Serum lactate cut-offs asarisk stratification tool for in-hospital adverse outcomes in emergency department patients screened for suspected sepsis

Abstract

ObjectivesWe investigated specific lactate thresholds for adverse outcomes in patients presenting to emergency departments (EDs) with suspected sepsis identified based on the performance of a sepsis screening algorithm.Design and settingA standardised sepsis bundle was implemented across public hospitals in New South Wales, Australia, as a quality improvement initiative. A register of all adult ED presentations (≥18 years) meeting predefined criteria for sepsis was created, using a combination of data linkage and direct reporting from 97 participating sites.ParticipantsA total of 12 349 adult ED presentations with 8310 (67.3%) having serum lactate analysis on arrival. Analysis of outcomes was based on dataset for 12 349 subjects obtained through multiple imputation for missing data.InterventionsA sepsis management bundle including early antibiotic prescribing, fluid therapy and referral to intensive care unit (ICU) services was implemented.Outcome measuresA primary composite adverse event (AE) outcome of inhospital mortality (IHM) and/or prolonged ICU stay ≥72 hours (ICU 72 hours) was used for this study.ResultsThere was statistically significant increase both in the ORs of AE and IHM with each integer increase in serum lactate values. After adjusting for the presence of hypotension, the estimated ORs for the combined AE outcome were 2.71 (95% CI 2.05 to 3.57), 2.65 (95% CI 2.29 to 3.08), 3.10 (95% CI 2.71 to 3.53) and 3.89 (95% CI 3.36 to 4.50) for serum lactate levels at or above 1, 2, 3 and 4 mmol/L, respectively. The corresponding ORs for IHM were 2.93 (95% CI 2.08 to 4.13), 2.77 (95% CI 2.34 to 3.29), 3.26 (95% CI 2.80 to 3.80) and 4.01 (95% CI 3.40 to 4.73), respectively (all P<0.0001). More than 10% of patients with suspected sepsis and with serum lactate ≥2 mmol/L experienced a prolonged ICU stay or died in hospital.ConclusionsED sepsis screening algorithms intended to identify patient adverse outcomes should incorporate a serum lactate cut-off of ≥2 mmol/L as a threshold for the initiation of specific interventions and increased monitoring.

Age-adjusted and Expanded Lactate Thresholds as Predictors of All-Cause Mortality in the Emergency Department

“…The existing literature evaluating lactate as a risk stratification tool for in-hospital mortality has predominantly looked at patients with the diagnosis of sepsis or trauma, raising the question of potential value of lactate use on the ED patient. 35,36 Our study is the first in a large population to show that there is a clinically relevant difference in mortality across both expanded lactate cohorts and age cohorts. A statistical difference in lactate levels between genders was also noted; however, this finding was beyond the scope of this paper and could be explored in future research.…”

“…The use of lactate as a diagnostic indicator, prognostic marker, and/or resuscitation endpoint in patients with various disease states has been well described in the literature and has become routine in ED clinical practice. 11,15,23,[29][30][31][32][33][34][35] However, traditional lactate-level thresholds (low < 2.0 mmol/L; intermediate 2.0 to 3.9 mmol/L; and high ≥ 4.0 mmol/L) have been used to guide care without regard to patient age or underlying disease state. 11 Expansion of these lactate-level thresholds and considerations of age and underlying disease states may prove useful in risk stratification and management decisions.…”

“…22 While lactate has been shown to be sensitive for occult sepsis, the current literature supports the notion that while it is highly sensitive, it is not specific. 23,35 Historically, the same lactate stratification levels have been used regardless of patient age or disease state: low levels, < 2.0 millimoles per liter (mmol/L); intermediate levels, 2.0-3.9 mmol/L; and high levels, ≥ 4.0 mmol/L. 2 Despite this cutoff of ≥ 4.0 mmol/L being used in models such as EGDT 21 and CMS criteria for septic shock, 24 the intermediate lactate level has also proven to be a high-risk group, as previously noted by Mikkelsen and Howell.…”

“… 22 While lactate has been shown to be sensitive for occult sepsis, the current literature supports the notion that while it is highly sensitive, it is not specific. 23 , 35 …”

Biomarkers in Sepsis: Value of Procalcitonin in Diagnosis and Prognostication

“…A recent Australian study disclosed that hyperlactatemia was proven to be more accurate in predicting mortality when compared to hypotension unresponsive to fluid replacement [5]. Shetty et al indicated that lactate levels >2 mmol/L in ED patients who were suspected to have sepsis are to be viewed as a risk predictor [6]. Also, these high levels of lactate was associated with in-hospital mortality rates greater than 10 percent and stay times in ICU longer than 72 hours in patients with respiratory and abdominal infectious foci in this study.…”