Coding Tip

Postop respiratory failure: The never-ending query

By Donielle Bailey, RHIA, Norwood Senior Auditor

We have all experienced the frustration of coding a complex or detailed elective operative report only to become ensnared in a postop progress note respiratory battle. Physicians provide their clinical assessment of the patient’s postop respiratory condition with documentation that includes, “intubated for airway protection,” “respiratory distress,” “intubated for airway protection and respiratory failure,” escalating to “acute postoperative respiratory failure.”

Acute respiratory failure unrelated to surgery can positively affect a patient’s MS-DRG, Severity of Illness (SOI), and Risk of Mortality (ROM) scoring. Postoperative (acute, or acute on chronic) respiratory failure can result in a Patient Safety Indicator (PSI 11) that can impact the hospital’s reimbursement and the quality-of-care scores for both the hospital and the surgeon. In addition, acute and postoperative respiratory failure are targets for recovery audit contractors.

Providers often use documentation of postoperative respiratory failure to justify the higher level of care needed to manage their patients. However, the dichotomy associated with this condition emphasizes the need for CDI and coding professionals to ensure the correct documentation and clinical evidence to support the accurate code assignment.

Speaking of The Never Ending Story (any fans out there?), coders and CDI professionals feel like they are trying to stop The Nothing with never-ending queries of this condition.

To ensure proper documentation, we must first understand that “postoperative” has two meanings. These include:


  1. The condition occurred after a recent surgical procedure


  1. The condition is “related to” or “a complication” of the recent surgical procedure


The FY2023 Official Guidelines for Coding and Reporting (OCG), section I.B.16 states:

Code assignment is based on the provider’s documentation of the relationship between the condition and the care or procedureunless otherwise instructed by the classification….There must be a cause-and-effect relationship between the care provided and the condition, and the documentation must support that the condition is clinically significant. It is not necessary for the provider to explicitly document the term “complication.”

When the documentation states “postoperative respiratory failure,” a cause-and-effect relationship is not clearly communicated due to the double meaning of “postoperative.” Coders and CDI professionals should query the provider to determine if the condition occurred in the postoperative period, is a “result of,” or is an “unexpected outcome” of the recent surgical procedure.

Secondly, it is vital to confirm the diagnosis of respiratory failure clinically. Clinical evidence must show that the patient has an acute respiratory dysfunction requiring treatment using measures that are not routine or planned. Clinically, the provider should note two of the following three criteria to demonstrate acute respiratory dysfunction.

  • pO2 less than 60 mm Hg (hypoxemia)
  • pCO2 greater than 55 mm Hg (hypercapnia) with pH less than 7.35
  • Signs or symptoms of respiratory distress including dyspnea, tachypnea (respirations >20), wheezing, decreased respirations (<10), labored breathing, accessory muscle use, or cyanosis.

While arterial blood gas (ABG) and pulse oximetry are commonly used to diagnose respiratory failure, a patient with documented signs and symptoms of respiratory distress and a room air oxygen saturation of less than or equal to 90% can also meet criteria. Venous blood gases can diagnose hypercapnic respiratory failure but are not considered accurate enough for diagnosing hypoxic respiratory failure.

In the absence of clinical support, query the provider for the clinical indicators to support the condition.

To validate that the treatment measures were not planned or routine, verify the treatment plan in elective cases. A patient with a surgical plan that includes 24-48 hours of ventilator time postop would not meet this unplanned criterion. Patients re-intubated or placed on non-mechanical ventilation post-procedure may be in respiratory failure.

If the documentation is unclear or the condition is unsupported, query the provider for clarification.

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