Anesthesia Time, Qualifying Circumstances, and Multiple Procedures
A 71-year-old ASA-PS 3 patient with severe COPD undergoes an open reduction and internal fixation of a distal radius fracture in an ASC. The anesthesiologist provides general anesthesia. Anesthesia start time is 08:02; anesthesia end time is 09:41. The surgeon also performs a closed reduction of a separate distal phalanx fracture of the same hand during the same anesthetic. The anesthesia record documents: ASA-PS 3, controlled hypotension used to reduce bleeding, and that the patient is a former smoker with COPD. The anesthesiologist personally performed the pre-anesthetic evaluation and medically directed two CRNAs who each performed portions of the case under medical direction (the anesthesiologist was present for induction and emergence). The payer follows standard Medicare anesthesia rules.
1. Calculate the anesthesia time units and identify the base units and qualifying circumstance codes that apply.
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Time: 08:02 to 09:41 = 99 minutes. Under standard Medicare rules, anesthesia time is reported in 15-minute increments, and a fraction of 10 minutes or more rounds up to the next unit. 99 minutes ÷ 15 = 6.6 → 6 full units plus 9 remaining minutes. Because the remaining 9 minutes is less than 10, it does not round up; time units = 6. (If the remainder had been 10 or more, it would round to 7.)
Base units: The primary procedure is ORIF distal radius. Anesthesia base units are assigned per the ASA Relative Value Guide / CMS anesthesia base unit file for the specific procedure code. The coder must look up the base units for the ORIF code rather than assume a value.
Qualifying circumstances: Controlled hypotension is a qualifying circumstance → 99100 (anesthesia for patient of extreme age, under 1 year or over 70) does NOT apply merely because of age 71 - extreme age is a qualifying circumstance only for patients under 1 year or over 70, and 71 qualifies. So 99100 applies. Controlled hypotension → 99135 (controlled hypotension) applies. Note: 99100 and 99135 are each reported once and are add-on codes to the anesthesia code.
Not qualifying: COPD/former smoker and ASA-PS 3 are reflected in the ASA physical status modifier (e.g., AA or QK depending on direction), not as qualifying circumstance codes. Do not report 99100 based on ASA-PS.
2. Explain how the anesthesia service should be reported given the medical direction of two CRNAs, and which modifiers apply.
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Under Medicare medical direction rules, when an anesthesiologist medically directs more than one CRNA concurrently, the anesthesia service is billed at 50% of the allowed amount, and the appropriate modifier is QK (medical direction of two, three, or four concurrent anesthesia procedures). The anesthesiologist reports the anesthesia code with modifier QK.
The anesthesiologist must document and personally perform the seven steps of medical direction (pre-anesthetic exam, prescribing the anesthesia plan, participating in the most demanding procedures including induction and emergence, monitoring, remaining physically available, providing post-anesthesia care, and remaining available until discharge). The scenario states the anesthesiologist was present for induction and emergence, which supports medical direction.
If the anesthesiologist had personally performed the entire case without a CRNA, modifier AA would apply and full payment would be allowed. If a single CRNA were medically directed, modifier QK would not apply; QY (one CRNA) would apply at 50%. Because two CRNAs were involved, QK is correct.
The second procedure (closed reduction of phalanx) performed during the same anesthetic does not generate a separate anesthesia charge - anesthesia is billed once for the anesthetic episode, with base units reflecting the most complex procedure and additional procedures addressed per payer policy (generally the highest base unit procedure is used).
3. The coder proposes adding 99100 for age and 99135 for controlled hypotension and also adding a separate anesthesia code for the closed reduction. Assess this proposal.
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Adding 99100 is appropriate: the patient is 71, and 99100 covers patients over 70 (or under 1 year). Adding 99135 for controlled hypotension is also appropriate because controlled hypotension is documented and is a recognized qualifying circumstance.
Adding a separate anesthesia code for the closed reduction is not appropriate. Anesthesia is reported once per anesthetic episode; multiple surgical procedures performed under a single anesthetic do not each generate a separate anesthesia code. The base units are determined by the procedure with the highest base value, and additional procedures are handled per payer policy (some payers allow additional base units for multiple procedures, but a separate full anesthesia charge is not standard).
Also note the qualifying circumstances are add-on codes reported once each, not per procedure. The final claim should reflect: the primary anesthesia code with QK modifier, time units of 6, base units per the RVG, plus 99100 and 99135.