Dive Deeper into HBO Therapy in Wound Care Centers

Dive Deeper into HBO Therapy in Wound Care Centers

Exact documentation criteria and limited diagnosis codes pose hyperbaric oxygen therapy coding challenges.

Dive Deep into HBO Therapy in Wound Care Centers” (April 2018, pages 42-44) provided detailed information on Medicare coverage indications, provider supervision/qualifications, documentation, and procedural coding requirements for the provision of hyperbaric oxygen therapy (HBOT) in the outpatient setting. The article also highlighted the scrutiny of this treatment modality by the Centers for Medicare & Medicaid Services (CMS) and the Office of Inspector General (OIG). In light of that ongoing scrutiny, and the recent distribution of an OIG report (see Resources for a link), now is a good time to dive even deeper into payer requirements for this service.

OIG Report Finds HBOT Therapy Unsupported

According to the OIG’s report on Feb. 2, 2018, “Medical records submitted for review did not support that the HBO therapy provided met the requirements in NCD 20.29.”

For healthcare providers and coding/billing personnel who have been on the HBOT “front line” for the past decade, the OIG report was no surprise. The National Coverage Determination (NCD) for HBOT contains vague language for many of the indications, and the diagnosis codes provided for coverage are restricted. From a diagnosis assignment perspective, several of the approved HBOT indications pose unique coding challenges due to exacting documentation criteria and limited diagnosis codes, which are the focus of this discussion.

Note: The term “provider” throughout this article means physician or non-physician practitioner.

Diagnosis Assignment Is Specific

HBOT treatments are an adjunctive therapy provided in a pressurized hyperbaric chamber located in most hospital-based outpatient departments (HOPD) that specialize in advanced wound care. CMS covers 15 indications for HBOT, which are outlined in the NCD. Several regional Medicare Administrative Contractors (MACs) have developed Local Coverage Determinations (LCD) defining the 15 indications more specifically through utilization and documentation requirements.

Per NCD 20.29, diagnosis codes designated to an HBOT indication trigger coverage for that indication only (see Table 1). For diagnosis assignment, documentation requirements vary for each indication. At a minimum, the following information must be present in the medical record (as defined in LCDs):

  • Initial assessment detailing a plan of care, therapy goals, and medical necessity (reason for using the particular treatment modality for patient’s condition)
  • Medical history and physical (H&P) that clearly substantiates the condition for which HBOT is recommended
  • Prior medical, surgical, or adjunctive therapies and outcomes, as appropriate
  • Documentation of the procedure (logs) including ascent time, descent time, and pressurization level, as well as provider attendance and supervision
  • Providers’ progress notes describing the physical findings, type(s) of treatment(s), number of treatments, the effect of treatment(s) received, and the progress level assessment made toward completing established therapy goals (how wound/condition is responding to the therapy)
  • Provider-to-provider communications or records of consultations, additional assessments, recommendations, or procedural reports

Continued HBOT without documented evidence of effectiveness does not meet the Medicare definition of medically necessary treatment. Thorough re-evaluation should be made at least every 30 days for documenting therapy response. Documentation to support effectiveness of the therapy must be made available upon request to the MAC.

Table 1 CMS-approved Indications for HBOT

*Source: CMS NCD 20.29, Oct. 1, 2017

Diagnosis/Indication ICD-10-CM Codes
Actinomycosis A42.0, A42.1, A42.2, A42.89, A42.9, A43.0, A43.1, A43.8, A43.9,

B47.1, B47.9,


Acute Carbon Monoxide Intoxication T58.01XA, T58.02XA, T58.03XA, T58.04XA, T58.11XA, T58.12XA, T58.13XA, T58.14XA, T58.2X1A, T58.2X2A, T58.2X3A, T58.2X4A, T58.8X1A, T58.8X2A, T58.8X3A, T58.8X4A, T58.91XA, T58.92XA, T58.93XA, T58.94XA
Acute Peripheral Arterial Insufficiency I74.2, I74.3, I74.5
Acute Traumatic Peripheral Ischemia S35.511A, S35.512A, S45.011A, S45.012A, S45.091A, S45.092A, S45.111A, S45.112A, S45.191A, S45.192A, S45.211A, S45.212A, S45.291A, S45.292A, S75.011A, S75.012A, S75.021A, S75.022A, S75.091A, S75.092A, S85.011A, S85.012A, S85.091A, S85.092A
Chronic Refractory Osteomyelitis M86.38, M86.39, M86.48, M86.49, M86.58, M86.59, M86.68, M86.69, M86.311, M86.312, M86.321, M86.322, M86.331, M86.332, M86.341, M86.342, M86.351, M86.352, M86.361, M86.362, M86.371, M86.372, M86.411, M86.412, M86.421, M86.422, M86.431, M86.432, M86.441, M86.442, M86.451, M86.452, M86.461, M86.462, M86.471, M86.472, M86.511, M86.512, M86.521, M86.522, M86.531, M86.532, M86.541, M86.542, M86.551, M86.552, M86.561, M86.562, M86.571, M86.572, M86.611, M86.612, M86.621, M86.622, M86.631, M86.632, M86.641, M86.642, M86.651, M86.652, M86.661, M86.662, M86.671, M86.672, M86.8X0, M86.8X1, M86.8X2, M86.8X3, M86.8X4, M86.8X5, M86.8X6, M86.8X7, M86.8X8
Crush Injuries S47.1XXA, S47.2XXA, S57.01XA, S57.02XA, S57.81XA, S57.82XA, S67.01XA, S67.02XA, S67.190A, S67.191A, S67.192A, S67.193A, S67.194A, S67.195A, S67.196A, S67.197A, S67.21XA, S67.22XA, S67.31XA, S67.32XA, S67.41XA, S67.42XA, S77.01XA, S77.02XA, S77.11XA, S77.12XA, S77.21XA, S77.22XA, S87.01XA, S87.02XA, S87.81XA, S87.82XA, S97.01XA, S97.02XA, S97.111A, S97.112A, S97.121A, S97.122A, S97.81XA, S97.82XA,

T87.0X1, T87.0X2, T87.1X1, T87.1X2, T87.2

Cyanide Poisoning T57.3X1A, T57.3X2A, T57.3X3A, T57.3X4A, T65.0X1A, T65.0X2A, T65.0X3A, T65.0X4A
Decompression Illness T70.29XA, T70.3XXA
Diabetic Wounds of the Lower Extremities E10.51, E10.52, E10.618, E10.620, E10.621, E10.622, E10.628, E10.65, E10.69

E11.51, E11.52, E11.618, E11.620, E11.621, E11.622, E11.628, E11.65, E11.69

E13.51, E13.52, E13.618, E13.620, E13.621, E13.622, E13.628

and (dual diagnosis)

I70.25, I70.231, I70.232, I70.233, I70.234, I70.235, I70.238, I70.241, I70.242, I70.243, I70.244, I70.245, I70.248, I70.331, I70.332, I70.333, I70.334, I70.335, I70.338, I70.341, I70.342, I70.343, I70.344, I70.345, I70.348, I70.431, I70.432, I70.433, I70.434, I70.435, I70.438, I70.441, I70.442, I70.443, I70.444, I70.445, I70.448, I70.531, I70.532, I70.533, I70.534, I70.535, I70.538, I70.541, I70.542, I70.543, I70.544, I70.545, I70.548, I70.631, I70.632, I70.633, I70.634, I70.635, I70.638, I70.641, I70.642, I70.643, I70.644, I70.645, I70.648, I70.731, I70.732, I70.733, I70.734, I70.735, I70.738, I70.741, I70.742, I70.743, I70.744, I70.745, I70.748,

L97.111, L97.112, L97.113, L97.114, L97.115, L97.116, L97.118, L97.121, L97.122, L97.123, L97.124, L97.125, L97.126, L97.128, L97.211, L97.212, L97.213, L97.214, L97.215, L97.216, L97.218, L97.221, L97.222, L97.223, L97.224, L97.225, L97.226, L97.228, L97.311, L97.312, L97.313, L97.314, L97.315, L97.316, L97.318, L97.321, L97.322, L97.323, L97.324, L97.325, L97.326, L97.328, L97.411, L97.412, L97.413, L97.414, L97.415, L97.416, L97.418, L97.421, L97.422, L97.423, L97.424, L97.425, L97.426, L97.428, L97.511, L97.512, L97.513, L97.514, L97.515, L97.516, L97.518, L97.521, L97.522, L97.523, L97.524, L97.525, L97.526, L97.528, L97.811, L97.812, L97.813, L97.814, L97.815, L97.816, L97.818, L97.821, L97.822, L97.823, L97.824, L97.825, L97.826, L97.828

Gas Embolism T79.0XXA, T80.0XXA
Gas Gangrene A48.0
Osteoradionecrosis M27.2, M27.8
Compromised Skin Grafts T86.820, T86.821, T86.822, T86.828
Progressive Necrotizing Infections M72.6
Soft Tissue Radionecrosis L59.8, N30.40, N30.41


The Undersea and Hyperbaric Medicine Society (UHMS) lists additional indications for HBOT. Some commercial payers may recognize these conditions, as well; however, Medicare does not recognize the following diagnoses for HBOT:

  • Exceptional Blood Loss Anemia D50.0, D62
  • Intracranial Abscess G06.0
  • Idiopathic Sudden Sensorineural Hearing Loss H90.5
  • Central Retinal Artery Occlusion H34.10, H34.11, H34.12, H34.13
  • Thermal Burns Numerous codes

Challenging Indications for Coders

Diabetic Wounds of the Lower Extremities (DWLE)

DWLE is the indication that receives the most attention from coders — most likely because of the dual diagnosis requirement and associated conditions. Per the aforementioned OIG report:

Specifically, the records did not clearly support that the patient’s foot ulcer was due to diabetes. In addition, the records documented that the patient had lower extremity vascular insufficiency. There was no evidence that this vascular insufficiency was treated. Wounds that are due to chronic vascular insufficiency are not eligible for HBO therapy. Furthermore, the wound consistently was noted in the medical record as being Wagner grade I. To be eligible for HBO therapy, diabetic wounds must be Wagner grade III or higher.

The most common issue  is the provider inadequately documenting the patient’s diabetes history (e.g., type and glucose control), and the relationship between the diabetes and wound(s). This directs coders to a more generic and non-payable diabetes/ulcer code (for DWLE).

In the ICD-10-CM Alphabetic Index, under “diabetes type,” you’ll see “with” immediately listed; and many terms/conditions are listed “with diabetes.” For example, Type 2 diabetes with foot ulcer directs you to assign diagnosis code E11.621 Type 2 diabetes mellitus with foot ulcer, which is one of the payable codes for this indication. Based on current coding conventions, the “with” is interpreted to mean “associated with or due to.” There is a presumed causal relationship between diabetes and those listed under “with.” This causal relationship exists even in the absence of provider documentation explicitly linking the conditions. Guidance was clarified in November 2017 by the American Hospital Association (AHA) in their Fourth Quarter Coding Clinic instructions for conditions listed with NEC (not elsewhere classified) codes. Payment is only allowed for specific diabetes and ulcer codes, and the provider must link the ulcer with the diabetic condition for NEC codes.

Payment may still be denied if the record is reviewed and the Wagner scale (grade 3 or greater) and 30-day time frame for wound care (and no measurable signs of healing) are not documented and coded, as such. The wound can be treated in the wound care center for 30 days and by another provider (or by a combination of both) prior to HBOT initiation. If the wound care/HBOT provider briefly summarizes the wound care given previously or includes notes from the referring provider into the center’s medical record, this meets the coverage requirements and allows coders to assign appropriate diagnosis codes.

Chronic Refractory Osteomyelitis (CRO)

CRO is an indication where documentation should define osteomyelitis as chronic and refractory. The U.S. National Center for Health Statistics (NCHS) defines a chronic condition as one lasting three or more months; although, there are more than several different interpretations of the time frames to define chronicity (ranging from three weeks to three months). CRO is further defined by NCD 20.29 and LCDs as “Unresponsive to conventional medical or surgical management.” HBOT should be an adjunctive therapy only after appropriate medical and surgical interventions have been documented. If these interventions are not clinically appropriate, documentation must clearly define why these options were ruled out before HBOT is an appropriate clinical progression.

LCDs define which interventions are appropriate (i.e., antibiotics, aspiration of the abscess, surgery and/or surgical debridements, immobilization of the affected extremity, etc.). Before beginning HBOT, the medical record should clearly demonstrate the presence of osteomyelitis through radiology or pathology (bone scan, X-ray, magnetic resonance imaging, and/or bone biopsy) reports. If the radiology results show acute osteomyelitis, and the record is coded as such, then the use of HBOT is not acceptable until it becomes chronic in nature.

Compromised Flaps/Grafts

Compromised flaps/grafts become a coding issue when the medical record does not reflect the description of the postoperative state of flap/graft failure (e.g., tissue mottling or necrosis), which justifies the medical necessity for HBOT. If possible, documentation should include an area description prior to flap/graft procedure (including location, measurements, grade, or state). Including a summary or the operative note indicating flap/graft creation is helpful, as well.

It’s also important to document the situation accurately when a patient presents with non-reversible vascular compromise, which progresses to an amputation as a result of the poor vascular status. If the resulting flap from that procedure “fails” by becoming ischemic or hypoxic (as demonstrated by documented signs/symptoms), the provider must document the underlying reason for the amputation; otherwise, coders may think the resulting flap compromise is due to “a complication of the amputation,” and obtain a different diagnosis code that’s not payable for HBOT.

In some instances, coders maintain that the words “flap” and “graft” do not mean the same thing, even though providers use these terms interchangeably. Historically, the term flap was found in most of the HBOT LCDs, but as many of those LCDs were retired, the word has disappeared. It’s not used in NCD 20.29. This is an important distinction you must address because the appropriate diagnosis code cannot be located by using “flap” as the key search word in some coding software or in the ICD-10-CM Alphabetic Index. The key search word is “skin graft” when attempting to reach the payable diagnosis code. If coding personnel at your hospital facility or provider practice are adamant that “flap” cannot be used as an alternate word to “graft,” then educate providers and staff accordingly.

Soft Tissue Radionecrosis (STRN) and Osteoradionecrosis (ORN)

STRN and ORN have common prerequisites for appropriate code assignment of either condition:

  • A documented history of radiation treatment to the region of the injury;
  • Terminating at least six months prior to onset of signs or symptoms; and/or
  • Planned surgical intervention at the site.

This may be accomplished by including the referring provider’s notes indicating they “ruled out” other conditions and provided a diagnosis based on the patient’s history of radiation treatments and current symptoms. If diagnostic results are not available, then the HBOT provider must confirm in the progress note there is radiation damage.

Equally important, the documentation should include a description of the ORN or STRN manifestations (e.g., decayed teeth, thickening of oral mucosa, recession of gingiva, pain, blood loss, tissue necrosis, infections, non-healing ulcerations, visible bone, etc.). Because the use of HBOT is one part of an overall care plan that also includes debridement or resection of nonviable tissue with antibiotic therapy, these interventions must be documented.

Code assignment becomes more challenging because there are only three codes listed for STRN:

L59.8      Other specified disorders of the skin and subcutaneous tissue related to radiation

N30.40   Irradiation cystitis without hematuria

N30.41   Irradiation cystitis with hematuria

Although L59.8 captures the coverage intent of the NCD for most soft tissue conditions, coding gets complicated due to the need for specificity when providers are documenting conditions such as radiation proctitis, colitis, or enteritis. According to the Novitas LCD (L35021), coverage for soft tissue injury due to radiation exists for “Beneficiaries suffering from soft tissue damage or bone necrosis present with disabling, progressive, painful tissue breakdown, bleeding, bowel or bladder dysfunction, wound dehiscence, infection, tissue loss and graft or flap loss.” But if a provider states that the patient has “radiation proctitis” (a soft tissue injury due to radiation), and fails to mention the soft tissue damage, you are forced to use K62.7 Radiation proctitis, alone. A similar situation is encountered with gastroenteritis and colitis due to radiation: They both lead to K52.0 Gastroenteritis and colitis due to radiation. Neither code is a payable diagnosis, which leads to billing issues and potential denials. This is why ongoing communication between providers and coding personnel is so important.

Auditing for Compliance and Provider Education

Auditing providers’ documentation and providing follow-up education are important measures for reducing compliance risks. A recent survey of more than 1,000 healthcare professionals by Healthicity  determined only 34 percent of organizations conduct formal documentation/coding audits on individual providers each year. Almost half (45 percent) of the respondents indicated they don’t have time to communicate their audit results back to the providers 100 percent of the time.

Errors identified in the audit process represent an opportunity to provide feedback for future process improvement, and it’s important to share the results with hospital administration, HOPD staff, and providers. Your hospital compliance department also may be interested.

The importance of education cannot be overemphasized. Even Medicare is getting on board with their latest “Targeted Probe and Educate” program, which focuses on providers (and hospitals) with high denial rates and/or unusual billing practices (e.g., billing a high-level E/M for every visit). Once identified, CMS performs audits and provides one-on-one education sessions to assist the provider in correcting the issues.

Note: One of the most common claim errors identified by this program is that documentation does not meet medical necessity.

Michael Crouch, CHT, CPC, is founder of C+ Consulting, LLC, a healthcare consulting firm focusing on revenue integrity and hyperbaric medicine training for outpatient wound centers. He has more than 25 years’ experience in the healthcare industry, including former vice president of reimbursement and corporate hyperbaric safety officer for a multi-center management company. Crouch is former chair of the UHMS Associates. and is a member of the San Antonio, Texas, local chapter.


OIG, Audit A-01-15-00515: https://oig.hhs.gov/oas/reports/region1/11500515.asp

CDC, NCHS: www.cdc.gov/nchs/index.htm

CMS, NCD Manual, IOM Pub. 100-3, chapter 20, section 20.29 (Rev. 203, effective April 3, 2017, Implementation: Dec. 18, 2017: www.cms.gov/Regulations-and-Guidance/Guidance/Manuals/Internet-Only-Manuals-IOMs.html

Novitas Solutions Inc., LCD L35021 (Rev. 04-01-18):

ICD-10-CM Official Guidelines for Coding and Reporting (FY 2018, 10-01-17 – 09-30-18)

AHA, Coding Clinic for ICD-10-CM/PCS, Fourth Quarter 2017, p. 100

Leave a Reply

Your email address will not be published. Required fields are marked *