Postprocedural respiratory failure

How to properly make and document the diagnosis of respiratory failure following surgery.

The diagnosis of respiratory failure following surgery (post-op or postprocedural respiratory failure) has significant revenue, regulatory, and quality of care implications. It often results in a huge payment increase to the hospital. If improperly diagnosed without firm clinical grounds, it may become the basis for regulatory audits, sanctions, or penalties.

Respiratory failure is caused by either impaired alveolar gas exchange or inadequate ventilation. There are two types, hypoxemic and hypercapnic, and patients commonly have a combination of both. Patients who do not have an intrinsic impairment of gas exchange or ventilation do not have respiratory failure, including those patients who require routine post-op mechanical ventilation for an expected period.

The clinical states of oxygenation are shown in Table 1. Hypoxemic respiratory failure is defined as either an arterial partial pressure (PaO2) less than 60 mm Hg breathing room air, or a PaO2/FiO2 ratio less than 300 while on supplemental oxygen. Acute hypercapnic respiratory failure is defined as a significantly elevated arterial partial pressure (PaCO2) to 50 mm Hg or more and a pH less than 7.35.

With the advent of ICD-10-CM, there have been some significant changes in the quality reporting of respiratory difficulty following trauma and surgery. Table 2 shows the codes used for these post-op problems. Any or all of them are potentially considered a serious post-op complication by a variety of systems that analyze quality and other performance measures.

Fortunately, the CMS patient safety indicator 90 (PSI-90) only includes ICD-10-CM codes J95821 and J95822, which are assigned whenever “respiratory failure” is documented postoperatively. However, if acute respiratory failure actually occurred preoperatively and persisted postoperatively or is specifically attributed primarily to a pre-existing medical condition, such as heart failure or severe chronic obstructive pulmonary disease, rather than a direct consequence of the procedure, different codes may be assigned: J96.00-J96.02 or J96.20-J96.22 for respiratory failure related to other medical conditions. These codes are not included in PSI-90.

Photo by Thinkstock
Photo by Thinkstock.

Healthgrades does not use the post-op codes to identify respiratory failure as an inpatient complication but rather considers any coding of J96.00-J96.02 and J96.20-J96.22 that was not present on admission to be a significant complication of care.

Use of the term “pulmonary insufficiency” postoperatively does not indicate a postoperative complication for PSI-90 or Healthgrades criteria. However, other quality analytic systems may have different inclusion criteria. In any case, pulmonary insufficiency seems to be a nebulous, undefined condition, whereas respiratory failure is well defined. Clinicians should not be documenting postoperative pulmonary insufficiency in cases where the criteria for respiratory failure are clearly met with the intent of improperly avoiding what should correctly be identified as a complication of care.

For many years, the documentation of post-op respiratory failure or pulmonary insufficiency in patients who require a routine period of mechanical ventilation, even when no pulmonary problem or complication is present, has been a common practice to identify a condition that would support billing of critical care services. However, CMS and other payers frown upon documentation of a condition that a patient really doesn't have, meaning that this traditional practice raises compliance risks. Perhaps a diagnosis of respiratory insufficiency or insufficient respiration (both coded R06.89) without reference to “acute” would be a reasonable alternative in these circumstances.

Acute respiratory distress syndrome (ARDS), also once known as acute lung injury, is a specific pathologic condition having certain clinical characteristics causing acute severe respiratory failure. It is a type of acute diffuse inflammatory lung injury, leading to increased pulmonary vascular permeability, increased lung weight, and loss of aerated lung tissue. Typical causes of ARDS are sepsis, aspiration, prolonged shock, and multiple, severe trauma. Other potential causes include cardiopulmonary bypass, difficult prolonged surgery, multiple transfusions, fat embolism, and fulminant pancreatitis.

ARDS is defined as the acute onset of hypoxemia (PaO2/FiO2 <300) within one week of a known clinical insult to the lungs or onset of respiratory symptoms, with bilateral infiltrates consistent with pulmonary edema on imaging, not fully explained by heart failure or fluid overload. To fulfill the definition, the PaO2/FiO2 must be determined while the patient is being treated with positive end-expiratory pressure or continuous positive airway pressure with at least 5 cm of H2O either invasively (e.g. via an endotracheal tube) or noninvasively. Depending on the degree of hypoxemia, ARDS is classified as mild, moderate, or severe.

ICD-10-CM code J80 is used for ARDS and should not be assigned for any condition that is not documented as ARDS. Since ARDS is always associated with respiratory failure, the separate coding of acute respiratory failure is not permitted. ICD-10-CM does not provide codes to specify the severity of ARDS and does not link ARDS to any postprocedural complication code.

In summary, acute respiratory failure following surgery has significant revenue, regulatory, and quality of care implications. It should only be diagnosed and coded when the clinical criteria for acute respiratory failure are met. A correct diagnosis of ARDS should be made when criteria are met for which code ICD-10-CM code J80 is assigned without a code for respiratory failure.

Pulmonary insufficiency is a vague, nonspecific, undefined term that would be difficult to substantiate as a valid diagnosis and should not be used when the patient has respiratory failure or for post-op patients with no pulmonary disorder making a routine recovery on mechanical ventilation for an expected period of time. A diagnosis of respiratory insufficiency or insufficient respiration (both coded R06.89) without reference to “acute” might be a reasonable approach in these circumstances.