Question: I’m coding for anesthesia during rib fixation surgery. What’s your advice on the best anesthesia code to report? Wisconsin Subscriber Answer: The most logical anesthesia code choice will depend on the specifics of the procedure. Your first step in coding is to read the documentation to gather more details for basing your selection. For example, the physician reports external rib fixation with 21899 (Unlisted procedure, neck or thorax). Because this is an “unlisted” code, it does not have a specific anesthesia crosswalk. You should report the anesthesia code that best corresponds to the procedure, which in this case could potentially be 00520 (Anesthesia for closed chest procedures; (including bronchoscopy) not otherwise specified). Note, however, that your choice will depend on the procedure details. If the physician performs open management of a rib fracture, you have other options: Each of these codes (21811, 21812, and 21813) first cross to anesthesia code 00541 (Anesthesia for thoracotomy procedures involving lungs, pleura, diaphragm, and mediastinum (including surgical thoracoscopy); utilizing 1 lung ventilation), which is a 15 base unit code. The secondary anesthesia code is 00540 (Anesthesia for thoracotomy procedures involving lungs, pleura, diaphragm, and mediastinum (including surgical thoracoscopy); not otherwise specified), which carries 12 base units.