Query Tip: Identifying Opportunities To Query For Acute Respiratory Failure

Acute respiratory failure occurs when the lungs cannot effectively perform their primary function of gas exchange, which is the ability of the lungs to transfer oxygen into the blood and remove carbon dioxide from the blood. This sudden inability of the lungs to adequately oxygenate the blood (hypoxemia) or remove carbon dioxide from the blood (hypercapnia) leads to a life-threatening condition. Acute respiratory failure can be caused by various respiratory, cardiovascular, or systemic diseases in previously healthy individuals. Acute respiratory failure accounts for 25-40% of ICU admissions and carries a mortality rate of 30% or more.

Acute respiratory failure (ARF) is a medical emergency requiring immediate intervention to support breathing and address the underlying cause. The presence of ARF increases resource utilization and costs incurred by the hospital or facility by lengthening the patient’s stay, requiring use of oxygen or ventilation devices, and the medications given.

Ensuring complete and accurate code assignment is essential to covering the costs incurred from treating acute respiratory failure. Failure to report the presence of ARF may mean the incorrect DRG is assigned and does not reflect the patient’s severity of illness and resources required for treatment of the patient.

Recognizing opportunities to query for ARF requires understanding the signs and symptoms of acute respiratory failure and the clinical criteria/tests involved for diagnosing ARF and its treatment.

How Does Respiration Work?

Upon inhalation, oxygen molecules in the air we breathe travel to the lungs and arrive at the alveoli (small air sacs within the lungs). Blood traveling around the alveoli picks up oxygen molecules for transport to the tissues of organs and muscles and releases carbon dioxide (waste product) into the alveoli that it has collected while traveling throughout the body. Carbon dioxide is released from the lungs during exhalation.

Image courtesy of Wikimedia Commons.

What are the Types of Respiratory Failure?

Hypoxemic Respiratory Failure: The primary issue is low oxygen levels in the blood (hypoxemia), which can be due to numerous factors like pneumonia, pulmonary embolism, or fluid buildup in the lungs. 

Hypercapnic Respiratory Failure: The primary issue is elevated carbon dioxide levels in the blood (hypercapnia), often caused by conditions that impair ventilation, such as COPD or neuromuscular diseases. 

What are the Symptoms of Acute Respiratory Failure?

There are many symptoms that indicate a diagnosis of acute respiratory failure, including:

• Shortness of breath or feeling like you cannot get enough air (dyspnea)
• Accessory muscle use
• Rapid breathing (tachypnea)
• Extreme tiredness (fatigue)
• Fast heart rate (feeling like your heart’s racing) or heart palpitations
• Spitting or coughing blood or bloody mucus (hemoptysis)
• Excessive sweating
• Restlessness
• Pale skin
• Bluish skin, lips, or nails (cyanosis)
• Headaches
• Blurred vision
• Agitation, confusion or being unable to think straight
• Behavioral changes, not acting like yourself

What Causes Acute Respiratory Failure?

Acute respiratory failure generally results from one of two causes:

• Diseases affecting the airways: such as asthma and chronic obstructive pulmonary disease (COPD), where there is an increase in airway resistance resulting in expiratory flow limitation.
• Diseases affecting the alveoli: such as pneumonia, acute cardiogenic pulmonary edema, influenza and ARDS, where there is a decrease in lung compliance (the ease with which the lungs can expand and contract) which can lead to the need for increased ventilatory pressures which may cause injury of the delicate tissues of the lung.

What are the Diagnostic Criteria?

A primary clinical criterion supporting a diagnosis of acute respiratory failure is a measurement of how well a patient’s blood is oxygenated. Methods for measuring oxygenation include arterial blood gases (ABGs), venous blood gases (VBGs) and pulse oximetry. What are the Diagnostic Criteria? A primary clinical criterion supporting a diagnosis of acute respiratory failure is a measurement of how well a patient’s blood is oxygenated. Methods for measuring oxygenation include arterial blood gases (ABGs), venous blood gases (VBGs) and pulse oximetry.

Diagnostic Criteria for Acute Hypoxemic Respiratory Failure

• PaO2 < 60 mmHg on room air measured by ABG, or
• SpO2 < 91% on room air measured by pulse oximetry, or
• P/F ratio < 300 on oxygen

Diagnostic Criteria for Acute Hypercapnic Respiratory Failure (Acute Respiratory Acidosis)

• PaCO2 > 50 mmHg with pH < 7.35 (ABG)
• pCO2 > 55 mmHg with pH < 7.33 (VBG)

NOTE: A diagnosis of acute respiratory failure must be supported by clinical signs and symptoms and treatment. A diagnostic test result alone is not definitive for respiratory failure.

How is Acute Respiratory Failure Treated?

Supplemental oxygen is the primary treatment for respiratory failure. Use of assistive ventilatory devices such as BiPAP or mechanical ventilation is not required to establish the diagnosis.

Treatment options include:

• Oxygen therapy- High flow oxygen is not a requirement to treat acute hypoxic respiratory failure- conventional oxygenation with simple face mask, non-rebreathing mask or nasal cannula are adequate treatment.
• Noninvasive positive pressure ventilation (NPPV) (CPAP) (BiPAP)
• Bag mask ventilation
• Mechanical ventilator support
• Tracheostomy
• Medication to open airways or relieve fluid build-up

Coding Challenges

The need for comprehensive documentation and review of clinical information makes coding for acute respiratory failure challenging. Coders must be able to differentiate between acute and chronic failure, identify the specific type of failure (e.g., hypoxia, hypercapnia), and understand the impact of underlying conditions on the overall respiratory state. 

Clear and detailed documentation from providers is essential for accurate code assignment. Coders may need to query providers for clarification on ambiguous or unclear documentation. 

How do you Know When to Query for Acute Respiratory Failure?

A query for the type and acuity of respiratory failure is appropriate when the documentation supports:

• The patient is experiencing signs and symptoms of respiratory failure
• Documentation includes clinical indicators of acute respiratory failure
• Treatment for acute respiratory failure is provided

A clinical validation query is appropriate when there is documentation of acute respiratory failure, but the patient is not experiencing signs/symptoms, or the presence of clinical criteria has not been established.

References

• Cleveland Clinic Health Library Respiratory Failure
• NIH National Library of Medicine Acute Respiratory Failure
• Arterial Versus Venous Blood Gas Analysis Comparisons, Appropriateness, and Alternatives in Different Acid/Base Clinical Settings: A Systematic Review
• Diagnosis and Management of Acute Respiratory Failure
• Pinson & Tang CDI Pocket Guide
• Pinson & Tang Query Templates

For more than 30 years, HIA has been the leading provider of compliance audits, coding support services and clinical documentation audit services for hospitals, ambulatory surgery centers, physician groups and other healthcare entities. HIA offers PRN support as well as total outsource support.

The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.