Health Information Management

Coding essentials for HBO therapy

JustCoding News: Outpatient, August 22, 2012

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Some wounds and conditions don’t respond to conventional therapies and treatment modalities. In those cases, providers may consider hyperbaric oxygen therapy (HBO).

HBO is a modality in which the patient’s entire body is exposed to oxygen under increased atmospheric pressure, says Todd Sommer, DO, DPM, CWS, medical director of St. Vincent Hospital's Center for Wound Care and Hyperbaric Medicine in Green Bay, Wis. The patient is entirely enclosed in a pressure chamber breathing 100% oxygen at greater than one atmosphere (atm) pressure.
HBO therapy is not a first-line therapy, says Gloria MillerCPC, CPMA, vice president of reimbursement services at Comprehensive Healthcare Solutions, Inc. in Tacoma, Wash. Physicians will only consider HBO therapy for patients with chronic wounds or conditions after they don’t improve for 30 consecutive days under standard treatment. The standard treatment varies based on the type of wound.
Different types of wounds also require different lengths of treatment. For example, osteoradionecrosis and soft tissue radionecrosis both typically require up to 60 treatments, which equates to three months of treatment. However, these are only guidelines. Ultimately, physicians base the decision whether to continue treatment on medical necessity.
Conditions approved for HBO treatment
Not all types of wounds will benefit from HBO therapy, Sommer says. Medicare will cover HBO therapy for the following 14 conditions:
  1. Acute carbon monoxide intoxication
  2. Decompression illness
  3. Gas embolism
  4. Gas gangrene
  5. Acute traumatic peripheral ischemia
  6. Crush injuries and suturing of severed limbs
  7. Progressive necrotizing infections (necrotizing fasciitis)
  8. Preparation and preservation of compromised skin grafts
  9. Chronic refractory osteomyelitis
  10. Osteoradionecrosis
  11. Soft tissue radionecrosis
  12. Cyanide poisoning
  13. Actinomycosis
  14. Diabetic wounds of the lower extremities in patients who have type I or type II diabetes and a lower extremity wound that is due to diabetes; has a wound classified as Wagner grade III or higher; and have failed an adequate course of standard wound therapy
Not every provider treats all of these conditions. In addition, some studies suggest that HBO therapy can help patients with other conditions. At St. Vincent, Sommer says providers use HBO to treat:
  • Chronic diabetic wounds
  • Treatment of compromised skin grafts or flaps
  • Acute peripheral arterial insufficiency
  • Acute traumatic peripheral ischemia
  • Crush injuries
  • Reattachment of severed limbs
  • Delayed radiation injury
    • Osteoradionecrosis
    • Soft tissue radionecrosis
  •  Infections
    •  Chronic refractory osteomyelitis
    •  Progressive necrotizing infections
Diabetic foot ulcer
The most common condition treated with HBO therapy is a Wagner Grade 3 or higher diabetic foot ulcer, Miller says. Medicare requires that the patient have a primary or secondary diagnosis of diabetes and a lower extremity Wagner Grade 3 or higher ulcer. Wagner grades are similar to stages for pressure ulcers, Miller says. A Grade 3 ulcer is defined as a deep ulcer with an abscess or osteomyelitis.
In addition, the patient must receive standard wound care for 30 days and be unresponsive to that wound care. As part of the standard wound care in patients with diabetic ulcers, physicians:
  • Debride the ulcer to remove devitalized tissue
  • Maintain a clean, moist bed of granulation tissue with appropriate moist dressings
  • ·Perform appropriate off-loading
  • Treat any infection that might be present
In order to be eligible for HBO, patients must show no signs of healing. Physicians must also consider revascularization before beginning HBO therapy. So the patient must either see a vascular surgeon or have been told he or she is not a candidate for revascularization, Miller says
Typically, patients with diabetic foot ulcers who receive HBO undergo 40-60 treatments, which is two to three months of treatment. Providers should perform a utilization review after every 20 treatments or once a month to document how the patient is responding to HBO therapy, Miller says.
Not every diabetic foot ulcer patient is going to need HBO therapy because some will respond to standard wound care or the patient’s injury is not severe enough, Miller says.
Chronic refractory osteomyelitis
Patients who have a diabetic foot ulcer may also have chronic refractory osteomyelitis, which is a bone infection, Miller says. Typically, chronic refractory osteomyelitis requires 40 days of HBO treatment to heal.
Patients may have osteomyelitis anywhere in their bodies, not just as a result of a diabetic foot ulcer, and still be eligible for HBO therapy. For example, chronic refractory osteomyelitis could arise from a sacral ulcer.
Medicare requires patients with chronic refractory osteomyelitis to meet all of the following criteria before they can begin HBO therapy:
  • Treated with antibiotics in the past
  • Had bone resection surgery and failed to respond to the surgical debridement of non-viable bone
  • Confirmed diagnosis by positive x-ray, bone scan, MRI, or biopsy
  • Recurrent despite treatment
Some Medicare contractors require six months of treatment, while others do not specify treatment duration, Miller says. Check your local coverage determinations to find out if your MAC sets a specific amount of time and make sure you have documentation of that length of treatment prior to starting HBO.
Also keep in mind that whatever diagnosis the patient begins treatment under is the one that should be used throughout the course of treatment. If the patient begins HBO therapy for a diabetic foot ulcer and the physician later adds a diagnosis of chronic refractory osteomyelitis, coders should continue to report diabetic foot ulcer as the diagnosis throughout the treatment, Miller says.
Osteoradionecrosis and radiation soft tissue necrosis
Osteoradionecrosis patients suffer bone degeneration after being exposed to radiation. For example a patient may develop osteoradionecrosis of the jaw after head or neck radiation. The patient may have received the radiation well in the past, Miller adds.
Medicare requires that all of the following criteria are met and documented:
  • The patient received radiation (get dates, place of service, records)
  • X-ray, bone scan, or MRI is positive for osteoradionecrosis
  • The physician documented a diagnosis of osteoradionecrosis
  • HBO is an adjunct to an overall plan that includes surgery
Alternately, a patient may suffer a soft tissue injury as the result of radiation. Medicare requires that the patient:
  • Received radiation (get dates, place of service, records)
  • Has a diagnosis of proctitis, cystitis, enteritis, or fibrosis of skin as a result of radiation
Compromised flap/graft
Some patients with a skin flap or graft may also benefit from HBO therapy if the graft or flap is failing. “I like to look at this as a compromising flap or graft,” Miller says. “It is in the process of failing. It’s not already a failed flap or graft.”
Medicare requires that all criteria are met and documented:
  • Patient had an autologous flap/graft applied (Apligraf and Dermagraft are not allowed)
  • The graft is in the process of failing
  • The failed graft site is in need for prep before another one can be applied
Note that old dehisced wounds do not meet the criteria, Miller says.
Typically these patients are treated very quickly when the flap or graft starts to fail, Miller says. They typically undergo two HBO treatments each day for the first three days instead of the more normal one treatment per day.
Additionally, these patients may be treated initially as inpatients, she adds.
Hospital billing for HBO
Coders report HBO therapy services using HCPCS code C1300 (hyperbaric oxygen under pressure, full body chamber, per 30-minute interval) under revenue code 413 (hyperbaric oxygen therapy).
Typically, treatment lasts for 110 minutes: 10 minutes for the descent, 90 minutes at depth, and 10 minutes for the ascent, Miller says. This equates to four units of C1300. In order to round up the number of units, the time must be longer than 15 minutes more than the previous unit. For example, if a patient received 44 minutes of HBO therapy, coders can only report one unit. If the patient received 50 minutes of HBO therapy, coders can report two units.
In addition, coders can report an E/M code for wound management or a separately identifiable visit work before or after HBO, Miller says. Coders may also report debridement on the same day as HBO. Medicare expects debridement to be done weekly as medical necessity dictates.
Coders cannot separately report wound care dressing changes before or after unless the physician documents a separate and distinct E/M service.
E-mail your questions to Senior Managing Editor Michelle A. Leppert, CPC, at

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