**3. Tumescent solutions**

Currently, the most used solution to generate the tumescence is the one described by Klein [4, 7], and a more reasonable variant—which we prefer to use but little is known—is the one proposed by Hunstad [8, 9], as seen in **Table 1**.

Lidocaine toxicity is in function if the peak plasma concentration is reached, which will depend on several factors such as the total amount of mg/kg, as well as its rate of absorption and elimination, so that the peak levels of lidocaine and its active metabolite (monoethylglycinexylidide) occur in a period as variable as 8–32 h after infiltration has been done. For this reason alone, for patients who are treated with this procedure, it is not recommended to do it in an outpatient setting, because the maximum concentrations of lidocaine and its active

Anesthesia Management for Large-Volume Liposuction http://dx.doi.org/10.5772/intechopen.83630 75

Lidocaine is eliminated from the body by diethylation in the liver by isoenzyme groups 1A2 and 3A4 of cytochrome p450. Thus, all drugs that inhibit isoenzyme 3A4 and cytochrome P450 can affect the metabolism of lidocaine. For this reason, lidocaine doses should be reduced in patients who use medications that interfere with the cytochrome P450 system or that affect the hepatic blood flow. The factors that can modify the systemic absorption of lidocaine need to be considered. Obviously, the reached concentration of the drug, the degree of vascularity of the infiltrated tissue, the concomitant use of vasoconstrictor drugs, and the infiltration rate

The adequate use of epinephrine in the tumescent solution theoretically allows blood loss to be 1–2% of the total volume aspirated. The maximum recommended total dose of epinephrine is 0.07 mg/kg. Vasoconstrictors are used to reduce blood circulation in the tissues, which helps to slow the absorption of local anesthetics. Adrenaline is the most commonly used vasoconstrictor; the recommended concentration for the tumescent solution ranges from 0.25 to 1 mg/ Lt, depending on the tissue vascularity in question. In more vascularized tissues, the recommended concentration is 1 mg/L to be decreased to 0.5 mg/L in body areas with less vascularization (**Figure 3**). If it is anticipated that this maximum dose will be exceeded, the procedure

**Figure 3.** Infiltrated back. Note the changes in skin circulation due to the tumescent solution, with a marked delay in

metabolite will most often take the patient at home with little vigilance.

[3] are very important.

capillary refill.

In the tumescent solution described by Klein, the local anesthetic was diluted in isotonic saline solution. However, when isotonic saline solution is used as a diluent, if the patient is not under anesthesia, a burn sensation will be reported as the solution is infiltrated. It is reasonably recommended that when using this solution, the acidic pH of the 0.9% saline solution should be neutralized with bicarbonate, which in addition reduces pain; by increasing the pH, it also increases the proportion of non-ionized lipid soluble lidocaine, which favors a faster entry into the nerve cell where lidocaine acts. When lactate Ringer's solution is used, this burning sensation does not occur upon infiltration, and the sodium load is reduced. It should be noted that the dose of lidocaine and epinephrine should be regulated according to the maximum doses to be considered as safe.

Regarding the local anesthetics used, there are reports with articaine or prilocaine. Liposuction done with up to 38.2 mg/kg bodyweight of articaine HCl produced plasmatic concentrations as high as 1719–7292 ng/mL, without symptoms of systemic toxicity which could be explained by the rapid hydrolysis through the plasmatic esterases. These data show that articaine is safe for infiltration during liposuction [10]. The groups that have reported the use of prilocaine have not detected elevated levels of it in plasma or methemoglobinemia [11, 12], although Yildirim et al. described a patient with 40% methemoglobinemia that developed 8 h after liposuction was performed with almost 1000 mg of prilocaine [13]. In our surgical facility, the most used local anesthetic is lidocaine, and even though for other applications when used in association with epinephrine, the maximum limit is established at 7 mg/kg. In the specific case of the tumescent solution for liposuction, the safety range is 35–55 mg/kg [14, 15]. We prefer to stay at the lower limit of 35 mg/kg in order to be more cautious, given that since the surgical team does not keep accurate control of the injected lidocaine or takes into consideration possible drug interactions or special conditions of the patient. The concentrations of lidocaine vary according to the vascularity of the area in which the liposuction is to be performed. In more sensitive or vascularized areas such as the chest and abdomen, the concentration or amount of local anesthetic mass can be increased and decreased in less sensitive areas such as the thighs.


**Table 1.** Tumescent solution.

Lidocaine toxicity is in function if the peak plasma concentration is reached, which will depend on several factors such as the total amount of mg/kg, as well as its rate of absorption and elimination, so that the peak levels of lidocaine and its active metabolite (monoethylglycinexylidide) occur in a period as variable as 8–32 h after infiltration has been done. For this reason alone, for patients who are treated with this procedure, it is not recommended to do it in an outpatient setting, because the maximum concentrations of lidocaine and its active metabolite will most often take the patient at home with little vigilance.

**3. Tumescent solutions**

74 Anesthesia Topics for Plastic and Reconstructive Surgery

proposed by Hunstad [8, 9], as seen in **Table 1**.

the maximum doses to be considered as safe.

**Klein solution Hunstad solution**

50 mL, 1% lidocaine 50 mL lidocaine 1%

1 mL (1: 1000 epinephrine) 1 mL (1: 1000 epinephrine)

1000 mL isotonic saline solution 1000 mL Ringer's lactate solution

as the thighs.

12.5 mL (8.4% sodium bicarbonate)

**Table 1.** Tumescent solution.

Currently, the most used solution to generate the tumescence is the one described by Klein [4, 7], and a more reasonable variant—which we prefer to use but little is known—is the one

In the tumescent solution described by Klein, the local anesthetic was diluted in isotonic saline solution. However, when isotonic saline solution is used as a diluent, if the patient is not under anesthesia, a burn sensation will be reported as the solution is infiltrated. It is reasonably recommended that when using this solution, the acidic pH of the 0.9% saline solution should be neutralized with bicarbonate, which in addition reduces pain; by increasing the pH, it also increases the proportion of non-ionized lipid soluble lidocaine, which favors a faster entry into the nerve cell where lidocaine acts. When lactate Ringer's solution is used, this burning sensation does not occur upon infiltration, and the sodium load is reduced. It should be noted that the dose of lidocaine and epinephrine should be regulated according to

Regarding the local anesthetics used, there are reports with articaine or prilocaine. Liposuction done with up to 38.2 mg/kg bodyweight of articaine HCl produced plasmatic concentrations as high as 1719–7292 ng/mL, without symptoms of systemic toxicity which could be explained by the rapid hydrolysis through the plasmatic esterases. These data show that articaine is safe for infiltration during liposuction [10]. The groups that have reported the use of prilocaine have not detected elevated levels of it in plasma or methemoglobinemia [11, 12], although Yildirim et al. described a patient with 40% methemoglobinemia that developed 8 h after liposuction was performed with almost 1000 mg of prilocaine [13]. In our surgical facility, the most used local anesthetic is lidocaine, and even though for other applications when used in association with epinephrine, the maximum limit is established at 7 mg/kg. In the specific case of the tumescent solution for liposuction, the safety range is 35–55 mg/kg [14, 15]. We prefer to stay at the lower limit of 35 mg/kg in order to be more cautious, given that since the surgical team does not keep accurate control of the injected lidocaine or takes into consideration possible drug interactions or special conditions of the patient. The concentrations of lidocaine vary according to the vascularity of the area in which the liposuction is to be performed. In more sensitive or vascularized areas such as the chest and abdomen, the concentration or amount of local anesthetic mass can be increased and decreased in less sensitive areas such Lidocaine is eliminated from the body by diethylation in the liver by isoenzyme groups 1A2 and 3A4 of cytochrome p450. Thus, all drugs that inhibit isoenzyme 3A4 and cytochrome P450 can affect the metabolism of lidocaine. For this reason, lidocaine doses should be reduced in patients who use medications that interfere with the cytochrome P450 system or that affect the hepatic blood flow. The factors that can modify the systemic absorption of lidocaine need to be considered. Obviously, the reached concentration of the drug, the degree of vascularity of the infiltrated tissue, the concomitant use of vasoconstrictor drugs, and the infiltration rate [3] are very important.

The adequate use of epinephrine in the tumescent solution theoretically allows blood loss to be 1–2% of the total volume aspirated. The maximum recommended total dose of epinephrine is 0.07 mg/kg. Vasoconstrictors are used to reduce blood circulation in the tissues, which helps to slow the absorption of local anesthetics. Adrenaline is the most commonly used vasoconstrictor; the recommended concentration for the tumescent solution ranges from 0.25 to 1 mg/ Lt, depending on the tissue vascularity in question. In more vascularized tissues, the recommended concentration is 1 mg/L to be decreased to 0.5 mg/L in body areas with less vascularization (**Figure 3**). If it is anticipated that this maximum dose will be exceeded, the procedure

**Figure 3.** Infiltrated back. Note the changes in skin circulation due to the tumescent solution, with a marked delay in capillary refill.

should be done replacing the adrenaline with other options such as 1-ornithine-8-vasopressin in concentrations of 0.01 IU/ml, with the disadvantage of having to use it in unheated solution with the consequent hypothermia of the patient.

**6. Anesthesia management**

is optional during the surgery.

While liposuction of large volumes can be done with any anesthesia technique, we strongly recommend the use of general anesthesia. The anesthetic induction is done in the usual way, being propofol the most used drug. For muscular relaxation for endotracheal intubation, a non-depolarizing drug with rapid action such as rocuronium or atracurium, although vecuronium is probably the most used muscle relaxants due to its safety and low cost. For the maintenance of anesthesia, desflurane, sevoflurane or isoflurane alone or in combination with opioids can be used. Ketofol have been recommended by several authors. Muscle relaxation

Anesthesia Management for Large-Volume Liposuction http://dx.doi.org/10.5772/intechopen.83630 77

In our experience, which is worth taking into consideration, since in the last 8 years, we have accumulated an average of 200 large-volume liposuctions per year (with the peculiarity that it is the same surgeon and the same anesthesiologist). We usually premedicate patients with ranitidine, metoclopramide, ondansetron, and the prophylactic antibiotic of the surgeon's choice. Induction is with fentanyl 3–4 mμ/kg and vecuronium to facilitate orotracheal intubation (usually 4–6 mg) and propofol 2 mg/kg. We continue with inhalatory anesthesia with low flows, in general terms only use oxygen 350 to maximum 400 mL/minute, and desflurane given its faster response to modify the desired CAM. As approximately 60–70% of the time, the procedure will be done with the patient facing down, more when it includes lipoinjection in the buttocks. The patient is intubated orotracheally with a spiral reinforced cuffed tracheal tube (like Sheridan Spiral-Flex®) properly fixed. We never relied on a laryngeal mask; no matter the discussion, it will never approach the security provided by an endotracheal tube. Due to the situation of changes in the patient's position, experience is necessary in turning the patient from supine to the ventral position and ventral to the supine, protecting the cervical spine and ensuring that the endotracheal tube does not move. It is necessary to have protection devices for pressure points, which allows us to keep the patient upside down, taking care

The patient scheduled for liposuction at least qualifies as a moderate thromboembolic risk, so all of them must have compression stockings and intermittent pneumatic compression systems installed, both during surgery and during all the time that they remain in the clinic or at least until they start ambulation. In special cases of higher risk, pharmacological throm-

As for the monitoring equipment, beyond the required pulse oximetry, ECG with automated analysis of the ST segment, noninvasive blood pressure measurement every 5 minutes, capnography, and analysis of inhaled and exhaled gases, if available. As for temperature monitoring is useful to keep the record in two channels, central and peripheral temperature, since the isolated reading of the peripheral is of little use, it is more advisable to have both readings and be aware of the gap between the two. Although we have neuromuscular relaxation monitor, given the type of surgery, the low doses of the neuromuscular blocking agents injected for the tracheal intubation and its pharmacokinetic profile, at the end of the surgery, have no residual effects. BIS or entropy monitor can be very useful, given that the hemodynamic variations of the patients are not rare as a result of the adrenergic stimuli due to the infiltrated

of pressure points on the nose and eyes fundamentally (**Figure 4**) [16].

boprophylaxis with low-molecular-weight heparin is necessary.
