Glucose Metabolism
Admission hyperlactatemia: Causes, incidence, and impact on outcome of patients admitted in a general medical intensive care unit

https://doi.org/10.1016/j.jcrc.2010.11.009Get rights and content

Abstract

Purpose

The aim of this study was to evaluate the causes, incidence, and impact on outcome of admission hyperlactatemia in patients admitted to a general medical intensive care unit (ICU).

Methods

A retrospective cohort study was done in an 8-bed general ICU of tertiary care hospital over 15 months. Data regarding patient demographics, probable cause of hyperlactatemia, presence of shock, need for organ support, and ICU outcome were recorded. Patients were divided into 2 groups based on admission lactate levels as follows: high lactate (>2 mmol/L) and normal lactate (<2 mmol/L). Patients were compared in terms of need for organ support and ICU mortality.

Results

Admission hyperlactatemia was present in 199 of 653 (30.47%) patients. Shock was the commonest cause, 53.3% patients, followed by respiratory and renal failure in 26 (13.1%) and 16 (8%) patients, respectively. Mean ± SD lactate levels in survivors and nonsurvivors were 1.64 ± 1.56 and 4.77 ± 4.72 mmol/L, respectively (P = .000). Receiver operating characteristic curve for lactate was 0.803 (95% confidence interval [CI], 0.753-0.853). Sensitivity and specificity of lactate (>2 mmol/L) to predict ICU mortality was 74.8% and 77.8%, respectively. Odds ratio for dying in patients with hyperlactatemia was 10.39 (95% CI, 6.378-16.925) with a relative risk of 1.538 (95% CI, 1.374-1.721). On subgroup analysis, in patients without hypotension too, ICU mortality was significantly increased in patients with hyperlactatemia (1.3% vs 6.45%, P = .009).

Conclusions

Admission hyperlactatemia is common in a general ICU and is associated with increased mortality, irrespective of presence of hypotension. Shock was the commonest cause for hyperlactatemia, followed by respiratory and renal failures.

Introduction

Serum lactate is one of the most widely used biomarkers for sepsis. Lactate levels rise early in the disease course and, hence, can be used as an early marker for organ failure and detection of occult shock before any detectable changes occur in a patient's vital signs [1], [2]. High lactate levels have been used in prehospital setting where also it has been shown to be associated with poor hospital outcome [1]. Hyperlactatemia at the time of admission has been shown to be a good prognostic marker [3], [4], but this finding is controversial, with many authors advocating sequential measurements of lactate to differentiate between survivors and nonsurvivors [5], [6]. Increased lactate levels have been shown to be associated with increased mortality in patients with shock, trauma, and sepsis [3], [5], [7], [8], [9], [10]. Nevertheless, blood lactate levels may be increased in a variety of other clinical conditions, but only a few studies have been conducted to evaluate the role of serum lactate levels in a general population of critically ill patients admitted in a medical intensive care unit (ICU) [10], [11]. Hence, we undertook this study to evaluate the causes, incidence, and impact on outcome of admission hyperlactatemia in patients admitted to a general medical ICU.

Section snippets

Setting

The study was carried out in a 500-bed tertiary care hospital with a fully equipped 8-bed medical ICU with an average of 600 admissions per year. The unit is based on closed-ICU model and is staffed by full-time intensivists.

Data collection

Data were retrospectively collected from the patient records for all the adult patients admitted in the medical ICU during the 15-month period ranging from July 2008 to September 2009. All ICU admissions were unscheduled. If the patient was admitted to the ICU more than

Results

Of the 807 admissions during the study period, data from 653 (80.9%) patients who fitted the inclusion criteria were analyzed. The probable causes of hyperlactatemia are given in Table 1. Admission hyperlactatemia was present in 199 patients (30.47%). The comparison between patients with normal and high lactates is given in Table 2.

The mean ± SD lactate levels among survivors were 1.64 ± 1.56 mmol/L as compared with mean levels of 4.77 ± 4.72 mmol/L among nonsurvivors (P = .000). The efficacy

Discussion

The incidence of hyperlactatemia at the time of ICU admission was 30.47% in the present study. The commonest attributable cause for hyperlactatemia in our cohort of patients was shock (53.3%), followed by respiratory (13.1%) and renal (8%) failures. Patients with hyperlactatemia had an increased need for organ support and ICU mortality. The AUROC for serum lactate level as a predictor of death was 0.803. Overall, the outcome was poorer in all subgroups of patients with hyperlactatemia

Conclusions

Admission hyperlactatemia is common in a general medical ICU and is associated with increased need for organ support and ICU mortality. The outcome of patients with admission hyperlactatemia is poorer irrespective of presence of hypotension. Admission hyperlactatemia can help us in identifying the patients at higher risk for death and, hence, can enable us to take immediate resuscitation measures to improve the overall outcome. Shock was the commonest cause for hyperlactatemia, followed by

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