Q&A: Coding acute hypoxic and acute hypercapnic respiratory failure

Q: When the physician documents that the patient is acute hypoxic and acute hypercapnic, should we code both of these diagnoses?

A: The first step to answering your question would be to look up respiratory failure in the Alphabetic Index. When you do, you find that under the main bolded term of “Failure, failed” you will find, (when you scroll down the page) respiration, respiratory code J96.90 and when looking further down the page you find both options under the word acute J96.00 with hypercapnia code J96.02 and hypoxia code J96.01. This tells us that both can be coded.

Now, when you turn to the DRG Expert you will find both of these codes bring us to the same DRG which is found in MDC 4 Diseases and Disorders of the Respiratory System. You may see the code J96* Respiratory failure, not elsewhere classified (NEC). The asterisk lets us know that there is a range of codes that would be found under this one code, but because this is not a code book, not all are listed individually.

The second step in the process would be to make sure that the documentation in the medical record of these two diagnoses is by a hands-on, treating provider, and conflicting information between this provider and the patient’s attending provider doesn’t muddy the waters here. (Per CMS, the attending provider is the physician who provides the discharge summary.) If both are appropriately documented and clinically supported in the documentation, then the answer would be yes, both could be coded.

Finally, let’s take a look at the definition of respiratory failure. It is defined as abnormal arterial oxygenation and/or carbon dioxide accumulation, signs and symptoms can range from shortness of breath, dyspnea, tachycardia, respiratory rate greater than 20 cyanosis or labored breathing, just to name a few.

The diagnostic criteria for hypoxemia would be a partial pressure of oxygen (pO2) level less than 60 millimeters of mercury (mmHg) (oxygen saturation of less than 91%) on room air, or pO2/fraction of inspired oxygen (P/F) ratio (pO2/FIO2) less than 300 (not used for patients with chronic respiratory failure on continuous home oxygen) or 10 mmHg increase in baseline pO2 (if known baseline, this is why baseline information on patients if available is so important).

Hypercapnic diagnostic criteria would be pCO2 >50 mmHg with pH <7.35, or 10 mmHg increase in baseline pCO2 (again if known). Although not required, you can see why arterial blood gas results can be extremely helpful when dealing with the differentiation of hypoxemic versus hypercapnic respiratory failure.

Editor’s Note: Sharme Brodie RN, CCDS, CDI education specialist and CDI Boot Camp instructor for HCPro in Middleton, Massachusetts, answered this question. For information, contact her at sbrodie@hcpro.com. For information regarding CDI Boot Camps offered by HCPro, visit www.hcprobootcamps.com/courses/10040/overview.