Q&A: Calculations to support clinical indicators in queries

Q: Does your team include calculations to support clinical indicators in your queries? Do your CDI specialists calculate P/F ratio and include the calculation in their query addressing respiratory failure? Do your CDI specialists calculate the corrected sodium level for pseudohyponatremia, and include it in the query?

Response #1: Our CDI team does calculate the P/F ratio for respiratory failure with the cited clinical indicators also included in the query.

There’s a post on the ACDIS website that addresses pseudohyponatremia specifically that may be helpful to you too. Additionally, Coding Clinic, first quarter 2020, describes pseudohyponatremia as an abnormal lab finding inherent to another underlying condition. As such, pseudohyponatremia cannot be coded, and coding efforts should focus on identifying the inciting cause.

Response #2: We do include a CDI-calculated P/F ratio, as well as a CDI-calculated KDIGO score when appropriate.

We do not, however, calculate the corrected sodium level for pseudohyponatremia, but I will have to look into this. I do note that if there has been a correction to the sodium, our physicians mention this, but makes me think we should be looking deeper at this.

Response #3: We have not made calculating the P/F ratio a requirement for respiratory failure queries, but many professionals on our CDI team do include the calculation or the indicators so that the provider may calculate the P/F ratio.

The staff do have a calculator resource to use for pseudohyponatremia queries, but we have not been putting the calculation in. It would be a good idea—it would be nice to have it embedded in a query template!

Response #4: We don’t type out the formula for P/F ratio, but we currently include something like “5/20 1300: SpO2 91% on 4L O2 = 166.7 mmHg pf ratio (Calculated by CDI).”

With pseudohyponatremia, we have a similar process and include something like: “5/20 1300: Sodium 124 and Glucose 350 = Corrected Sodium ** (Calculated by CDI)”

Response #5: Our CDI specialists do the calculations for both P/F ratio and corrected sodium to help inform their decision regarding appropriateness of the query, but they do not include the calculations in the query.  We also include a link to the calculators in the query for the providers’ convenience.

Editor’s note: This question was answered by members of the ACDIS CDI Leadership Council. For the purposes of this article, all Council member answers have been deidentified.