Anesthesia Units

Anesthesia is not priced like the rest of medicine. Instead of a flat fee per procedure, the anesthesia bill is built from units. Each anesthesia code carries a fixed number of base units that reflect how hard the case is, and then time units are added at one unit per 15 minutes the anesthesiologist is with you. The total units are multiplied by a dollar amount per unit, called the conversion factor, that the plan and the anesthesia group have negotiated.

Here is the arithmetic on a total knee. The anesthesia code for it, 01402, carries 7 base units. A typical case runs about two hours, which is 8 time units. That makes 15 units. If the carrier's contracted conversion factor for that anesthesia group is $75 a unit, the anesthesia bill is $1,125. At $110 a unit, which is not unusual for a hospital-based group in a big Texas city, the same case is $1,650. The conversion factor is the number that matters, and it is published in the carrier's transparency file under the anesthesia group's own provider number, not the hospital's. A surgery center's bundled cash price already includes anesthesia, which is one reason those prices are easier to trust.

The takeaway: for a scheduled surgery, ask the anesthesia group for its base units, its expected time, and the conversion factor for your plan. Three numbers, one multiplication, and the anesthesia bill stops being a surprise.