Note from the Instructor: Sepsis clinical indicators, competing etiologies—A critical thinking exercise

by Dawn Valdez, RN, LNC, CDIP, CCDS

Identifying sepsis is a complex process that takes more thought than checking off clinical indicators from a list regardless of what criteria is used to qualify the diagnosis. It takes critical thinking and oftentimes, collaboration with treating physicians to understand the intricate cellular processes involved in the sepsis manifestation and how these intracellular processes play out in a patient’s clinical presentation. In my experience reviewing medical records, one thing I often discovered were the clinical indicators used to validate sepsis also had other possible etiologies that could be equally responsible for the clinical indicator(s) that were present. These are known as “competing diagnoses” or “competing etiologies” because either condition could be responsible for the identified clinical indicators.

For example, if a facility continues to utilize Sepsis-2 criteria, an elevated heart rate above 90 is one criterion. But what if the patient also has an episode of atrial fibrillation (a-fib) rapid ventricular rate (RVR) at the same time? Does that weaken the validity of sepsis? The answer will depend on the other factors at play and how many strong clinical indicators are present that support the sepsis diagnosis .

In regard to fever, most of us have likely heard that fever contributes to tachycardia just as hypothermia is known to induce bradycardia. Under Sepsis-2 criteria, a CDI specialist should not accept two clinical indicators based only on vital signs. Using vital signs as the only clinical indicators for sepsis will not provide enough support for its presence; we must understand the reason why. Inquiring as to why, is how we apply critical thinking to our case reviews.

Let’s look at leukocytosis. Many patients that are sick with an infection are also dehydrated. Can dehydration contribute to a falsely elevated white blood count? The answer is yes it can as dehydration contributes to hemoconcentration of blood plasma. If labs are drawn prior to IV fluid administration (and antibiotics), hemoconcentration can demonstrate an elevated white blood count, falsely supporting the presence of leukocytosis.

To validate leukocytosis in a dehydrated patient, evaluate all cellular lines in the complete blood count (CBC) differential to determine if they demonstrate consistent elevation. It is rare to see all cellular lines (neutrophils, lymphocytes, eosinophils, basophils, and monocytes) elevated as a result of infection. If all cellular lines are elevated, it is likely that hemoconcentration has contributed to the apparent elevation of the white blood cell count.

When validating sepsis during the CDI review process, we should also consider if drug induced leukocytosis is present. Corticosteroids such as Solu Medrol and Prednisone, inhaled beta agonists such as Albuterol or Xopenex and lithium are examples of drug induced leukocytosis.

Other factors that may contribute to leukocytosis include recent surgery, inflammatory diseases such as rheumatoid arthritis or lupus, hypoxia with tissue damage, diabetic ketoacidosis (DKA)/diabetic hyperglycemic hyperosmolar syndrome, splenectomy, certain types of leukemia, trauma, emotional stress, strenuous exercise, and amphetamine and/or cocaine use.

When examining the CBC differential, the percentage of bands can provide an indication of the length of time an infection may have been present.

Bands are immature white blood cells released by the bone marrow into the circulation. This occurrence is an indication that the immune system is losing the war and is implementing a draft of immature cells (soldiers) to assist in the battle. Additionally, the band level is directly proportionate to how many immature cells are being released. The higher the band count, the more information this tells the CDI specialist about the level of infection and the body’s response. A band count greater than 10% is a Sepsis-2 indicator.

When evaluating bands, one must consider the patient’s medical history. Cancer patients on chemotherapy or radiation therapy, HIV patients, or other immunocompromised patients will typically not have a normal response to infection and the band count may not have the same indications that it does in a person with a normal immune response. Additionally, the CDI specialist must evaluate if the patient has been prescribed antibiotics during the localized infection.

Trending the neutrophil count aids the CDI specialist in understanding at what point in the disease process the infection likely began. This may assist a CDI specialist in supporting the present on admission status of sepsis. For example, if a patient without a pre-existing history of immune disease demonstrates a neutrophil band count of 23 on admission, it is a strong indication that the infection has been present prior to admission.

Lactic acid is an end result of the Kreb’s Cycle in the breakdown of glucose (glycolysis). Hyperlactatemia represents elevated lactic acid levels and when the PH becomes affected (lower than 7.35), lactic acidosis occurs. A few examples of factors that can influence or elevate a lactic acid level are medications such as metformin, linezolid, IV epinephrine, certain inhaled beta agonists (i.e., Albuterol), acetaminophen, cancer, DKA, non-compliant diabetes (chronically elevated A1C levels), chronic alcoholism, and tissue hypoxia.

The C-reactive protein (CRP) level is often ordered when sepsis is suspected as this protein is a known indicator for the presence of bacterial infections. But the patient’s history must also be considered in its interpretation. If the patient also has lupus, rheumatoid arthritis, Crohn’s disease, or colitis for example, this lab test may be misinterpreted.

So, do competing etiologies weaken the clinical indicators used to validate sepsis? Yes, they can and often do! Competing etiologies weaken the validity of sepsis, especially in circumstances where there are few clinical indicators to support it. Compliant CDI practice requires that competing etiologies should be outlined in a query, so the provider has all of the facts and can respond accordingly.

Clinical validation of sepsis can assist with denial prevention and works best when applied concurrently versus retrospectively. The role of validating a sepsis case begins with analyzing the initial presentation and gathering clinical indicators which could include normal values in addition to abnormal values.

Lastly, although it is not our responsibility to formulate a diagnosis, it is necessary to understand the potential indication of clinical indicators in addition to analyzing the patients presenting symptoms, medical history (including the severity of any comorbid conditions), competing etiologies, and overall immune function in order to evaluate the need for a clinical validation query.

Knowing that sepsis is frequently challenged, and differing criteria are used, the CDI specialist should proactively consider clinical validation in every sepsis review. One should consider not only the organizational approved diagnostic criteria, but the unique patient presentation, co-morbid conditions, competing etiologies, medication history and trending lab values. Our attention to detail, well informed query practice, and the resulting strong documentation can serve to prevent unnecessary sepsis denials.

Editor’s Note: Valdez is a CDI education specialist and CDI Boot Camp instructor for HCPro in Middleton, Massachusetts. For information, contact her at dvaldez@hcpro.com. For information regarding CDI Boot Camps, click here.