The incidence and outcome of severe hyperlactatemia in critically ill patients

This study aimed to assess the incidence, persistence, and associated mortality of severe hyperlactatemia in a large cohort of unselected critically ill patients. Also, we evaluated the association between 12 h lactate clearance, the timing of severe hyperlactatemia, and the maximum lactate levels with ICU mortality. In this retrospective, single-center study, we used data from the Multiparameter Intelligent Monitoring in Intensive Care III (MIMIC-III) database. Data extracted to screen 23,598 ICU patients for severe hyperlactatemia. A total of 23,598 critically ill patients were eligible for this study. Overall, ICU mortality in the 23,598 ICU patients was 12.1%. Of these, 760 patients had lactate concentration [Formula: see text] 10 mmol/L and ICU mortality in this group was 65%. Our findings confirm the association between hyperlactatemia and ICU mortality [odds ratio 1.42 (95% CI 1.35; 1.49; P < 0.001)]. Data for 12 h lactate clearance was available for 443 patients (276 nonsurvivable vs. 167 survival). 12 h lactate clearance yielded a high area under the curve (AUC) of 0.78, (95% CI 0.74 and 0.83). Severe hyperlactatemia is associated with extremely high ICU mortality in a heterogeneous ICU population. Lactate derived variables (the timing and persistence of severe hyperlactatemia, maximum level, and 12 h clearance) are shown to be associated with ICU mortality in patients with severe hyperlactatemia. Our results suggest that maximum lactate level and 12 h lactate clearance were clinically useful prognostic parameters for patients with severe hyperlactatemia.

Base excess is superior to lactate-levels in prediction of ICU mortality after cardiac surgery

Introduction

Cardiac surgery with the use of cardiopulmonary bypass is known to induce distinct metabolic changes. Respective changes in acid-base status including increased systemic lactate levels were previously related to clinical outcomes, but data remain controversial. Therefore, we aim to investigate the relevance of lactate and base excess (BE) levels on ICU-mortality in patients admitted to the ICU after cardiac surgery.

Materials and methods

Perioperative data of patients treated in a tertiary care academic center admitted to the ICU after on-pump surgery were analyzed in a retrospective fashion. Receiver operation characteristic (ROC) curves were constructed for admission lactate-levels and BE with calculation of optimal cut-off values to predict ICU mortality. Univariate followed by multivariate regression models were constructed to identify potential outcome-relevant indices.

Results

Data from 1,058 patients were included in the analysis. Area under the curves for prediction of ICU mortality were 0.79 for lactate levels at ICU admission (sensitivity 61.9%/ specificity 87.5%; optimal cut-off level 3.9mmol/l), and 0.7 for BE (sensitivity 52.4%/ specificity 93.8%, optimal cut-off level -6.7), respectively. Multivariate regression identified BE < -6.7 as the single metabolic predictor of ICU-mortality (HR 4.78, 95%-CI 1.4–16.33, p = 0.01). Explorative subgroup analyses revealed that the combination of lactate ≤3.9mmol/l and BE ≤ -6.7 has stronger impact on mortality than a combination of lactate of >3.9mmol/l and BE > -6.7 (HR 2.56, 95%-CI 0.18–37.17).

Conclusions

At ICU-admission, severely reduced BE appears superior to hyperlactatemia with regard to prediction of ICU-mortality in patients after cardiac surgery.

Varying Presentations and Outcomes of Septic Shock: Should Septic Shock Be Stratified?

Recent studies have revealed there are three presentations of septic shock in patients: refractory hypotension without hyperlactatemia, hyperlactatemia without refractory hypotension, and both refractory hypotension and hyperlactatemia. In this study, we sought to identify differences in the outcomes of septic shock patients with these three presentations. We performed a secondary analysis of a large-scale, multicenter, controlled trial. The septic shock patients were categorized into the following three groups according to the presence or absence of refractory hypotension and hyperlactatemia: a hypotension group (refractory hypotension without hyperlactatemia), a hyperlactatemia group (hyperlactatemia without refractory hypotension), and a typical group (both refractory hypotension and hyperlactatemia). The 90-day all-cause mortality was compared among these three groups. A total of 1588 septic shock patients were enrolled in the present study, including 854 (53.8%) in the hypotension group, 477 (30.0%) in the hyperlactatemia group, and 257 (16.2%) in the typical group. The 90-day all-cause mortality were 12.3 per cent for the patients in the hypotension group, 23.1 per cent for those in the hyperlactatemia group, and 31.9 per cent for those in the typical group, these differences among the three groups were significant (Pearson's χ2 = 58.49, P < 0.001). And also, there was a significant difference between hyperlactatemia group and typical group (Pearson's χ2 = 6.77, P < 0.05). In this study, we demonstrated that the three different presentations of septic shock resulted in significantly different outcomes, suggesting that septic shock should be stratified.

Survival analysis of hypotensive cats admitted to an intensive care unit with or without hyperlactatemia: 39 cases (2005-2011)

OBJECTIVE To examine the association between blood lactate concentration and survival to hospital discharge in critically ill hypotensive cats. DESIGN Retrospective case series. ANIMALS 39 cats admitted to an intensive care unit of a university veterinary hospital between January 2005 and December 2011 for which blood lactate concentration was recorded ≤ 1 hour before or after a Doppler-derived arterial blood pressure measurement ≤ 90 mm Hg (ie, hypotension) was obtained. PROCEDURES Medical records of each cat were reviewed to assess survival to hospital discharge, illness severity, duration of hospitalization, age, body weight, and PCV. Results were compared between hypotensive cats with and without hyperlactatemia (blood lactate concentration ≥ 2.5 mmol/L). RESULTS 6 of 39 (15%) hypotensive cats survived to hospital discharge. Twelve (31%) cats were normolactatemic (blood lactate concentration < 2.5 mmol/L), and 27 (69%) were hyperlactatemic. Hypotensive cats with normolactatemia had a higher blood pressure and higher survival rate than hypotensive cats with hyperlactatemia. Five-day Kaplan-Meier survival rates were 57% for normolactatemic cats and 17% for hyperlactatemic cats. Age, body weight, duration of hospitalization, PCV, and illness severity did not differ significantly between hypotensive cats with and without hyperlactatemia. CONCLUSIONS AND CLINICAL RELEVANCE Hypotensive, normolactatemic cats in an intensive care unit had a significantly greater chance of survival to hospital discharge than their hyperlactatemic counterparts. Blood lactate concentration may be a useful prognostic indicator for this patient population when used in conjunction with other clinical and laboratory findings.

Prognostic value of plasma lactate levels in a retrospective cohort presenting at a university hospital emergency department

OBJECTIVES

The prognostic value of lactate in the setting of an emergency department (ED) has not been studied extensively. The goal of this study was to assess 28-day mortality in ED patients in whom lactate was elevated (≥4.0 mmol/L), <4.0 mmol/L or not determined and to study the impact of the underlying cause of hyperlactatemia, that is, type A (tissue hypoxia) or type B (non-hypoxia), on mortality.

DESIGN

Retrospective study.

SETTING

A secondary and tertiary referral centre in the Netherlands.

MATERIALS AND METHODS

All internal medicine patients with hyperlactatemia (≥4.0 mmol/L) at the ED between January 2011 and October 2014 were included in this study. Samples of patients with lactate levels <4.0 mmol/L and of patients in whom no lactate was measured were included as a reference.

RESULTS

In 1144 of 19 822 patients (5.8%), lactate was measured. Hyperlactatemia (n=197) was associated with a higher 28-day mortality than in those with lactate <4.0 mmol/L (40.6% vs 18.5%; p<0.001) and in those without lactate measurements (9.5%). Type A hyperlactatemia, present in 84% of those with hyperlactatemia, was associated with higher mortality than type B hyperlactatemia (45.8% vs 12.5%, p=0.001).

CONCLUSIONS

This study demonstrates that the prognostic value of lactate depends largely on the underlying cause and the population in whom lactate has been measured. Prospective studies are required to address the true added value of lactate at the ED.