Written by Millie Cossé
Don’t hang your hat on lactate clearance to assess therapeutic response to resuscitation in sepsis; there are too many confounders, and initial clearance does not necessarily project clinical course.
Just another lab to trend
This study included 4,775 patients with clinical suspicion of infection who had 4 days of consecutive antibiotics and multiple serum lactate measurements. Authors examined the predictive value of lactate clearance (defined as a 10% drop in lactate in 2 to 12 hours) on 90-day hospital mortality rates. They found that patients who met the lactate clearance threshold had a lower 90-day hospital mortality rate than those who did not (15.9% vs 21.8%); however, the lactate clearance group had fewer comorbidities associated with poor lactate clearance. Specifically, cirrhosis has a 10.6% increased average marginal effect on absolute mortality. Given that lactate is primarily cleared by the liver, this is a huge confounder. A 24-hour change in peak lactate had better predictive power but is not useful for guiding initial resuscitation.
How will this change my practice?
The Surviving Sepsis campaign recommends guiding resuscitation to decrease serum lactate levels, though they acknowledge a low quality of evidence to support this recommendation. It is important to remember that the initial lactate trend is most likely confounded by patient comorbidities and has little utility in predicting overall lactate trend and 90-day hospital mortality. I’ll continue to use multiple parameters (urine output, MAP, capillary refill time, etc.) as well as lactate, with an understanding of its limitations.
Editor’s note: Lactate clearance appears to be less a marker of initial resuscitation quality and more a marker of which patients had better baseline health when they became septic. ~Clay Smith
Initial Lactate Clearance Is Confounded Highly by Comorbidities and Poorly Predicts Subsequent Lactate Trajectory. Chest. 2023 Sep;164(3):667-669. doi: 10.1016/j.chest.2023.04.023. Epub 2023 Apr 20.