procedures performed with liposuction, controlled for aspirate volume.

Fig. 4.� Mean contents of liposuction aspirate.�

Fig. 5.� Fluid shifts and changes in blood volume after liposuction. ISF, �interstitial fluid. IVF, intravascular fluid.