Lactate Clearance Measure Simplifies Severe Sepsis Therapy
A simpler method to monitor tissue oxygenation in severe sepsis led to short-term survival rates similar to those of the standard approach, and could ease initial management of critically ill patients, according to a report in JAMA.
Central venous oxygen saturation (ScvO2) monitoring is the third step in the protocol for early goal-directed therapy in severe sepsis, which is a complicated strategy for titrating intravenous fluids, pressors, inotropes such as dobutamine, and transfusions to quickly correct the imbalances associated with the disorder. With that approach, ScvO2 monitoring is used to assess whether dobutamine or red blood cell transfusions are restoring tissue oxygen delivery to a target value of at least 70%.
But ScvO2 monitoring is technically difficult, requiring expertise and special equipment that are not available in many emergency departments, the investigators noted, as well as “real-time calibration and troubleshooting that can divert attention from the patient.” A simpler and more generalizable method for monitoring the adequacy of tissue oxygen delivery is needed, said Dr. Alan E. Jones of the emergency department at Carolinas Medical Center, Charlotte, N.C., and his associates.
The researchers proposed using lactate clearance as such an alternative. Clearance of serum lactate is derived by calculating the change in lactate level from two blood specimens drawn at different times. A clearance of at least 10% can be used as a marker of adequate tissue oxygen delivery.
Dr. Jones and his colleagues performed a prospective, nonblinded clinical trial comparing the two methods in 300 patients who presented with severe sepsis or septic shock at emergency departments in three large urban medical centers. The study subjects were randomly assigned in equal numbers to receive either ScvO2 (central) monitoring or lactate clearance (serum) monitoring.
The primary end point of the study—the absolute in-hospital mortality rate—slightly favored the lactate clearance method (17% mortality) over ScvO2 (23% mortality). Thus, the less-invasive method was found to be noninferior, the investigators reported (JAMA 2010;303:739–46). “These data support the substitution of lactate measurements in peripheral venous blood as a safe and efficacious alternative to a [centrally placed] computerized spectrophotometric catheter in the resuscitation of sepsis,” they said.
Early goal-directed therapy and its constituent components “are currently being reevaluated in a number of large prospective clinical trials,” noted Dr. Roger J. Lewis of Harbor-UCLA Medical Center, Los Angeles, in an editorial comment. The study “is an important first step to identifying less burdensome approaches to the initial management of critically ill patients with severe sepsis and septic shock,” he wrote (JAMA 2010;303:777–9).
Disclosures: The study was supported by grants from the National Institutes of Health. Dr. Jones reported receiving research support from Critical Biologics Corp. and Hutchinson Technology Inc., and serving on an advisory board for Brahms Inc. and Siemens. Dr. Lewis chairs the data and safety monitoring board for the Protocolized Care for Early Septic Shock trial funded by NIH, and serves as a consultant to Berry Consultants LLC.
