Early Lactate Tests Impactful, But Often Not Performed With Sepsis

Early lactate measurements appear to improve results for patients with sepsis, but initial and repeat serum lactate levels are frequently not drawn in the recommended six-hour window, according to a study published online May 24 in the journal CHEST. The authors say that delays in lactate measurements for patients with initial abnormal values are associated with progressive increases in mortality.

In 2015 the Centers for Medicare & Medicaid Services introduced the Severe Sepsis and Septic Shock Early Management Bundle (SEP-1) to improve timely diagnosis and management of sepsis. The bundle requires providers to measure serum lactate, obtain blood cultures, and initiate antibiotics within a specified time window (An initial serum lactate level must be drawn between six hours before and three hours after severe sepsis presentation, followed by a repeat measurement within six hours of presentation if the initial value is elevated.) But, inclusion of serum lactate measurement proved to be controversial among sepsis experts.

Researchers from the University of Chicago sought to understand the impact of the bundle of recommendations on patients, so they retrospectively applied apply the SEP-1 definitions (two systemic inflammatory response syndrome criteria, display at least one new organ dysfunction, and documentation of suspicion of infection) to all adults admitted to the University of Chicago (n=149,6000) from November 2008 to January 2016. Time to lactate draw, antibiotic and IV fluid administration, and in-hospital mortality were evaluated.

Based on the 5,762 patients meeting all three SEP-1 criteria, the researchers found that overall, 60 percent of patients had an initial lactate drawn within the SEP-1-specified time, but there was variance by patient location. The mandated window was met only 32 percent of the time on the ward versus 55 percent of the time in the ICU and 79 percent of the time in the emergency department.

“Sepsis bundles have often focused on emergency department patients, but our study demonstrates that a large number of patients become newly septic on the wards and have higher mortality than those who initially meet criteria in the emergency department. This is an important population of patients in which to effectively and quickly identify and treat sepsis.

Delayed lactates (lactate samples drawn from three to 24 hours after the time of suspicion of infection) occurred for 14 percent of the patients meeting severe sepsis criteria. More than one-quarter of patients with sepsis (26 percent) did not have a lactate drawn within 24 hours of suspicion of infection.

Patients with delayed lactate measurements demonstrated the highest in-hospital mortality (29 percent) and had increased time to antibiotic administration. Patients with abnormal initial lactates (> 2.0 mmol/L) showed a significant increase in the odds of death for each hour of delay in lactate measurement. Lastly, length of stay was longest for patients who never had lactates drawn (median, 18 days), followed by those with delayed lactates (median, 15 days), versus 11 days for patients who had a lactate sample drawn in the SEP-1 window.

“Systematic early lactate measurement for all patients with sepsis will lead to a significant increase in lactate draws that may prompt more rapid physician intervention for patients with abnormal initial values,” write the authors led by Xuan Han, M.D.

Takeaway: This study adds evidence that systematic early lactate measurements in suspected patients with sepsis can positively affect outcomes, including time to intervention, mortality, and length of stay.