Could lactate clearance be a marker of mortality in pediatric intensive care unit?

BACKGROUND: Hyperlactatemia is a common finding in critically ill patients and has significant prognostic implications. However, a single lactate measurement has not been correlated to mortality consistently. In this study, we aimed to correlate the clinical efficacy of lactate clearance for the prediction of mortality in pediatric intensive care unit patients. METHODS: This retrospective observational study was performed in the pediatric intensive care unit in patients with lactate level >3 mmol/lt. Initial, 6th h, and 24th h lactate levels were recorded and lactate clearance was calculated using these values (lactate level at admission - level 6 h later × 100/lactate level at admission). RESULTS: A total of 172 patients were included in the study. Forty-four out of 172 patients died. Median (IQR) lactate (mmol/L) at admission was low in those who survived in comparison to nonsurvivors 4.4 (3.1) vs. 5.75 (7.7) (p = 0.002). Clearance at 6th h was significantly lower in those who died (11.7%) than those who survived (36.7) (p = 0.001). 6th h lactate clearance level <20.7% predicted mortality with a sensitivity of 63.6% and specificity of 69.5% along with a positive predictive value of 41.8 and a negative predictive value of 84.8 (p = 0.004). Both lactate levels and lactate clearance values were significantly predictive factors for mortality (p < 0.05). Only a positive moderate correlation was found between the percentage of PRISM-IV % and 6th h lactate level. DISCUSSION: The present study revealed that lactate clearance is a simple and rapid risk-stratification tool holding to be a potential biomarker of managing the treatment efficacy of children in the pediatric intensive care unit.

Risk factors and in-hospital mortality of postoperative hyperlactatemia in patients after acute type A aortic dissection surgery.

BACKGROUND: Hyperlactatemia may be caused by increased production due to tissue hypoxia or non-hypoxia. The aim of this study was first to identify risk factors for postoperative hyperlactatemia (POHL) after Stanford type A acute aortic dissection surgery (AADS) and construct a predictive model, and second to evaluate the impact of POHL on prognosis. METHODS: This retrospective study involved patients undergoing AADS from January 2016 to December 2019 in Wuhan Union Hospital. Multivariate logistic regression analysis was performed to identify independent risk factors for POHL. A nomogram predicting POHL was established based on these factors and was validated in the original dataset. The receiver operating characteristic curve was drawn to assess the ability of postoperative lactate levels to predict the in-hospital mortality. RESULTS: A total of 188 patients developed POHL after AADS (38.6%). Male gender, surgery history, red blood cell transfusion and cardiopulmonary bypass time were identified as independent predictors. The C-index of the prediction model for POHL was 0.72, indicating reasonable discrimination. The model was well calibrated by visual inspection and goodness-of-fit test (Hosmer-Lemeshow χ2 = 10.25, P = 0.25). Decision and clinical impact curves of the model showed good clinical utility. The overall in-hospital mortality rate was 10.1%. Postoperative lactate levels showed a moderate predictive power for postoperative in-hospital mortality (C-index: 0.72). CONCLUSION: We developed and validated a prediction model for POHL in patients undergoing AADS, which may have clinical utility in personal risk evaluation and preventive interventions. The POHL could be a good predictor for in-hospital mortality.

Significance of lactate clearance in septic shock patients with high bilirubin levels.

Lactate clearance is affected by hepatic function. However, it is unclear whether the association between hepatic dysfunction and lactate clearance can act as a prognostic marker of clinical outcomes in patients with septic shock. We aimed to evaluate the association between lactate clearance and mortality in two cohorts of septic shock patient who had hepatic dysfunction based on their total serum bilirubin levels (TBIL). Lactate clearance at 24 h after the onset of septic shock was analyzed using two cohorts, sub-categorized into two groups based on TBIL: < 2 mg/dL and ≥ 2 mg/dL. In the derivation cohort, lactate clearance was lower in non-survivors than in survivors with TBIL ≥ 2 mg/dL, while there was no significant difference in lactate clearance between non-survivors and survivors with TBIL < 2 mg/dL. Multivariate logistic regression analysis revealed that increased lactate clearance was significantly associated with decreased 28-day mortality in the TBIL ≥ 2 mg/dL group (10% lactate clearance, adjusted odds ratio [OR]: 0.88, 95% confidence interval (CI): 0.80-0.97, P = 0.0075), Creatinine level ≥ 2 mg/dL group (adjusted OR: 0.88, 95% CI: 0.81-0.95, P = 0.00069) and APACHE II score ≥ 35 group (adjusted OR: 0.93, 95% CI: 0.87-0.98, P = 0.013). In the validation cohort, lactate clearance was lower in non-survivors than in survivors with TBIL ≥ 2 mg/dL, while no significant difference in lactate clearance was observed between non-survivors and survivors with TBIL < 2 mg/dL. Increased lactate clearance was significantly associated with decreased 28-day mortality in the TBIL ≥ 2 mg/dL group (10% lactate clearance, adjusted OR: 0.89, 95% CI: 0.83-0.96, P = 0.0038) and the association was just about significant in APACHE II score ≥ 35 group (adjusted OR: 0.86, 95% CI: 0.74-1.00, P = 0.051). In conclusion, increased lactate clearance in septic shock patients with hepatic dysfunction (TBIL ≥ 2 mg/dL) or high severity (APACHE II score ≥ 35) was associated with decreased 28-day mortality.

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.

Prognostic value of serum lactate kinetics in critically ill patients with cirrhosis and acute-on-chronic liver failure: a multicenter study.

Lactate clearance (Δ24Lac) was reported to be inversely associated with mortality in critically ill patients. The aim of our study was to assess the value of Δ24Lac for the prognosis of critically ill patients with cirrhosis and acute-on-chronic liver failure (ACLF). We analysed 954 cirrhotic patients with hyperlactatemia admitted to intensive care units (ICUs) in the United States and eastern China. The patients were followed up for at least 1 year. In the unadjusted model, we observed a 15% decrease in hospital mortality with each 10% increase in Δ24Lac. In the fully adjusted model, the relationship between the risk of death and Δ24Lac remained statistically significant (hospital mortality: odds ratio [OR] 0.84, 95% confidence interval [CI]: 0.78- 0.90, p < 0.001; 90-day mortality: hazard ratio [HR] 0.94, 95%CI 0.92- 0.97, p < 0.001; for Δ24Lac per 10% increase). Similar results were found in patients with ACLF. We developed a Δ24Lac-adjusted score (LiFe-Δ24Lac), which performed significantly better in the area under the receiver operating characteristic curves (AUROCs) than the original LiFe score for predicting mortality. Lactate clearance is an independent predictor of death, and the LiFe-Δ24Lac score is a practical tool for stratifying the risk of death.

Persistent hyperlactataemia is related to high rates of in-hospital adverse events and poor outcome in acute heart failure.

BACKGROUND: Although lactate is a well-established marker in intensive care, our understanding of its utility in acute heart failure (AHF) is modest and based on studies with a single measurement of this marker. AIM: We aimed to investigate whether persistent elevation of lactate during hospitalisation is related to a higher risk of ad- verse events. METHODS: We conducted a prospective study to assess AHF patients hospitalised in one cardiac centre. The diagnosis of persistent hyperlactataemia was based on two measurements of the marker (on admission and at 24 h of hospitalisation) and it was defined as lactate elevation (≥ 2 mmol/L) at both time points. RESULTS: The population consisted of 222 patients at a mean age of 70 ± 13 years. Mean ejection fraction and creatinine level on admission were 37% ± 16% and 1.36 ± 0.51 mg/dL, respectively. The percentage of patients with elevated lactates on admission, at 24 h of hospitalisation, and persistent hyperlactataemia were 47%, 35%, and 24%, respectively. The group with persistent hyperlactataemia did not differ in most clinical and laboratory variables from the rest of the population. Patients with persistent hyperlactataemia had higher rate of adverse events during hospitalisation: worsening of heart failure (22.6% vs. 6.5%, p < 0.05), inotrope use (22.6% vs. 5.3%, p < 0.05), and increase of N-terminal pro-B-type natriuretic peptide at 48 h of hospitalisation (30% vs. 18%, p < 0.05). Persistent hyperlactataemia was an independent predictor of one-year mortality (hazard ratio 2.5, 95% confidence interval 1.5-4.3, p < 0.001). CONCLUSIONS: Persistent hyperlactataemia within the first 24 h of hospitalisation is a predictor of a worse outcome in AHF and is related to higher rates of in-hospital adverse events and one-year mortality.

Risk factors for mortality in patients with low lactate level and septic shock.

BACKGROUND: According to the new definition of septic shock, vasopressor therapy and hyperlactatemia are essential for diagnosis. However, there is controversy regarding the cutoff value for lactate, and prognostic factors in patients with septic shock and hypolactatemia. This study evaluated the prognostic significance of the cutoff value for lactate level in septic shock patients. METHODS: The retrospective observational cohort study enrolled 1043 patients aged ≥18 years who meet the revised definition of septic shock. Clinical outcomes of patients with hyperlactatemia were compared with hypolactatemia. RESULTS: Of the 1022 eligible patients, 369 had an arterial lactate level ≤2 mmol/L. More patients in the high lactate group had poor prognosis than in the low lactate group. A high Sequential Organ Failure Assessment score (SOFA) score group was significant (p < 0.001) in predicting lactate levels. On the subgroup analysis of risk factors affecting mortality in the low lactate group, high Acute Physiology And Chronic Health Evaluation Ⅱ (APACHEⅡ) score (p = 0.003), high C-reactive protein (p = 0.034), and chronic heart failure (p = 0.001) were independently associated with 28-day mortality. CONCLUSION: Arterial lactate is a very reliable diagnostic and prognostic predictor of septic shock. However, despite low arterial lactate, patients with a high APACHEⅡ score, high C-reactive protein levels, and chronic heart failure had a poorer prognosis.

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.

Prognostic Value of Hyperlactatemia and Lactate Clearance After Mitral Valve Surgery.

OBJECTIVES: Blood lactate is frequently used to guide management in critically ill patients. In patients undergoing mitral valve surgery, an elevated lactate level is frequently observed; however, overall mortality is low. The authors hypothesized that hyperlactemia is not a useful predictor of poor outcomes in this patient population. The main aim of this study was to explore how blood lactate level and lactate clearance are associated with 30-day mortality and major adverse events in patients undergoing mitral valve surgery. DESIGN: This was a retrospective database review. Logistic regression analysis was performed to assess the associations of perioperative factors with blood lactate in the intensive care unit (ICU). SETTING: Tertiary-care teaching hospital. PARTICIPANTS: The study comprised 917 patients undergoing mitral valve surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The majority of patients (71.8%) had elevated blood lactate ≥2 mmol/L on ICU admission; however, within 24 hours, 85.1% of all patients had normal lactate values. Overall 30-day mortality was 2.29% (n = 21). The combination of lactate ≥7 mmol/L on ICU admission and a persistent elevated blood lactate level 24 hours after ICU admission provides an excellent prediction of 30-day mortality (C statistic = 0.85). However, even a significantly elevated lactate level on ICU admission was well-tolerated in the majority of patients as long as lactate values normalized within 24 hours. Male sex, longer cardiopulmonary bypass time, blood transfusion in the ICU, and an elevated blood lactate level on ICU admission and 12 hours after ICU admission all were independent risk factors of clearance failure. CONCLUSIONS: An elevated blood lactate level is common after mitral valve surgery and is well-tolerated in the majority of patients. Adding lactate clearance improved the predictive value of the blood lactate level.

Association of Clinical Hypoperfusion Variables With Lactate Clearance and Hospital Mortality.

BACKGROUND: Lactate has shown utility in assessing the prognosis of patients admitted to the hospital with confirmed or suspected shock. Some findings of the physical examination may replace it as screening tool. We have determined the correlation and association between clinical perfusion parameters and lactate at the time of admission; the correlation between the change in clinical parameters and lactate clearance after 6 and 24 h of resuscitation; and the association between clinical parameters, lactate, and mortality. METHODS: Prospective cohort study of adult patients hospitalized in the emergency room with infection, polytrauma, or other causes of hypotension. We measured serum lactate, capillary refill time, shock index, and pulse pressure at 0, 6, and 24 h after admission. A Spearman's correlation was performed between clinical variables and lactate levels, as well as between changes in clinical parameters and lactate clearance. The operative characteristics of these variables were determined by area under the receiver operating characteristic curve analysis and the association between lactate, clinical variables, and mortality through logistic regression. RESULTS: A total of 1,320 patients met the inclusion criteria, 66.7% (n = 880) confirmed infection, 19% (n = 251) polytrauma, and 14.3% (n = 189) another etiology. No significant correlation was found between any clinical variable and lactate values (r < 0.28). None of the variable had an adequate discriminatory capacity to detect hyperlactatemia (AUC < 0.62). In the multivariate model, lactate value at admission was the only variable independently associated with mortality (OR 1.2; 95% CI = 1.1-1.1). CONCLUSIONS: Among patients with hypoperfusion risk or shock, no correlation was found between clinical variables and lactate. Of the set of parameters collected, lactate at admission was the only independent marker of mortality.

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.

Capillary refill time during fluid resuscitation in patients with sepsis-related hyperlactatemia at the emergency department is related to mortality.

INTRODUCTION: Acute circulatory dysfunction in patients with sepsis can evolve rapidly into a progressive stage associated with high mortality. Early recognition and adequate resuscitation could improve outcome. However, since the spectrum of clinical presentation is quite variable, signs of hypoperfusion are frequently unrecognized in patients just admitted to the emergency department (ED). Hyperlactatemia is considered a key parameter to disclose tissue hypoxia but it is not universally available and getting timely results can be challenging in low resource settings. In addition, non-hypoxic sources can be involved in hyperlactatemia, and a misinterpretation could lead to over-resuscitation in an unknown number of cases. Capillary refill time (CRT) is a marker of peripheral perfusion that worsens during circulatory failure. An abnormal CRT in septic shock patients after ICU-based resuscitation has been associated with poor outcome. The aim of this study was to determine the prevalence of abnormal CRT in patients with sepsis-related hyperlactatemia in the early phase after ED admission, and its relationship with outcome. METHODS: We performed a prospective observational study. Septic patients with hyperlactemia at ED admission subjected to an initial fluid resuscitation (FR) were included. CRT and other parameters were assessed before and after FR. CRT-normal or CRT-abnormal subgroups were defined according to the status of CRT following initial FR, and major outcomes were registered. RESULTS: Ninety-five hyperlactatemic septic patients were included. Thirty-one percent had abnormal CRT at ED arrival. After FR, 87 patients exhibited normal CRT, and 8 an abnormal one. Patients with abnormal CRT had an increased risk of adverse outcomes (88% vs. 20% p<0.001; RR 4.4 [2.7-7.4]), and hospital mortality (63% vs. 9% p<0.001; RR 6.7 [2.9-16]) as compared to those with normal CRT after FR. Specifically, CRT-normal patients required less frequently mechanical ventilation, renal replacement therapy, and ICU admission, and exhibited a lower hospital mortality. CONCLUSIONS: Hyperlactatemic sepsis patients with abnormal CRT after initial fluid resuscitation exhibit higher mortality and worse clinical outcomes than patients with normal CRT.

Hyperlactatemia in ICU patients: Incidence, causes and associated mortality.

PURPOSE: To describe the incidence, causes and associated mortality of hyperlactatemia in critically ill patients and to evaluate the association between lactate clearance and in-hospital survival. METHODS: Retrospective cohort study of patients with hyperlactatemia admitted to the ICU. Hyperlactatemia was defined as a blood lactate concentration ≥5mmol/L and high-grade hyperlactatemia a lactate level ≥10mmol/L. Lactate clearance was calculated as the percentage of decrease in lactate concentration from the peak value. RESULTS: Of 10,123 patients, 1373 (13.6%) had lactate concentration ≥5mmol/L, and 434(31.6%) of them had ≥10mmol/L. The most common causes of hyperlactatemia were sepsis/septic shock and post-cardiac surgery. An association was found between lactate concentration and in-hospital mortality (p<0.001). The area under the receiver-operating-characteristics (ROC) of lactate concentration and the optimal cut off to predict mortality were 0.72 (0.70-0.75) and 8.6mmol/L, respectively. ROC analysis for lactate clearance to predict in-hospital survival showed that the best area under the curve was obtained at 12h: 0.67 (95% confidence interval 0.59-0.75). CONCLUSIONS: Hyperlactatemia was common and associated with a high mortality in critically ill patients. Lactate clearance had limited utility for predicting in-hospital survival.

Emergency department septic shock patient mortality with refractory hypotension vs hyperlactatemia: A retrospective cohort study.

BACKGROUND: Our objective was to compare in-hospital mortality among emergency department (ED) patients meeting trial-based criteria for septic shock based upon whether presenting with refractory hypotension (systolic blood pressure<90mmHg after 1L intravenous fluid bolus) versus hyperlactatemia (initial lactate≥4mmol/L). METHODS: We conducted a retrospective cohort analysis by chart review of ED patients admitted to an intensive care unit with suspected infection during 1 August 2012-28 February 2015. We included all patients with body fluid cultures sampled either during their ED stay without antibiotic administration or within 24h of antibiotic administration in the ED. We excluded patients not meeting criteria for either refractory hypotension or hyperlactatemia. Trained chart abstractors blinded to the study hypothesis double entered data from each patient's record including demographics, clinical data, treatments, and in-hospital mortality. We compared in-hospital mortality among patients with isolated refractory hypotension, isolated hyperlactatemia, or both. We also calculated odds ratios (ORs) via logistic regression for in-hospital mortality based on presence of refractory hypotension or hyperlactatemia. RESULTS: Of 202 patients included in the analysis, 38 (18.8%) died during hospitalization. Mortality was 10.9% among 101 patients with isolated refractory hypotension, 24.4% among 41 patients with isolated hyperlactatemia, and 28.3% among 60 patients with both (p=0.01). Logistic regression analyses yielded in-hospital mortality OR for refractory hypotension of 1.3 (95% CI 0.5-3.8) versus OR for hyperlactatemia of 2.9 (95% CI 1.2-7.4). CONCLUSIONS: Hyperlactatemia appears associated with higher in-hospital mortality compared to refractory hypotension among ED patients with septic shock.

Mortality is Greater in Septic Patients With Hyperlactatemia Than With Refractory Hypotension.

BACKGROUND: In septic patients, it is uncertain whether isolated hyperlactatemia (lactate ≥4 mmol/L without refractory hypotension) can be used to diagnose septic shock and whether mortality rate differs from that of isolated refractory hypotension (refractory to 1000 mL or greater fluid bolus). AIMS: To compare baseline characteristics, treatments, and outcomes of participants enrolled into the Australian Resuscitation in Sepsis Evaluation (ARISE) trial according to the presence of isolated hyperlactatemia or isolated refractory hypotension. PATIENTS: Cohort of 1,332 ARISE participants with sepsis and either isolated hyperlactatemia or isolated refractory hypotension. METHODS: We performed a secondary analysis of the ARISE data, constructing a propensity score model to discriminate between hyperlactatemia and isolated refractory hypotension. We analyzed 90-day all-cause mortality using a generalized linear model and inverse propensity score weighting. We modeled length of intensive care unit (ICU) and hospital stay using time to event analyses incorporating mortality as a competing risk. RESULTS: There were 478 participants (35.9%) with isolated hyperlactatemia and 854 (64.1%) with isolated refractory hypotension. They had similar median (interquartile range) ages (66.2 [54.2, 76.3] years vs. 65.2 [50.9, 75.5] years) and similar sources of infection. However, isolated hyperlactatemia participants had higher mean (standard deviation) baseline APACHE II scores (isolated hyperlactatemia 16.2 [6.4]) vs. 14.5 [6.4] for isolated refractory hypotension; P < 0.001). Isolated hyperlactatemia participants had a 1.7 times higher risk of 90-day mortality (propensity-weighted risk ratio; 95% confidence intervals [CI] 1.2, 2.5, P = 0.003). They were less likely to be discharged alive from ICU and hospital (propensity weighted sub-hazard ratio 0.77 (95% CI 0.64, 0.92; P < 0.005) and 0.79 (95% CI 0.66, 0.95; P = 0.01), respectively). CONCLUSIONS: ARISE trial participants with isolated hyperlactatemia had worse adjusted 90-day mortality than those with isolated refractory hypotension. In septic patients, isolated hyperlactatemia may define greater illness severity and worse outcomes than isolated refractory hypotension.

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.

Use of Postoperative Peak Arterial Lactate Level to Predict Outcome After Cardiac Surgery.

OBJECTIVES: In the present study, the authors investigated the predictive value of postoperative peak arterial lactate levels for early and late mortality after cardiac surgery. DESIGN: Retrospective analysis of prospectively collected data. SETTING: Single-center study in an academic hospital. PARTICIPANTS: Adult patients who underwent cardiac surgery between 2004 and 2014 (n = 16,376). INTERVENTIONS: Different cardiac surgical procedures. MEASUREMENTS AND RESULTS: Patients were classified according to the peak arterial lactate level (PALL) within 3 days postoperatively. Logistic regression analysis and Cox regression analysis were performed to identify postoperative peak arterial lactate level as a predictor for early and late mortality respectively. In 8460 patients (51.7%), lactate was not measured postoperatively because these patients were managed according to the fast-track protocol. These patients constituted group 1 in our population but were excluded from the regression analysis. The remaining patients (n = 7,916; 48.3%) were divided according to the postoperative peak arterial lactate level (PALL): PALL<5 mmol/L (group 2), PALL 5 to 10 mmol/L (group 3), and PALL of>10 mmol/L (group 4). Early mortality was 3.7%, 20.4%, and 62.9% in groups 2, 3, and 4 respectively (p<0.0001). This mortality rate was significantly higher than that of group 1 (1.6%); p<0.0001. Multivariate regression analyses revealed postoperative peak arterial lactate as a significant predictor of 30-day mortality (odds ratio = 1.44 [1.39-1.48], p<0.001) as well as for late mortality (hazard ratio = 1.05 [1.01-1.10], p<0.025). CONCLUSIONS: Postoperative peak arterial lactate level in patients undergoing cardiac surgery is an independent predictor for both early and late mortality.

Hyperlactatemia and the Importance of Repeated Lactate Measurements in Critically Ill Patients.

OBJECTIVE: The aim of the study was to describe the prevalence of hyperlactatemia and emphasis on repeated lactate measurements in critically ill patients, and the associated mortality. MATERIALS AND METHODS: The study included 70 patients admitted in the Medical Intensive Care Unit at the Clinical Center, University of Sarajevo, in a 6-month period (July - December 2015). The following data were obtained: age, gender, reason for admission, Simplified Acute Physiology Score II, Acute Physiology and Chronic Health Evaluation, lactate concentrations upon admission, after 24 and 48 hours, and outcome (discharge from hospital or death). RESULTS: Upon admission,hyperlactatemia was present in 91.4% patients with a mean concentration of lactate 4.13 ±1.21 mmol/L. Lactate concentration at 48 hours was independently associated within creased in-hospital mortality (P = 0.018). CONCLUSION: Persistent hyperlactatemia is associated with adverse outcome in critically ill patients. Lactate concentration at 48 hours is independently associated within creased in-hospital mortality and it represents a statistically significant predictive marker of fatal outcomes of patients. Blood lactate concentrations > 2.25 mmol/L should be used by clinicians to identify patients at higher risk of death.

Relationship Between Peak Lactate and Patient Outcome Following High-Risk Gastrointestinal Surgery: Influence of the Nature of Their Surgery: Elective Versus Emergency.

OBJECTIVES: The association between hyperlactatemia and adverse outcome in patients admitted to ICUs following gastrointestinal surgery has not been reported. To explore the hypothesis that in a large cohort of gastrointestinal surgical patients, the peak serum lactate (in the first 24 hr) observed in patients admitted to ICU following surgery is associated with unadjusted and severity-adjusted acute hospital mortality and that the strength of association is greater in patients admitted following "emergency" surgery than in patients admitted following "elective" surgery. DESIGN: A retrospective cohort study of all patients who had gastrointestinal surgery and were admitted directly to the ICU between 2008 and 2012. SETTING: Two hundred forty-nine hospitals in the United Kingdom. PATIENTS: One hundred twenty-one thousand nine hundred ninety patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Peak blood lactate in the first 24 hours of admission to critical care, acute hospital mortality, length of stay, and other variables routinely collected within the U.K. Intensive Care National Audit and Research Centre Case Mix Programme database. Elevated blood lactate was associated with increased risk of death and prolonged duration of stay, and the relationship was maintained once adjusted for confounding variables. The positive association between mortality and levels of blood lactate continued down into the "normal range," without evidence of a plateau. There was no difference in the extent to which hyperlactatemia was related to mortality between patients admitted following elective and emergency surgery. CONCLUSIONS: These findings have implications for our understanding of the role of lactate in critically ill patients.