The terms "wetting solution" and "tumescent solution" are often used interchangeably. Of the two, "tumescent solution" is the more commonly heard terminology. The term “tumescent solution” is often used to describe the fluid that is injected or infiltrated into fat prior to liposuction. Technically, the fluid injected into the fat before it is treated with liposuction should be called “wetting solution.” The term “tumescent” actually refers to a liposuction technique. Specifically, wetting solution that is injected into fat in lesser amounts is known as “wet liposuction.” Adding more wetting solution to fat before it is suctioned is known as “superwet liposuction." Finally, the addition of even more wetting solution to the point that the skin is swollen and firm is known as “tumescent liposuction.” In short, all techniques of liposuction use wetting solution, except dry liposuction which uses no wetting solution at all.
What is the purpose of wetting solution?
The purpose of wetting solution is multi-fold:
- Reduce the need for heavy sedation or general anesthesia due to its anesthetic effect
- Reduce blood loss by narrowing/constricting blood vessels
- Reduce need for intravenous (IV) fluids for fluid resuscitation
- Allow easier passage of the liposuction cannula through the fat
How is wetting solution used in plastic surgery?
While wetting solution is primarily used for liposuction, it is also used in many other plastic surgery procedures. Examples of such procedures include breast augmentation, breast reduction, breast lift, tummy tuck, and facelift.
Wetting solution is utilized in almost all liposuction procedures. Before the introduction of wetting solution, blood loss from liposuction was so great in some instances that an overnight hospital stay and even a blood transfusion were required. Wetting solution has made the liposuction procedure much safer. Tumescent liposuction allows the removal of large volumes of fat with minimal blood loss.
What is in wetting solution?
The primary ingredient in wetting solution is either saline solution or lactated ringers solution. The saline or lactated ringers solution usually comes in a 1-liter bag. To this bag is added lidocaine, epinephrine and sometimes bicarbonate. Lidocaine is an anesthetic that numbs the areas of fat that are to be treated with liposuction. The addition of epinephrine to the saline or lactated ringers decreases blood loss by causing constriction/narrowing of blood vessels. The narrower the diameter of the blood vessel, the less they are in the way of the liposuction cannula and the less blood that comes from them.
Additionally, epinephrine slows the body’s absorption of lidocaine. This allows the lidocaine to stay around longer without having to add more tumescent solution to reduce pain. It also decreases the risk of lidocaine toxicity. Lidocaine toxicity occurs when the amount of lidocaine is too high for the body to absorb. This can lead to an irregular heartbeat, brain issues, and death. To minimize this complication, the amount of lidocaine given is based on body weight.
Sodium bicarbonate, a chemical compound, is added to the solution to decrease the acidity of the lidocaine in the wetting solution. Increased acidity is irritating to the tissues and causes more pain upon injection.
How does my plastic surgeon know how much lidocaine to use?
On the day of your surgery, your plastic surgeon will obtain your weight. There is a mathematical formula used to calculate the maximum amount of lidocaine that is acceptable for your weight. The safe range of lidocaine when used in conjunction with epinephrine as a wetting solution is 35 mg/kg to 50 mg/kg. It is my opinion that it is best to be conservative and use the lower end of the range to minimize the risk of lidocaine toxicity.
How does lidocaine work?
Lidocaine is a local anesthetic that temporarily blocks the signals at the ends of the nerves. Because the nerve endings are blocked, pain signals are not perceived. This is the “numb” sensation that occurs after injection with lidocaine.
What are the advantages of using wetting solution?
- No routine blood transfusions
- Less pain after procedure due to effects of the local anesthesia in the wetting solution
- Avoidance of post-operative nausea and vomiting associated with general anesthesia
- In the case of tumescent liposuction, reduces need for the use IV fluids