Answer:
The issue of fluid status becomes relevant with the larger aspirates – just what is a large aspirate? – depends on your perspective. Some say 1.5 L, others 3 L, and yet others 5 L. Anything greater than 1.5 liters resembles a burn injury physiologically and results in large fluid shifts, and needs to be monitored. Pitman recommends replacing twice the volume of aspirate. Most, if not all of this is given as subcutaneous fluid. He gives additional fluid in the recovery room only if the infusate turns out to be less than twice the aspirate. This is based on studies that have shown that up to 70% of the infused volume is absorbed and becomes intravascular. For larger liposuctions, it is imperative to carefully monitor their fluid status, place a foley, and keep patients overnight in the hospital. It is safer yet to stage the procedure and avoid this risk entirely.
Blood loss is assessed by determining what percent of the aspirate is blood and multiplying by the total amount suctioned. The dry technique results in the aspirate containing 20-45% blood – for this reason it has been abandoned. The wet technique reduces blood loss to 3-40% depending on the study – most surgeons add dilute epinephrine (1:435,000) – which shows a 50% reduction compared to plain saline. Using more fluid, as in the superwet or tumescent techniques, further decreases blood loss to about 1% of the aspirate. There have been no prospective randomized studies to define the optimal quantity of infiltrate or epinephrine to yield the beneficial effects of vasoconstrictor injection. And it is not clear at this time whether there is any advantage to the tumescent technique over the superwet.