Q&A: Sepsis criteria follow-up

CDI Blog - Volume 12, Issue 38

Q: I was reading the Q&A from CDI Strategies, , and I wanted to check whether I’m misinterpreting it. It seems that you are insinuating that vasopressors or lactate level >2 are either/or criteria for septic shock according to sepsis-3, when really this statement says “and.” Here’s what you wrote in CDI Strategies:

If you look closely, there are more criteria for septic shock in sepsis-3 than just the use of vasopressor to maintain a MAP >65. According to the sepsis-3 definition:

Patients with septic shock can be clinically identified by a vasopressor requirement to maintain a mean arterial pressure of 65 mm Hg or greater and serum lactate level greater than 2 mmol/L (>18 mg/dL) in the absence of hypovolemia.

Note the “or” in “or greater and serum lactate level greater than 2 mmol/L (>18 mg/dL) in the absence of hypovolemia.” This is especially helpful in identifying patients with positive cardiac compensatory mechanisms that would be otherwise missed using blood pressure (BP) alone.

Also, keep in mind the baseline leveling. My wife barely reads a 90/50 on a healthy day, so a BP of 87/45 may not be especially concerning.

Am I interpreting this correctly?

A: What you are looking at is two axis: the hypotension alone being the cardiovascular compromise and the lactate level being an indicator of cellular compromise. 

There were two criticisms of using lactate:

  1. Lactate adds complexity and cost and cannot be used at the bedside
  2. Lactate may be elevated in conditions other than sepsis/septic shock. 

The issue is that you may not always be able to get both. Take a look at this article from the Journal of the American Medical Association (JAMA): 

In settings in which lactate measurement is not available, the use of a working diagnosis of septic shock using hypotension and other criteria consistent with tissue hypoperfusion (e.g., delayed capillary refill) may be necessary.

You should note above that hyperlactemia is clearly a better predictor of mortality than hypotension alone, and yet the sepsis-3 paper acknowledges that hypotension alone may be used. This begs the question as to why you wouldn’t also look at elevated lactates independently since they are better predictors of mortality than hypotension alone and hypotension alone may be used in certain circumstances (more on the scientific study of that below).

It is noteworthy that in sepsis-3, elevations of lactate did not significantly improve predictive validity for “vanilla” sepsis without shock over the standard six sequential organ failure assessment (SOFA) data points, but the paper does acknowledge the elevation may “help identify patients at intermediate risk.” So, the data would still be valid as criteria even though not part of the SOFA data set.

The Surviving Sepsis Campaign suggests “guiding resuscitation to normalize lactate in patients with elevated lactate levels as a marker of tissue hypoperfusion,” although it’s flagged as a “weak” recommendation because certain drugs will also increase lactate levels in the blood and lactate may even be a positive compensatory mechanism in a shock patient while still being a predictive indicator in the same way that simple tachycardia is a positive compensatory mechanism (to a point) while also being a predictive indicator.

The bits about looking at lactate as an independent variable come from the medical literature:

Be warned that auditors are likely to take the same overly narrow and clinically incorrect interpretation that “and” means “one or the other” as it will give them greater grounds to deny reported cases of sepsis/septic shock. Just because auditors apply an overly strict interpretation, hardly constitutes confirmation that their point of view is the clinically correct one. There is plenty of clinical literature that states otherwise. I go where the science points, not where the auditors attempt to push us.

Editor’s note: Allen Frady, RN, BSN, CCDS, CCS, CRC, CDI education specialist for HCPro in Middleton, Massachusetts, answered this question. Contact him at AFrady@hcpro.com. For information regarding CDI Boot Camps, click here.

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