Association between blood lactate levels, Sequential Organ Failure Assessment subscores, and 28-day mortality during early and late intensive care unit stay: a retrospective observational study

The Role of Monocyte Distribution Width (MDW) in the Prediction of Death in Adult Patients with Sepsis

Sepsis is a life-threatening condition; it is a major cause of hospital mortality worldwide and it constitutes a global health problem. This research investigates the use of MDW as a predictor for septic patients. This was a double-center prospective cohort study of adult septic patients. Septic patients were identified and were categorized into two categories: those who improved and those who died. Blood was drawn from the patients three times, on the first, third, and fifth day of their admission to the hospital. MDW was evaluated as a biomarker to predict patient outcome. In addition, existing inflammatory markers were recorded in all patients. The MDW was able to predict patient's outcome. The average MDW was found to be significantly higher in patients who died in all records. For example, an MDW value of 28.4 on the first day of admission to the hospital was shown to be the best cut-off value in determining fatal outcomes; receiver operating characteristic (ROC) analysis revealed an area under the curve value of 0.71 (95% Confidence Interval-CI: 0.57-0.84) with a sensitivity of 64.7% and a specificity of 88.2%. In conclusion, MDW, in addition to being a marker that can quickly detect sepsis more effectively than other biomarkers, which is proven by numerous studies, could also be used as an indicator to predict patient outcome. This work is an attempt in that direction.

Serial Lactate in Clinical Medicine - A Narrative Review

BACKGROUND

Blood lactate is commonly used in clinical medicine as a diagnostic, therapeutic and prognostic guide. Lactate's growing importance in many disciplines of clinical medicine and academic enquiry is underscored by the tenfold increase in publications over the past 10 years. Lactate monitoring is presently shifting from single to serial measurements, offering a means of assessing response to therapy and to guide treatment decisions. With the promise of wearable lactate sensors and their potential integration in electronic patient records and early warning scores, the utility of serial lactate measurement deserves closer scrutiny.

METHODS

Articles included in this review were identified by searching MEDLINE, PubMed and EMBASE using the term "lactate" alone and in combination with "serial", "point of care", "clearance", "prognosis" and "clinical". Authors were assigned vetting of publications according to their specialty (anesthesiology, intensive care, trauma, emergency medicine, obstetrics, pediatrics and general hospital medicine). The manuscript was assembled in multidisciplinary groups guided by underlying pathology rather than hospital area.

FINDINGS

Lactate's clinical utility as a dynamic parameter is increasingly recognized. Several publications in the last year highlight the value of serial measurements in guiding therapy. Outside acute clinical areas like the emergency room, operating room or intensive care, obtaining lactate levels is often fraught with difficulty and delays.

INTERPRETATION

Measuring serial lactate and lactate clearance offers regular feedback on response to therapy and patient status. Particularly on the ward, wearable devices integrated in early warning scores via the hospital IT system are likely to identify deteriorating patients earlier than having to rely on observations by an often-overstretched nursing workforce.

The microcirculation in cardiogenic shock

Cardiogenic shock is a life-threatening condition characterized by inadequate cardiac output, leading to end-organ hypoperfusion and associated mortality rates ranging between 40 and 50%. The critical role of microcirculatory impairments in the progression of organ failure during shock has been highlighted in several studies. Traditional therapies have often focused on stabilizing macrocirculation, neglecting microcirculatory dysfunction, which can result in persistent tissue hypoxia and poor outcomes. This review highlights the importance of assessing microcirculation in cardiogenic shock, including parameters such as skin perfusion, sublingual microcirculation, and lactate dynamics. Integrating microcirculatory assessments into clinical practice remains challenging due to the complexity of the methods and limited therapeutic options targeting microvascular perfusion. While advances in microcirculation-guided therapies hold promise for improving outcomes in cardiogenic shock, further research is needed to establish effective protocols.

Phosphodiesterase 3 inhibitors do not influence lactate kinetics and clinical outcomes in patients with septic shock: A multicentre cohort study

PURPOSE

We investigated the association between the administration of phosphodiesterase 3 inhibitors (PDE3i) and lactate kinetics, resolution of organ failure, ICU and hospital length of stay (LOS) and hospital mortality in a retrospective cohort of patients with septic shock and persistently elevated lactate concentrations.

MATERIAL AND METHODS

Patients with septic shock and two arterial lactate concentrations ≥4 mmol/L with at least 4 h between measurements were eligible. Clinical data of the first four days of admission were collected in an online database. For each patient, the area between the actual lactate concentrations and 2.2 mmol/L (AUClact2.2), was calculated for three days.

RESULTS

Data on 229 patients from 10 hospitals were collected, of whom 123 received PDE3i (54%). First, a linear multivariate model was developed to predict AUClact2.2 (R2 = 0.57). Adding PDE3i as a cofactor did not affect R2. Second, 60 patients receiving PDE3i at any time between days 0 and 2 were compared to 60 propensity matched no-PDE3i patients. Third, 30 patients who received PDE3i from ICU admission to day 3 were compared to 30 propensity-matched no-PDE3i patients. These analyses showed no differences in AUClact2.2, SOFA scores, ICU or hospital LOS or hospital mortality between treatment groups.

CONCLUSIONS

No association was found between the administration of PDE3i and lactate kinetics, resolution of organ failure, ICU or hospital LOS or hospital mortality.

Peripheral immune cell death in sepsis based on bulk RNA and single-cell RNA sequencing

Background

Immune cell activation in early sepsis is beneficial to clear pathogens, but immune cell exhaustion during the inflammatory response induces immunosuppression in sepsis. Here, we studied the relationship between immune cell survival status and the prognosis of sepsis patients.

Methods

Sepsis patients admitted to our hospital with a diagnosis time of less than 24 h were recruited. RNA sequencing technologies were used to study functional alterations in various immune cells in peripheral blood mononuclear cells (PBMCs) from sepsis patients. Flow cytometry and electron microscopy were performed to study cell apoptosis and morphological alterations.

Results

A total of 68 sepsis patients with complete data were enrolled and divided into survival (45 patients) and death (23 patients) groups according to their prognosis. Patients in the death group had significantly increased lactic acid levels compared with those in the survival group, but there was no significant difference in other physiological and coagulation functional indicators between the two groups. Bulk RNA sequencing showed that cell death-related pathways and biomarkers were highly enriched and activated in the PBMCs of the death group than that in the survival group. Signs of mitochondrial damage, autophagosomes, cell surface damage and cell surface pore forming were also more pronounced in PBMCs from the death group under electron microscopy. Further single-cell RNA sequencing revealed that cell death occurred mainly in myeloid cells rather than lymphocytes at the early stage of sepsis; cell death patterns of destructive necrosis and pyroptosis were predominant in neutrophils, and apoptosis, autophagy and ferroptosis with less damage to the surroundings were predominant in monocytes.

Conclusion

Cell death mainly occurs in monocytes and neutrophils in the PBMCs of sepsis at the early stage. The study provides a perspective for the immunotherapy of early sepsis targeting immune cell death.

The Value of the Sequential Organ Failure Assessment (SOFA) Score and Serum Lactate Level in Sepsis and Its Use in Predicting Mortality

Background and objective Sepsis is a major health burden that leads to significant morbidity and mortality. Early diagnosis and severity prediction using various scoring systems can reduce the mortality rate, particularly in developing nations. There are two aims of this study. One is to evaluate the prognostic accuracy of the Sequential Organ Failure Assessment (SOFA) score and serum lactate levels in patients with sepsis to predict mortality. The other aim is to evaluate the relationship between the SOFA score and lactate so that we may be able to use lactate as a surrogate predictor of organ dysfunction and mortality in sepsis. Methods An observational prognostic accuracy study was conducted in the Department of General Surgery, Intensive Care Unit (ICU), Rajendra Institute of Medical Sciences (RIMS), Ranchi, Jharkhand, India, between 1 July 2021 and 1 October 2022. We selected 128 patients, calculated their SOFA and lactate levels, and divided them into survivors and non-survivors according to their outcomes after seven days of assessment. The SOFA score and serum lactate levels were assessed as predictors of mortality, and their correlation was studied. Results We observed a significant decreasing trend in the value of the mean SOFA, maximum SOFA, mean lactate, and maximum lactate among survivors, whereas an increasing trend for the same was observed in non-survivors. The receiver operating characteristic (ROC) analysis showed the best diagnostic accuracy of the mean lactate (area under the curve {AUC}=0.996, 95% confidence interval {CI}=0.964-1.00, p≤0.0001). The maximum lactate (AUC=0.987, 95% CI=0.949-0.999, p≤0.0001) and mean SOFA scores (AUC=0.986, 95% CI=0.948-0.999, p≤0.0001) were good at predicting the mortality in sepsis. A slightly lower diagnostic accuracy was found for the maximum SOFA score (AUC=0.969, 95% CI=0.923-0.992, p≤0.0001). There was a strong correlation between the mean lactate and the mean SOFA with a correlation coefficient of 0.883 and p=0.0001. A good correlation was found between maximum lactate and maximum SOFA too (correlation coefficient=0.873, p≤0.0001). Conclusion This study highlights the different predictors of mortality in the patients with sepsis. The maximum lactate was the most accurate in predicting mortality in sepsis. It also demonstrates how serum lactate, due to its strong correlation with the SOFA score, can be used in its place to predict mortality in sepsis and organ dysfunction.

Predictive role of arterial lactate in acute kidney injury associated with off-pump coronary artery bypass grafting

Objectives

This observational study aims to explore the predictive role of postoperative arterial lactate in off-pump coronary artery bypass grafting (CABG)-associated acute kidney injury (AKI).

Materials and methods

A total of 500 consecutive patients who underwent off-pump CABG from August 2020 to August 2021 at the Department of Cardiovascular Surgery, Qilu Hospital of Shandong University, were included. Logistic regression analysis was used to confirm the independent risk factors of off-pump CABG-associated AKI. Receiver operating characteristic (ROC) curve was performed to evaluate the discrimination ability and Hosmer–Lemeshow goodness of fit test was performed to evaluate the calibration ability.

Results

The incidence of off-pump CABG-associated AKI was 20.6%. Female gender, preoperative albumin, baseline serum creatinine, 12 h postoperative arterial lactate and duration of mechanical ventilation were independent risk factors. The area under the ROC curve (AUC) of 12 h postoperative arterial lactate for predicting off-pump CABG-associated AKI was 0.756 and the cutoff value was 1.85. The prediction model that incorporated independent risk factors showed reliable predictive ability (AUC = 0.846). Total hospital stay, intensive care unit stay, occurrence of other postoperative complications, and 28-day mortality were all significantly higher in AKI group compared to non-AKI group.

Conclusion

12 h postoperative arterial lactate was a validated predictive biomarker for off-pump CABG-associated AKI. We constructed a predictive model that facilitates the early recognition and management of off-pump CABG-associated AKI.

Structural causal model with expert augmented knowledge to estimate the effect of oxygen therapy on mortality in the ICU

Recent advances in causal inference techniques, more specifically, in the theory of structural causal models, provide the framework for identifying causal effects from observational data in cases where the causal graph is identifiable, i.e., the data generation mechanism can be recovered from the joint distribution. However, no such studies have been performed to demonstrate this concept with a clinical example. We present a complete framework to estimate the causal effects from observational data by augmenting expert knowledge in the model development phase and with a practical clinical application. Our clinical application entails a timely and essential research question, the effect of oxygen therapy intervention in the intensive care unit (ICU). The result of this project is helpful in a variety of disease conditions, including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) patients in the ICU. We used data from the MIMIC-III database, a widely used health care database in the machine learning community with 58,976 admissions from an ICU in Boston, MA, to estimate the oxygen therapy effect on morality. We also identified the model's covariate-specific effect on oxygen therapy for more personalized intervention.

Incidence, risk factors and clinical outcomes of septic acute renal injury in cancer patients with sepsis admitted to the ICU: A retrospective study

Background

The purpose of this study was to clarify the incidence, risk factors, and clinical outcomes of septic acute kidney injury (AKI) in cancer patients with sepsis admitted to the intensive care unit (ICU).

Methods

A total of 356 cancer patients admitted to the ICU due to sepsis from January 2016 to October 2021 were analyzed retrospectively. According to the incidence of septic AKI, all patients were divided into the non-AKI group (n = 279) and the AKI group (n = 77). The clinical data after ICU admission were compared between the above two groups, and the risk factors and the clinical outcomes of septic AKI in the ICU were identified.

Results

The incidence of septic AKI in all patients was 21.6% (77/356). LASSO regression and logistic regression all showed that lactate, sequential organ failure assessment (SOFA) score and septic shock were closely related to the occurrence of septic AKI. In terms of clinical outcomes after ICU admission, the rate of mechanical ventilation (MV) and continuous renal replacement therapy (CRRT), MV time, hospitalization time and 28-day mortality in the ICU were significantly higher in the septic AKI group than in the non-septic AKI group. Among the three subgroups of septic AKI (AKI combined with septic shock, septic cardiac dysfunction or acute respiratory failure), the mortality of patients in the subgroup of AKI combined with septic shock was significantly higher than others. CRRT has no significant effect on the short-term outcome of these patients.

Conclusion

Lactate level, SOFA score and septic shock were closely related to the occurrence of septic AKI in the ICU. The clinical outcomes within 28 days after ICU admission of cancer patients with septic AKI were worse than those without septic AKI. The short-term outcome was worse in patients with septic AKI complicated with septic shock. CRRT does not have any significant effect on the short-term prognosis of cancer patients with septic AKI in the ICU.

Admission Lactate Concentration, Base Excess, and Alactic Base Excess Predict the 28-Day Inward Mortality in Shock Patients

Base excess (BE) and lactate concentration may predict mortality in critically ill patients. However, the predictive values of alactic BE (aBE; the sum of BE and lactate), or a combination of BE and lactate are unknown. The study aimed to investigate whether BE, lactate, and aBE measured on admission to ICU may predict the 28-day mortality for patients undergoing any form of shock. In 143 consecutive adults, arterial BE, lactate, and aBE were measured upon ICU admission. Receiver Operating Curve (ROC) characteristics and Cox proportional hazard regression models (adjusted to age, gender, forms of shock, and presence of severe renal failure) were then used to investigate any association between these parameters and 28-day mortality. aBE < −3.63 mmol/L was found to be associated with a hazard ratio of 3.19 (HR; 95% confidence interval (CI): 1.62−6.27) for mortality. Risk of death was higher for BE < −9.5 mmol/L (HR: 4.22; 95% CI: 2.21−8.05), particularly at lactate concentrations > 4.5 mmol/L (HR: 4.62; 95% CI: 2.56−8.33). A 15.71% mortality rate was found for the combined condition of BE > cut-off and lactate < cut-off. When BE was below but lactate above their respective cut-offs, the mortality rate increased to 78.91%. The Cox regression model demonstrated that the predictive values of BE and lactate were mutually independent and additive. The 28-day mortality in shock patients admitted to ICU can be predicted by aBE, but BE and lactate deliver greater prognostic value, particularly when combined. The clinical value of our findings deserves further prospective evaluation.

LACTATE IMPAIRS VASCULAR PERMEABILITY BY INHIBITING HSPA12B EXPRESSION VIA GPR81-DEPENDENT SIGNALING IN SEPSIS

ABSTRACT

Introduction: Sepsis impaired vascular integrity results in multiple organ failure. Circulating lactate level is positively correlated with sepsis-induced mortality. We investigated whether lactate plays a role in causing endothelial barrier dysfunction in sepsis. Methods: Polymicrobial sepsis was induced in mice by cecal ligation and puncture (CLP). Lactic acid was injected i.p. (pH 6.8, 0.5 g/kg body weight) 6 h after CLP or sham surgery. To elucidate the role of heat shock protein A12B (HSPA12B), wild-type, HSPA12B-transgenic, and endothelial HSPA12B-deficient mice were subjected to CLP or sham surgery. To suppress lactate signaling, 3OBA (120 μM) was injected i.p. 3 h before surgery. Vascular permeability was evaluated with the Evans blue dye penetration assay. Results: We found that administration of lactate elevated CLP-induced vascular permeability. Vascular endothelial cadherin (VE-cadherin), claudin 5, and zonula occluden 1 (ZO-1) play a crucial role in the maintenance of endothelial cell junction and vascular integrity. Lactate administration significantly decreased VE-cadherin, claudin 5, and ZO-1 expression in the heart of septic mice. Our in vitro data showed that lactate (10 mM) treatment disrupted VE-cadherin, claudin 5, and ZO-1 in endothelial cells. Mechanistically, we observed that lactate promoted VE-cadherin endocytosis by reducing the expression of HSPA12B. Overexpression of HSPA12B prevented lactate-induced VE-cadherin disorganization. G protein-coupled receptor 81 (GPR81) is a specific receptor for lactate. Inhibition of GPR81 with its antagonist 3OBA attenuated vascular permeability and reversed HSPA12B expression in septic mice. Conclusions: The present study demonstrated a novel role of lactate in promoting vascular permeability by decreasing VE-cadherin junctions and tight junctions in endothelial cells. The deleterious effects of lactate in vascular hyperpermeability are mediated via HSPA12B- and GPR81-dependent signaling.

Characteristics and predictors of ICU-mortality in critically ill patients with hyperlactatemia requiring CRRT: A retrospective cohort study

BACKGROUND

Hyperlactatemia is a common complication in critically ill patients with high morbidity and mortality. Hyperlactatemia patients who require continuous renal replacement therapy (CRRT) constitute a subgroup with increased mortality risk. The clinical significance of serum lactate in these patients was not well understood and clearance of lactate using CRRT shown no survival benefits. The aim of this study is to investigate the incidence and non-lactate risk factors for ICU mortality in hyperlactatemia patients who underwent CRRT.

METHOD

Hyperlactatemia patients with a serum lactate level >2 μmol/L who underwent CRRT between January, 2014 and May, 2021 were retrospectively investigated. Demographic characteristics and clinical data were collected from the electronic medical record system. The primary endpoint was predictors for ICU mortality which were identified by using multivariate logistic regression analysis.

RESULTS

A total of 178 eligible patients were finally included with a mean age of 56.6 ± 17.9 years and a median APACHE II score of 18 (IQR (14-22)). The multivariate regression results showed that male gender (OR 0.55 (95%CI 0.27-1.12), p = 0.1), mechanical ventilation (OR 2.60 (95%CI 1.27-5.34), p = 0.008), history of hypertension (OR 2.40 (95%CI 1.12-5.14), p = 0.02), SOFA score (OR 1.16 (95%CI 1.05-1.28), p = 0.002), AST (OR 1.0005 (95%CI 0.99-1.001), p = 0.08), and PT (OR 1.08 (95%CI 0.99-1.17), p = 0.06) were independently associated with ICU mortality. After adjusting for age, illness severity (APACHE II score), and serum lactate level, the statistical significances of SOFA score (OR 1.16 (95%CI 1.04-1.29), p = 0.005), hypertension (OR 2.25 (95%CI 1.02-4.95), p = 0.04), and mechanical ventilation (OR 2.54 (95%CI 1.22-5.25), p = 0.01) were not affected. The overall ICU mortality was 58.4% (104/178).

CONCLUSION

The hyperlactatemia patients who underwent CRRT were at increased ICU mortality. Gender, AST, PT, SOFA score, history of hypertension, and mechanical ventilation were independent predictors for ICU mortality. Future studies with prospectively design, large sample size, and subgroup analyses are warranted to validate these findings.

Risk stratification of patients with acute respiratory distress syndrome complicated with sepsis using lactate trajectories

Background

No consensus has been reached on an optimal blood lactate evaluation system although several approaches have been reported in the literature in recent years. A group-based trajectory modeling (GBTM) method could better stratify patients with acute respiratory distress syndrome (ARDS) complicated with sepsis in the intensive care unit (ICU).

Patients and methods

760 patients from the comprehensive ICU of Tianjin Medical University General Hospital with ARDS complicated with sepsis were eligible for analysis. Serial serum lactate levels were measured within 48 h of admission. In addition to the GBTM lactate groups, the initial lactate, peak lactate level, the area under the curve of serial lactate (lactate AUC), and lactate clearance were also considered for comparison. The short- and long-term outcomes were the 30- and 90-day mortality, respectively.

Results

Three lactate groups were identified based on GBTM, with group 3 exhibiting the worse short- [hazard ratio (HR) for 30-day mortality: 2.96, 95% confidence interval (CI) 1.79–4.87, P < 0.001] and long term (HR for 90-day mortality: 3.49, 95% CI 2.06–5.89, P < 0.001) outcomes followed by group 2 (HR for 30-day mortality: 2.05, 95% CI 1.48–2.84, P < 0.001 and HR for 90-day mortality: 1.99, 95% CI 1.48–2.67, P < 0.001). GBTM lactate groups exhibited significantly improved diagnostic performance of initial lactate + SOFA scores/APACHE II scores models. Based on the multivariable fractional polynomial interaction (MFPI) approach, GBTM lactate groups could better differentiate high-risk patients than the initial lactate groups in short- and long-term outcomes.

Conclusions

To the best of our knowledge, this is the first report that GBTM-based serial blood lactate evaluations significantly improve the diagnostic capacity of traditional critical care evaluation systems and bring many advantages over previously documented lactate evaluation systems.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02132-6.

Treatment of Hyperlactatemia in Acute Circulatory Failure Based on CO2-O2-Derived Indices: Study Protocol for a Prospective, Multicentric, Single, Blind, Randomized, Superiority Study (The LACTEL Study)

Background

Hyperlactatemia is a biological marker of tissue hypoperfusion with well-known diagnostic, prognostic, and therapeutic implications in shock states. In daily clinical practice, it is difficult to find out the exact mechanism underlying hyperlactatemia. Central venous to arterial CO₂ difference (pCO₂ gap) is a better parameter of tissue hypoperfusion than the usual ones (clinical examination and mixed venous saturation). Furthermore, the ratio between the pCO₂ gap and p(v–a)CO₂/C(a–v)O₂ may be a promising indicator of anaerobic metabolism, allowing for the identification of different causes of tissue hypoxia and hyperlactatemia. The main aim of the study is to demonstrate that initial hemodynamic resuscitation based on an algorithm integrating the pCO₂ gap and p(v–a)CO₂/C(a–v)O₂ ratio vs. usual clinical practice in acute circulatory failure improves lactate clearance.

Methods

LACTEL is a randomized, prospective, multicentric, controlled study. It compares the treatment of hyperlactatemia using an algorithm based on the pCO₂ gap and P(v–a)CO₂/C(a–v)O₂ ratio vs. usual clinical practice in acute circulatory failure. A total of 90 patients were enrolled in each treatment group. The primary endpoint is the number of patients with a lactate clearance of more than 10% 2 h after inclusion. Lactate levels were monitored during the first 48 h of treatment as hemodynamic parameters, biological markers of organ failure, and 28-day mortality.

Discussion

pCO₂ derivate indices may be of better interest than routine clinical indices to differentiate causes of hyperlactatemia and diagnose anaerobiosis. LACTEL results will provide clinical insights into the role of these indices in the early hemodynamic management of acute circulatory failure in the ICU.

Clinical Trial Registration

www.clinicaltrials.gov; identifier: NCT05032521.

Lactate, Base Excess, and the Pediatric Index of Mortality: Exploratory Study of an International, Multicenter Dataset

OBJECTIVES

To investigate the relationship between ICU admission blood lactate, base excess, and ICU mortality and to explore the effect of incorporating blood lactate into the Pediatric Index of Mortality.

DESIGN

Retrospective cohort study based on data prospectively collected on every PICU admission submitted to the U.K. Pediatric Intensive Care Audit Network and to the Australia and New Zealand Pediatric Intensive Care Registry.

SETTING

Thirty-three PICUs in the United Kingdom/Republic of Ireland and nine PICUs and 20 general ICUs in Australia and New Zealand.

PATIENTS

All ICU admissions between January 1, 2012, and December 31, 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred twenty-three thousand two hundred fifty-two admissions were recorded in both datasets; 81,576 (66.2%) in the United Kingdom/Republic of Ireland and 41,676 (33.8%) in Australia and New Zealand. Of these 75,070 (61%) had a base excess recorded, 63,316 (51%) had a lactate recorded, and 60,876 (49%) had both base excess and lactate recorded. Median lactate value was 1.5 mmol/L (interquartile range, 1-2.4 mmol/L) (United Kingdom/Republic of Ireland: 1.5 [1-2.5]; Australia and New Zealand: 1.4 [1-2.3]). Children with a lactate recorded had a higher illness severity, were more likely to be invasively ventilated, admitted after cardiac surgery, and had a higher mortality rate, compared with admissions with no lactate recorded (p < 0.001). The relationship between lactate and mortality was stronger (odds ratio, 1.32; 95% CI, 1.31-1.34) than between absolute base excess and mortality (odds ratio, 1.13; 95% CI, 1.12-1.14). Addition of lactate to the Pediatric Index of Mortality score led to a small improvement in performance over addition of absolute base excess, whereas adding both lactate and absolute base excess achieved the best performance.

CONCLUSIONS

At PICU admission, blood lactate is more strongly associated with ICU mortality than absolute base excess. Adding lactate into the Pediatric Index of Mortality model may result in a small improvement in performance. Any improvement in Pediatric Index of Mortality performance must be balanced against the added burden of data capture when considering potential incorporation into the Pediatric Index of Mortality model.

Lactate Albumin Ratio Is Associated With Mortality in Patients With Moderate to Severe Traumatic Brain Injury

Background

Traumatic brain injury (TBI) is a serious public health issue all over the world. This study was designed to evaluate the prognostic value of lactate to albumin ratio (LAR) on patients with moderate to severe TBI.

Methods

Clinical data of 273 moderate to severe TBI patients hospitalized in West China Hospital between May 2015 and January 2018 were collected. Multivariate logistic regression analyses were used to explore risk factors and construct a prognostic model of in-hospital mortality in this cohort. A receiver operating characteristic (ROC) curve was drawn to evaluate the discriminative ability of this model.

Results

Non-survivors had higher LAR than survivors (1.09 vs. 0.53, p < 0.001). Results of multivariate logistic regression analysis showed that Glasgow Coma Scale (GCS; odds ratio [OR] = 0.743, p = 0.001), blood glucose (OR = 1.132, p = 0.005), LAR (OR = 1.698, p = 0.022), subdural hematoma (SDH; OR = 2.889, p = 0.006), intraparenchymal hemorrhage (IPH; OR = 2.395, p = 0.014), and diffuse axonal injury (DAI; OR = 2.183, p = 0.041) were independent risk factors of in-hospital mortality in included patients. These six factors were utilized to construct the prognostic model. The area under the ROC curve (AUC) values of single lactate, albumin, and LAR were 0.733 (95% Cl; 0.673–0.794), 0.740 (95% Cl; 0.683–0.797), and 0.780 (95% Cl; 0.725–0.835), respectively. The AUC value of the prognostic model was 0.857 (95%Cl; 0.812–0.901), which was higher than that of LAR (Z = 2.1250, p < 0.05).

Conclusions

Lactate to albumin ratio is a readily available prognostic marker of moderate to severe TBI patients. A prognostic model incorporating LAR is beneficial for clinicians to evaluate possible progression and make treatment decisions in TBI patients.

Vasopressor Choice and Timing in Vasodilatory Shock

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2022. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2022 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from https://link.springer.com/bookseries/8901 .

Serum Lactate Level in Early Stage Is Associated With Acute Kidney Injury in Traumatic Brain Injury Patients

Background

Acute kidney injury (AKI) is a common complication in the clinical practice of managing patients with traumatic brain injury (TBI). Avoiding the development of AKI is beneficial for the prognosis of patients with TBI. We designed this study to testify whether serum lactate could be used as a predictive marker of AKI in patients with TBI.

Materials and Methods

In total, 243 patients with TBI admitted to our hospital were included in this study. Univariate and multivariate logistic regression analyses were utilized to analyze the association between lactate and AKI. The receiver operating characteristic (ROC) curves were drawn to verify the predictive value of lactate and the logistic model.

Results

Acute kidney injury group had higher age (p = 0.016), serum creatinine (p < 0.001), lactate (p < 0.001), and lower Glasgow Coma Scale (GCS; p = 0.021) than non-AKI group. Multivariate logistic regression showed that age [odds ratio (OR) = 1.026, p = 0.022], serum creatinine (OR = 1.020, p = 0.010), lactate (OR = 1.227, p = 0.031), fresh frozen plasma (FFP) transfusion (OR = 2.421, p = 0.045), and platelet transfusion (OR = 5.502, p = 0.044) were risk factors of AKI in patients with TBI. The area under the ROC curve (AUC) values of single lactate and predictive model were 0.740 and 0.807, respectively.

Conclusion

Serum lactate level in the early phase is associated with AKI in patients with TBI. Lactate is valuable for clinicians to evaluate the probability of AKI in patients with TBI.

Assessment of Metabolic Dysfunction in Sepsis in a Retrospective Single-Centre Cohort

Objective

Our primary aim was to assess selected metabolic dysfunction parameters, both independently and as a complement to the SOFA score, as predictors of short-term mortality in patients with infection admitted to the intensive care unit (ICU).

Methods

We retrospectively enrolled all consecutive adult patients admitted to the eight ICUs of Lille University Hospital, between January 2015 and September 2016, with suspected or confirmed infection. We selected seven routinely measured biological and clinical parameters of metabolic dysfunction (maximal arterial lactatemia, minimal and maximal temperature, minimal and maximal glycaemia, cholesterolemia, and triglyceridemia), in addition to age and the Charlson's comorbidity score. All parameters and SOFA scores were recorded within 24 h of admission.

Results

We included 956 patients with infection, among which 295 (30.9%) died within 90 days. Among the seven metabolic parameters investigated, only maximal lactatemia was associated with higher risk of 90-day hospital mortality in SOFA-adjusted analyses (SOFA-adjusted OR, 1.17; 95%CI, 1.10 to 1.25; p < 0.001). Age and the Charlson's comorbidity score were also statistically associated with a poor prognosis in SOFA-adjusted analyses. We were thus able to develop a metabolic failure, age, and comorbidity assessment (MACA) score based on scales of lactatemia, age, and the Charlson's score, intended for use in combination with the SOFA score.

Conclusions

The maximal lactatemia level within 24 h of ICU admission is the best predictor of short-term mortality among seven measures of metabolic dysfunction. Our combined "SOFA + MACA" score could facilitate early detection of patients likely to develop severe infections. Its accuracy requires further evaluation.

Machine Learning Consensus Clustering Approach for Patients with Lactic Acidosis in Intensive Care Units

BACKGROUND

Lactic acidosis is a heterogeneous condition with multiple underlying causes and associated outcomes. The use of multi-dimensional patient data to subtype lactic acidosis can personalize patient care. Machine learning consensus clustering may identify lactic acidosis subgroups with unique clinical profiles and outcomes.

METHODS

We used the Medical Information Mart for Intensive Care III database to abstract electronic medical record data from patients admitted to intensive care units (ICU) in a tertiary care hospital in the United States. We included patients who developed lactic acidosis (defined as serum lactate ≥ 4 mmol/L) within 48 h of ICU admission. We performed consensus clustering analysis based on patient characteristics, comorbidities, vital signs, organ supports, and laboratory data to identify clinically distinct lactic acidosis subgroups. We calculated standardized mean differences to show key subgroup features. We compared outcomes among subgroups.

RESULTS

We identified 1919 patients with lactic acidosis. The algorithm revealed three best unique lactic acidosis subgroups based on patient variables. Cluster 1 (n = 554) was characterized by old age, elective admission to cardiac surgery ICU, vasopressor use, mechanical ventilation use, and higher pH and serum bicarbonate. Cluster 2 (n = 815) was characterized by young age, admission to trauma/surgical ICU with higher blood pressure, lower comorbidity burden, lower severity index, and less vasopressor use. Cluster 3 (n = 550) was characterized by admission to medical ICU, history of liver disease and coagulopathy, acute kidney injury, lower blood pressure, higher comorbidity burden, higher severity index, higher serum lactate, and lower pH and serum bicarbonate. Cluster 3 had the worst outcomes, while cluster 1 had the most favorable outcomes in terms of persistent lactic acidosis and mortality.

CONCLUSIONS

Consensus clustering analysis synthesized the pattern of clinical and laboratory data to reveal clinically distinct lactic acidosis subgroups with different outcomes.

Machine Learning Prediction Models for Mortality in Intensive Care Unit Patients with Lactic Acidosis

BACKGROUND

Lactic acidosis is the most common cause of anion gap metabolic acidosis in the intensive care unit (ICU), associated with poor outcomes including mortality. We sought to compare machine learning (ML) approaches versus logistic regression analysis for prediction of mortality in lactic acidosis patients admitted to the ICU.

METHODS

We used the Medical Information Mart for Intensive Care (MIMIC-III) database to identify ICU adult patients with lactic acidosis (serum lactate ≥4 mmol/L). The outcome of interest was hospital mortality. We developed prediction models using four ML approaches consisting of random forest (RF), decision tree (DT), extreme gradient boosting (XGBoost), artificial neural network (ANN), and statistical modeling with forward stepwise logistic regression using the testing dataset. We then assessed model performance using area under the receiver operating characteristic curve (AUROC), accuracy, precision, error rate, Matthews correlation coefficient (MCC), F1 score, and assessed model calibration using the Brier score, in the independent testing dataset.

RESULTS

Of 1919 lactic acidosis ICU patients, 1535 and 384 were included in the training and testing dataset, respectively. Hospital mortality was 30%. RF had the highest AUROC at 0.83, followed by logistic regression 0.81, XGBoost 0.81, ANN 0.79, and DT 0.71. In addition, RF also had the highest accuracy (0.79), MCC (0.45), F1 score (0.56), and lowest error rate (21.4%). The RF model was the most well-calibrated. The Brier score for RF, DT, XGBoost, ANN, and multivariable logistic regression was 0.15, 0.19, 0.18, 0.19, and 0.16, respectively. The RF model outperformed multivariable logistic regression model, SOFA score (AUROC 0.74), SAP II score (AUROC 0.77), and Charlson score (AUROC 0.69).

CONCLUSION

The ML prediction model using RF algorithm provided the highest predictive performance for hospital mortality among ICU patient with lactic acidosis.

The Association of Serum Lactate Level with the Occurrence of Contrast-Induced Acute Kidney Injury and Long-Term Prognosis in Patients Undergoing Emergency Percutaneous Coronary Intervention

Objective

The association of lactate and contrast-induced acute kidney injury (CI-AKI) has not been well established. This prospective study was planned to identify the effects of lactate level on the occurrence of CI-AKI and long-term prognosis with acute myocardial infarction (AMI) patients undergoing emergency percutaneous coronary intervention (PCI).

Methods

A total of 280 patients with AMI who underwent emergency PCI were selected from March 2018 to March 2019. A receiver operating characteristic (ROC) curve was used to analyze the optimal cut-off value of lactate on predicting CI-AKI after PCI. A multivariable logistic regression model was used to explore the significant predictors that might affect the occurrence of CI-AKI after univariate analysis. The primary endpoints were clinical outcomes including events: a combined endpoint of major adverse cardiovascular events, re-hospitalization due to heart failure, and worsening renal function. The Cox regression model was further used to analyze the predictors of the long-term prognosis after PCI.

Results

Among the 280 patients, 64 patients (22.9%) developed CI-AKI after emergency PCI procedure. Multivariable logistic regression analysis revealed that baseline lactate level was the independent risk factor for the development of CI-AKI (OR, 3.657; 95% CI, 2.237–5.978; p<0.001). The area under the ROC curve for predicting CI-AKI of lactate was 0.786, and the optimum cut-off point of lactate was 3.02 mmol/L, with sensitivity of 65.6% and specificity of 85.2%. The incidence of primary endpoints in the high lactate group (lactate ≥3.02mmol/L) was significantly increased compared with the control group [26.3% (42/160) vs 15.8% (19/120), χ²=4.430, p=0.035]. Cox regression analysis also confirmed high lactate was an independent predictor for primary endpoint outcomes at 1-year follow-up (HR, 1.916; 95% CI, 1.118–3.285; p=0.018).

Conclusion

Our study demonstrates that baseline high lactate levels may be associated with an increased risk of CI-AKI and are the important predictors of long-term poor cardiorenal outcomes in AMI patients undergoing emergency PCI.

Hyperlactatemia associated with diabetic ketoacidosis in pediatric intensive care unit

BACKGROUND

Children with diabetic ketoacidosis often have elevated lactate. In this study, we investigated the clinical variables associated with hyperlactatemia in children with diabetic ketoacidosis.

METHODS

We designed a single-center retrospective descriptive study of children with diabetic ketoacidosis in a pediatric intensive care unit.

RESULTS

Of the 107 patients with diabetic ketoacidosis included in the analysis, 61 developed hyperlactatemia. Multivariate logistic regression analysis showed that heart rate (p = 0.003),diastolic blood pressure (p = 0.001) and stage of severity (p = 0.042) were independently associated with the development of hyperlactatemia in diabetic ketoacidosis. We found that lactate level was not significantly associated with length of hospital stay (p = 0.115) or the length of time to diabetic ketoacidosis resolution (p = 0.143).

CONCLUSIONS

Children with diabetic ketoacidosis presenting with severer stage, elevated heart rate and higher diastolic blood pressure may be prone to hyperlactatemia. Hyperlactatemia was not associated with length of time to DKA resolution and length of hospital stay.

Lactic Acidosis in Diabetic Ketoacidosis: A Marker of Severity or Alternate Substrate for Metabolism

PURPOSE

The lactate level is being increasingly used as a marker of severity of illness and prognosis in multitude of critical conditions. However, its role in diabetic ketoacidosis (DKA) is not well defined.

AIM

To determine the prevalence and clinical importance along with the underlying role of metformin in lactic acidosis (LA) in patients admitted with DKA.

METHODS

A 2-year prospective and observational study involving 62 consenting in hospital DKA patients. Plasma lactate level on arrival, its clinical significance and relationship with morbidity and mortality in patients with DKA was evaluated.

RESULTS

The prevalence of LA (lactate ≥2.5 mmol/l) among the study cohort was found to be 55% with significant LA (≥5 mmol/l) documented in 16%. The median lactate level was 2.55 mmol/l (interquartile range, 1.70-3.20). No significant difference in the severity of LA was seen with metformin use. Lactate correlated positively with initial plasma glucose (IPG) (P = 0.001) and APACHE-II Score (P = 0.002); correlated negatively with systolic blood pressure (P = 0.003), pH (P = 0.002) and severity of DKA (P = 0.001). After controlling for AKI, APACHE II score and blood pressure, lactate continued to correlate positively with IPG (P = 0.002). No mortality or significant morbidity was documented in the entire cohort.

CONCLUSIONS

LA has a significant presence in patients with DKA; however, it is not associated with mortality or significant morbidity. Moreover, there was no significant difference in severity of LA with metformin use. Elevated lactate levels may be an adaptation to provide alternate substrate for metabolism in the presence of hypoinsulinemic state. The study results provide rationale for large well-designed studies evaluating in-depth clinical relationship of lactate in DKA.

Association between serum lactate levels and enteral feeding intolerance in septic patients treated with vasopressors: a retrospective cohort study

Background

To assess the association between serum lactate levels and intolerance to enteral nutrition (EN) in septic patients treated with vasopressors.

Methods

This retrospective study was conducted between January 1, 2015 and May 1, 2018 in an intensive care unit (ICU). Patients with sepsis who were given EN and treated with vasopressors were included. EmpowerStats software and R (version 3.3.2) was used to examine the association between serum lactate levels and intolerance to EN.

Results

Among the 132 septic patients (age, 60.6±18.1 years) enrolled, 35 (26.5%) patients suffered intolerance to EN. Multiple logistic regression analysis demonstrated that an elevated lactate level was an independent risk factor for EN intolerance [odds ratio (OR): 2.7; 95% confidence interval (CI): 1.6–4.4; P<0.001]. The area under the receiver operating characteristic (ROC) curve for serum lactate levels was 0.764 (95% CI: 0.664–0.864). Stratified analysis suggested that age was the most prominent interactive factor for serum lactate levels in EN intolerance. Serum lactate levels were closely correlated to EN intolerance in elderly patients (age ≥65 years) (OR: 9.5; 95% CI: 2.1–42.4; P=0.0261 for interaction), while no such association was identified in younger patients (age <65 years; OR: 1.7; 95% CI: 1.0–2.9; P=0.052).

Conclusions

Serum lactate levels were associated with an increased risk of EN intolerance in patients with sepsis, especially in elderly individuals. An elevated serum lactate level may be an early predictor of EN intolerance in elderly septic patients treated with vasopressors. However, further studies are called for to verify these findings.

Serum Lactate Level Predicts Short-Term and Long-Term Mortality of HBV-ACLF Patients: A Prospective Study

Background

Acute chronic liver failure (ACLF) is a high-mortality disease characterized by rapid deterioration of liver function and multiple organ failure. The aim of this study was to assess the short-term and long-term predictive values of serum lactate in HBV-ACLF patients to facilitate early treatment and thereby improve patient survival.

Methods

We conducted a single-center, observational prospective study of 108 hospitalized patients. Biochemical examination and demographic data were obtained within 24 hours of admission. Logistics analysis was used to determine whether serum levels were independently for prognosis of HBV-ACLF patients. The area under ROC curve evaluates the prediction accuracy compared to the existing score.

Results

Serum lactate levels in nonsurviving patients were significantly higher than those in surviving patients. Logistics analysis demonstrated that serum lactate was an independent risk factor for 28-day, 3-month, and 6-month mortality. ROC curve evaluates the prediction efficiencies of serum lactate for 28-day, 3-month, and 6-month mortality. The AUROCs of new scores by adding lactate (Child-Pugh+ lactate score, MELD+ lactate score, MELD-Na+ lactate score, CLIF-C OF+ lactate score, CLIF-SOFA+ lactate score, CLIF-C ACLF+ lactate score) were superior to those of existing scores, particularly the MELD score and MELD-Na score (P<0.05) at all time points.

Conclusion

Serum lactate can be used as an effective indicator to predict the short-term and long-term mortality in HBV-ACLF patients, and the predictive value of the MELD score and MELD-Na was improved by adjusting for lactate. Lactate testing at admission can be beneficial in prognostic assessment and clinical decision-making.

Evaluation of an Anti-Thrombotic Continuous Lactate and Blood Pressure Monitoring Catheter in an In Vivo Piglet Model undergoing Open-Heart Surgery with Cardiopulmonary Bypass

Blood lactate and blood pressure measurements are important predictors of life-threatening complications after infant open-heart surgeries requiring cardiopulmonary bypass (CPB). We have developed an intravascular nitric oxide (NO)-releasing 5-Fr catheter that contains a lactate sensor for continuous in-blood lactate monitoring and a dedicated lumen for third-party pressure sensor attachment. This device has antimicrobial and antithrombotic properties and can be implanted intravascularly. The importance of this design is its ability to inhibit thrombosis, due to the slow release of NO through the surface of the catheter and around the electrochemical lactate sensors, to allow continuous data acquisition for more than 48 h. An in vivo study was performed using six piglets undergoing open-heart surgery with CPB and cardioplegic arrest, in order to mimic intra-operative conditions for infants undergoing cardiac surgery with CPB. In each study of 3 h, two 5-Fr NO-releasing lactate and blood-pressure monitoring catheters were implanted in the femoral vessels (arteries and veins) and the CPB circuitry to monitor changing lactate levels and blood pressures during and immediately after aortic cross-clamp removal and separation from CBP. Electrical signals continuously acquired through the sensors were processed and displayed on the device's display and via Bluetooth to a computer in real-time with the use of a two-point in vivo calibration against blood gas results. The study results show that lactate levels measured from those sensors implanted in the CPB circuit during CPB were comparable to those acquired by arterial blood gas measurements, whereas lactate levels measured from sensors implanted in the femoral artery were closely correlated with those acquired intermittently by blood gas prior to CPB initiation, but not during CPB. Blood pressure sensors attached to one lumen of the device displayed accurate blood pressure readings compared to those measured using an FDA approved pressure sensor already on the market. We recommend that the sensor be implanted in the CPB's circuit to continuously monitor lactate during CPB, and implanted in the femoral arteries or jugular veins to monitor lactate before and after CPB. Blood pressures dramatically drop during CPB due to lower blood flow into the lower body, and we suspect that the femoral arteries are likely collapsing or constricting on the implanted catheter and disrupting the sensor-to-blood contact. This study shows that the device is able to accurately and continuously monitor lactate levels during CPB and potentially prevent post-surgery complications in infants.

Early lactate area scores and serial blood lactate levels as prognostic markers for patients with septic shock: a systematic review

Septic shock is the main cause of morbidity and mortality in patients and second leading cause of mortality among subjects in noncoronary intensive care units. Based on the literature, elevated serum lactate levels are associated with poor outcomes in patients with septic shock, which may occur due to various reasons, such as tissue hypoxia and anaerobic metabolism. This systematic review was conducted to collect data on the lactate area and area under the curve (AUC) of serial lactate levels for the determination of the predictive values of these factors to diagnose septic shock. For this purpose, the articles published up to 2019 were searched in four databases, including Google Scholar, PubMed, Scopus, and Medline. This study was carried out based on the seven stages recommended in the Cochrane Handbook. All articles were searched using several keywords, including 'Lactate Area Score' and 'Serial Lactate Levels' in combination with 'Septic Shock'. There were a total of 14 studies mainly focused on the assessment of the lactate area and serial lactate levels in patients with septic shock. The inclusion criteria were a clear explanation of the predictive role of repeated lactate measurements in patients with septic shock, sample size larger than 50, examination on human samples, and publication in English. All case-control, prospective, and retrospective studies on human subjects assessing the predictive value of repeated lactate measurements in the diagnosis of patients with septic shock at high risk of mortality were entered in the present review. The lactate area is a new concept introduced as the sum of the AUC of serial lactate levels. This factor can determine the severity and duration of hyperlactatemia. Based on the obtained results, there was an association between the lactate area score and 28-day mortality of patients with septic shock; therefore, early lactate area score can be considered a prognostic marker for the prediction of mortality rate in these patients. There are few studies on the evaluation of the lactate area score and no more information about the prognostic ability of the lactate area score. This was the main limitation of the present study. Moreover, the lactate area is introduced as the sum of the AUC of serial lactate levels and cannot reflect the trend of serial lactate. The trend may be supported by lactate clearance but not lactate area.

Evaluation of accuracy of capillary refill index with pneumatic fingertip compression

Capillary refill time (CRT) is a method of measuring a patient's peripheral perfusion status through a visual assessment performed by a clinician. We developed a new method of measuring CRT using standard pulse oximetry sensor, which was designated capillary refill index (CRI). We evaluated the accuracy of CRI in comparison to CRT image analysis. Thirty healthy adult volunteers were recruited for a derivation study and 30 patients in the emergency department (ED) were for validation. Our high fidelity mechanical device compresses and releases the fingertip to measure changes in blood volume using infrared-light (940 nm). CRT was calculated by image analysis software using recorded fingertip videos. CRI and CRT were measured at: room temperature (ROOM TEMP), 15 °C cold water (COLD), and 38 °C warm water (REWARM). Intra-rater reliability, Bland-Altman plots, and correlation coefficients were used to evaluate the accuracy of the novel CRI method. CRI (4.9 [95% CI 4.5-5.3] s) and CRT (4.0 [3.6-4.3]) in the COLD group were higher than the ROOM TEMP and REWARM groups. High intra-rater reliability was observed in both measurements (0.97 [0.95-0.98] and 0.98 [0.97-0.99], respectively). The Bland-Altman plots suggested a systematic bias: CRI was consistently higher than CRT (difference: + 1.01 s). There was a strong correlation between CRI and CRT (r = 0.89, p < 0.001). ED patients had higher CRI (3.91 [5.05-2.75]) and CRT (2.21 [3.19-1.23]) than those of healthy volunteers at room temperature. The same difference and correlation patterns were verified in the ED setting. CRI was as reliable as CRT by image analysis. The values of CRI was approximately 1 s higher than CRT.

Utility of admission lactate concentration, lactate variables, and shock index in outcome assessment in dogs diagnosed with shock

OBJECTIVE

To determine whether admission venous plasma lactate concentration, calculated lactate variables, or shock index (SI) could discriminate hospital survivors from nonsurvivors in dogs admitted with shock.

DESIGN

Prospective investigation performed over a 19-month period.

SETTING

Large urban private teaching hospital.

ANIMALS

Twenty-three dogs consecutively admitted to the ICU from January 2008 to July 2009 with initial peripheral venous plasma lactate concentration >2 mmol/L (18.0 mg/dL) and clinical and hemodynamic parameters consistent with shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Heart rate, systolic blood pressure, and venous plasma lactate concentrations were serially recorded at predefined time points and used to calculate SI (SI = heart rate/systolic blood pressure) and lactate variables, including lactime (time lactate > 2.0 mmol/L), lactate clearance ([lactate_initial - lactate_delayed ]/lactate_initial × 100), and LAC_AREA (area under the lactate concentration versus time curve). Primary outcome was survival to discharge. Overall survival rate was 61%. Admission venous plasma lactate concentration did not differ between groups (P = 0.2). Lactime was shorter in survivors versus nonsurvivors (P = 0.02). Lactate clearance at 1, 10, 16, 24, and 36 hours, and final lactate clearance were greater in survivors versus nonsurvivors (P < 0.05). LAC_AREA at time intervals 0-1, 1-4, 4-10, 10-16, 16-24, 24-30, and 30-36 hours was larger in nonsurvivors versus survivors (P < 0.05). Total LAC_AREA did not differ between groups (P = 0.09). Admission SI and time to normalize SI (SI < 0.9) were not different between survivors and nonsurvivors (P > 0.05).

CONCLUSIONS

While admission venous plasma lactate concentration could not discriminate between hospital survivors and nonsurvivors, lactate variables showed clinical utility to predict outcome in dogs with shock. Further studies are needed to determine SI reference ranges and optimal SI cut-off values to improve its prognostic ability in sick dogs.

Lactate clearance prognosticates outcome in pediatric septic shock during first 24 h of intensive care unit admission

This study was undertaken to examine the clinical utility of lactate clearance as an indicator of mortality in pediatric septic shock, and to compare the performance of lactate clearance at 6, 12, and 24 h for predicting in-hospital and 60-day mortality. Pediatric patients with septic shock were prospectively studied. Vital signs, laboratory values, Pediatric Risk of Mortality Score, and pediatric logistic organ dysfunction score were obtained at presentation (hour 0), hour 6, hour 24 and over the first 72 h of hospitalization. Lactate clearance was obtained at 6, 12, and 24 h of hospital admission. Therapy received, outcome parameters of mortality, and duration of hospitalization were recorded. The primary outcome variable of 60-day mortality rate was 31.25%. Only lactate clearance at 6 and 24 h was significantly associated with mortality, with odds of 0.97 (95% CI, 0.951-981; p < 0.001) and 0.975 (95% CI, 0.964-0.986; p < 0.001), respectively. Approximately there was a 24% decrease in likelihood of mortality for each 10% increase in lactate clearance at 24 h. At a threshold value of 10% 6-h lactate clearance had a sensitivity of 0.948 and specificity of 0.571, while at a threshold of 20% 24-h lactate clearance had a sensitivity of 0.922 and specificity of 0.629. The comparison of clearance at 6 and 24 h using receiver operating characteristic showed that former was "fair" (area under the curve = 0.753) and later was "good" (area under the curve = 0.81) in predicting mortality in pediatric septic shock.

Conclusion

We concluded that optimal lactate clearance in pediatric septic shock both during the early presentation and after the initial "golden hours" is associated with lower in-hospital and 60-day mortality. Further, 24-h lactate clearance appears superior to 6 h lactate clearance in predicting mortality in such patients.

Serum Lactate as an Independent Predictor of In-Hospital Mortality in Intensive Care Patients

PURPOSE

The aim of this study was to check if serum lactate was independently associated with mortality among critically ill patients.

MATERIALS AND METHODS

This was a single-center, retrospective cohort study. All adult patients (>18 years of age) who had at least 1 measurement of lactate within 24 hours of admission to intensive care unit (ICU) between January 2002 and December 2017 were included in the analysis. Patients were stratified into 3 groups: those with a serum lactate of <2 mmol/L (normal level), 2 to 4 mmol/L (intermediate level), and >4 mmol/L (high level). The primary outcome was in-hospital mortality. Secondary outcomes included ICU and hospital lengths of stay and mechanical ventilation duration. To determine the association between lactate level and hospital mortality, bivariate and multivariate logistic regression analyses were performed.

RESULTS

Of the 16,447 patients admitted to the ICU, 8167 (49.65%) had normal levels, 4648 (28.26%) had an intermediate, and 3632 (22.09%) had high lactate levels. Hospital mortality was the highest in high lactate level, followed by the intermediate and the normal level group (47.4% vs 26.5% vs 19.6%; P < .0001). Intermediate and high lactate levels were independent predictors of hospital mortality (odds ratio [OR], 1.32; 95% confidence interval [CI]: 1.20-1.46, and 1.94; 95% CI, 1.75-2.16, respectively) as well as ICU mortality (OR, 1.47; 95% CI, 1.30-1.66 and 2.56; 95% CI, 2.27-2.88, respectively).

CONCLUSIONS

Intensive care unit serum lactate is associated with increased ICU and hospital mortality, independent of comorbidities, organ dysfunction, or hemodynamic status.

Prognostic accuracy of the serum lactate level, the SOFA score and the qSOFA score for mortality among adults with Sepsis

Background

Sepsis is a common critical condition caused by the body’s overwhelming response to certain infective agents. Many biomarkers, including the serum lactate level, have been used for sepsis diagnosis and guiding treatment. Recently, the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) recommended the Sequential Organ Failure Assessment (SOFA) and the quick SOFA (qSOFA) rather than lactate for screening sepsis and assess prognosis. Here, we aim to explore and compare the prognostic accuracy of the lactate level, the SOFA score and the qSOFA score for mortality in septic patients using the public Medical Information Mart for Intensive Care III database (MIMIC III).

Methods

The baseline characteristics, laboratory test results and outcomes for sepsis patients were retrieved from MIMIC III. Survival was analysed by the Kaplan-Meier method. Univariate and multivariate analysis was performed to identify predictors of prognosis. Receiver operating characteristic curve (ROC) analysis was conducted to compare lactate with SOFA and qSOFA scores.

Results

A total of 3713 cases were initially identified. The analysis cohort included 1865 patients. The 24-h average lactate levels and the worst scores during the first 24 h of ICU admission were collected. Patients in the higher lactate group had higher mortality than those in the lower lactate group. Lactate was an independent predictor of sepsis prognosis. The AUROC of lactate (AUROC, 0.664 [95% CI, 0.639–0.689]) was significantly higher than that of qSOFA (AUROC, 0.547 [95% CI, 0.521–0.574]), and it was similar to the AUROC of SOFA (AUROC, 0.686 [95% CI, 0.661–0.710]). But the timing of lactate relative to SOFA and qSOFA scores was inconsistent.

Conclusion

Lactate is an independent prognostic predictor of mortality for patients with sepsis. It has superior discriminative power to qSOFA, and shows discriminative ability similar to that of SOFA.

Electronic supplementary material

The online version of this article (10.1186/s13049-019-0609-3) contains supplementary material, which is available to authorized users.

Utility of the early lactate area score as a prognostic marker for septic shock patients in the emergency department

Background

The current Surviving Sepsis Campaign guidelines recommend the remeasurement of lactate levels if the initial lactate level is elevated; however, the prognostic value of lactate kinetics is limited and inconsistent. We attempted to determine the efficacy of the lactate area score (calculated from repeated lactate measurements during initial resuscitation) as a prognostic marker of septic shock in the emergency department (ED).

Methods

We performed a retrospective study of adult patients with septic shock in the ED of a single tertiary medical center. Serial lactate levels were measured five times within 12 hours. We also compared the initial lactate level, maximum lactate level, and lactate area score. The lactate area score was defined as the sum of the area under the curve measured at 2, 4, 6, and 12 hours following the initial measurement.

Results

A total of 362 patients were enrolled in this study, and the overall 28-day mortality was 31.8%. The lactate area score of serial lactate levels as well as the initial (median [interquartile range], 4.9 [3.4 to 10.5]; P=0.003) and maximum (7.3 [4.2 to 13.2]; P<0.001) lactate levels were significantly higher in the non-survivor group. However, in multivariate analysis, only the lactate area score (odds ratio, 1.013; 95% confidence interval, 1.007 to 1.019) was significantly associated with 28-day mortality.

Conclusions

The early lactate area score may be a possible prognostic marker for predicting the 28-day mortality of adult septic shock patients. Further prospective interventional studies should be conducted to validate our results.

The association of early postoperative lactate levels with morbidity after elective major abdominal surgery

Lactate levels are widely used as an indicator of outcome in critically ill patients. We investigated the prognostic value of postoperative lactate levels for postoperative complications (POCs), mortality and length of hospital stay after elective major abdominal surgery. A total of 195 patients were prospectively evaluated. Lactate levels were assessed on admission to the intensive care unit (ICU) [L0], at 4 hours (L4), 12 hours (L12), and 24 hours (L24) after the operation. Demographic and perioperative clinical data were collected. Patients were monitored for complications until discharge or death. Receiver operating characteristic (ROC) curves were used to determine the predictive value of lactate levels for postoperative outcomes. The best cut-off lactate values were calculated to differentiate between patients with and without complications, and outcomes in patients with lactate levels above and below the cut-off thresholds were compared. Univariate and multivariate analyses were used to identify variables associated with POCs and mortality. Seventy-six patients developed 184 complications (18 deaths), while 119 had no complications. Serum lactate levels were higher in patients with complications at all time points compared to those without complications (p < 0.001). L12 had the highest predictive value for complications (AUROC12 = 0.787; 95% CI: 0.719-0.854; p < 0.001) and mortality (AUROC12 = 0.872; 95% CI: 0.794-0.950; p < 0.001). The best L12 cut-off value for complications and mortality was 1.35 mmol/l and 1.85 mmol/l, respectively. Multivariate analysis revealed that L12 ≥ 1.35 mmol/l was an independent predictor of postoperative morbidity (OR 2.58; 95% CI 1.27-5.24, p = 0.001). L24 was predictive of POCs after major abdominal surgery. L12 had the best power to discriminate between patients with and without POCs and was associated with a longer hospital stay.

SOFA score in septic patients: incremental prognostic value over age, comorbidities, and parameters of sepsis severity

Several widely used scoring systems for septic patients have been validated in an ICU setting, and may not be appropriate for other settings like Emergency Departments (ED) or High-Dependency Units (HDU), where a relevant number of these patients are managed. The purpose of this study is to find reliable tools for prognostic assessment of septic patients managed in an ED-HDU. In 742 patients diagnosed with sepsis/severe sepsis/septic shock, not-intubated, admitted in ED between June 2008 and April 2016, SOFA, qSOFA, PIRO, MEWS, Charlson Comorbidity Index, MEDS, and APACHE II were calculated at ED admission (T0); SOFA and MEWS were also calculated after 24 h of ED-High-Dependency Unit stay (T1). Discrimination and incremental prognostic value of SOFA score over demographic data and parameters of sepsis severity were tested. Primary outcome is 28-day mortality. Twenty-eight day mortality rate is 31%. The different scores show a modest-to-moderate discrimination (T0 SOFA 0.695; T1 SOFA 0.741; qSOFA 0.625; T0 MEWS 0.662; T1 MEWS 0.729; PIRO: 0.646; APACHE II 0.756; Charlson Comorbidity Index 0.596; MEDS 0.674, all p < 0.001). At a multivariate stepwise Cox analysis, including age, Charlson Comorbidity Index, MEWS, and lactates, SOFA shows an incremental prognostic ability both at T0 (RR 1.165, IC 95% 1.009-1.224, p < 0.0001) and T1 (RR 1.168, IC 95% 1.104-1.234, p < 0.0001). SOFA score shows a moderate prognostic stratification ability, and demonstrates an incremental prognostic value over the previous medical conditions and clinical parameters in septic patients.

Soft tissue calcifications secondary to Hymenoptera stings: a potential prognostic CT imaging sign in pediatric patients

CONTEXT

Soft tissue calcifications (STCs) were incidentally found in some of the Hymenoptera-stung (HS) children when they underwent computed tomography (CT) scans for evaluating complications of vital organs. Afterwards, a predilection of STCs to the children with severe complications was clinically noticed. A hypothesis was then developed that STCs secondary to HS may correlate with poor outcomes.

OBJECTIVE

This study aims to firstly characterize the CT findings of STCs in HS children and to confirm our hypothesis that the occurrence of STCs may act as an indicator of poor outcomes in HS children.

MATERIALS AND METHODS

Children who received CT scanning after Hymenoptera sting from January 2011 to October 2016 in our hospital were analyzed retrospectively. Shape, location, and distribution of the STCs were described according to the CT findings. Then the enrolled cases were classified into Soft Tissue Calcification Group (STCG) and non-Soft tissue Calcification Group (non-STCG) to conduct prognostic comparisons of Sequential Organ Failure Assessment (SOFA) scores, incidence of main complications (acute liver failure (ALF), acute kidney injury stage III (AKI-III) and multiple organ failure (MOF)), length of hospital days, and in-hospital death, respectively. Pearson correlation was also utilized between the cumulative volume of STCs and the SOFA score.

RESULTS

Sixteen cases were enrolled, and STCs' incidence was 56.25% (9/16). Two STCG cases had diffuse nodular calcifications in their swollen subcutaneous tissue, and another seven had symmetrically stripy or patchy calcifications within or along local muscles. The SOFA scores during the first 3 days were all higher in STCG, and rose to the greatest difference at the third day (9.78 ± 2.17 vs. 2.29 ± 2.06, t = 7.009, p < .001); the incidence of ALF, AKI-III and MOF were significantly higher in STCG (66.67% vs. 0, p = .011), (77.78% vs. 0, p = .003) and (77.78% vs. 14.29%, p = .041); and children in STCG were treated with longer hospital durations (26.33 ± 8.41 days vs. 12.29 ± 7.36 days, t = 3.493, p = .004). One child in STCG died of cardiopulmonary failure, and no deaths occurred in non-STCG. No significant correlations presented between STCs cumulative volumes and SOFA score (r_Day1 = 0.096, p = .806; r_Day2 = 0.067, p = .863; r_Day3 = 0.024, p = .950).

CONCLUSION

Soft tissue calcifications detected on CT imaging following multiple Hymenoptera stings in pediatric patients may be a potential prognostic indicator of more severe complications and poorer outcomes.

Mildly elevated lactate levels are associated with microcirculatory flow abnormalities and increased mortality: a microSOAP post hoc analysis

Background

Mildly elevated lactate levels (i.e., 1–2 mmol/L) are increasingly recognized as a prognostic finding in critically ill patients. One of several possible underlying mechanisms, microcirculatory dysfunction, can be assessed at the bedside using sublingual direct in vivo microscopy. We aimed to evaluate the association between relative hyperlactatemia, microcirculatory flow, and outcome.

Methods

This study was a predefined subanalysis of a multicenter international point prevalence study on microcirculatory flow abnormalities, the Microcirculatory Shock Occurrence in Acutely ill Patients (microSOAP). Microcirculatory flow abnormalities were assessed with sidestream dark-field imaging. Abnormal microcirculatory flow was defined as a microvascular flow index (MFI) < 2.6. MFI is a semiquantitative score ranging from 0 (no flow) to 3 (continuous flow). Associations between microcirculatory flow abnormalities, single-spot lactate measurements, and outcome were analyzed.

Results

In 338 of 501 patients, lactate levels were available. For this substudy, all 257 patients with lactate levels ≤ 2 mmol/L (median [IQR] 1.04 [0.80–1.40] mmol/L) were included. Crude ICU mortality increased with each lactate quartile. In a multivariable analysis, a lactate level > 1.5 mmol/L was independently associated with a MFI < 2.6 (OR 2.5, 95% CI 1.1–5.7, P = 0.027).

Conclusions

In a heterogeneous ICU population, a single-spot mildly elevated lactate level (even within the reference range) was independently associated with increased mortality and microvascular flow abnormalities. In vivo microscopy of the microcirculation may be helpful in discriminating between flow- and non-flow-related causes of mildly elevated lactate levels.

Trial registration

ClinicalTrials.gov, NCT01179243. Registered on August 3, 2010.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1842-7) contains supplementary material, which is available to authorized users.

Utility of Volume Assessment Using Bioelectrical Impedance Analysis in Critically Ill Patients Receiving Continuous Renal Replacement Therapy: A Prospective Observational Study

Background

Fluid overload prior to continuous renal replacement therapy (CRRT) is an important prognostic factor. Thus, precise evaluation of fluid status is necessary to treat such patients. In this study, we investigated whether fluid assessment using bioelectrical impedance analysis (BIA) can predict outcomes in critically ill patients requiring CRRT.

Methods

A prospective observational study was performed in patients who were admitted to the intensive care unit and who required CRRT. BIA was conducted before CRRT; then, the ratio of extracellular water to total body water (ECW/TBW) was derived to estimate volume status.

Results

A total of 31 patients treated with CRRT were included. There were 18 men (58.1%), and the median age was 67 years (interquartile range, 51 to 78 years). Fourteen patients (45.2%) died within 28 days after CRRT initiation. Patients were divided into 16 with ECW/TBW ≥0.41 and 15 with ECW/TBW <0.41. Survival rate within 28 days was different between the two groups (P = 0.044). Cox regression analysis revealed a relationship between ECW/TBW ≥0.41 and 28-day mortality, but it was not statistically significant (hazard ratio, 3.0; 95% confidence interval, 0.9 to 9.8; P = 0.061). Lastly, the area under the curve of ECW/TBW for 28-day mortality was analyzed. The area under the curve of ECW/TBW was 0.73 (95% confidence interval, 0.54 to 0.92), and this was significant (P = 0.037).

Conclusions

Fluid status can be assessed using BIA in critically ill patients requiring CRRT, and BIA can predict mortality. Further large trials are needed to confirm the usefulness of BIA in critically ill patients.

Naso-intestinal tube is more effective in treating postoperative ileus than naso-gastric tube in elderly colorectal cancer patients

OBJECTIVE

The objective of this study was to compare the effect of naso-intestinal tube and naso-gastric tube in relieving postoperative ileus in elderly patients with colorectal cancer.

METHODS

Patients (n = 46) with ileus symptom following radical surgery for treating colorectal cancer were placed with either naso-intestinal tube at duodenum or conventional naso-gastric tube. Then, their waist perimeter, intra abdominal pressure, maximum diameter in bowls, length of time to pass flatus or passage of bowel movement or to return to diet, length of hospital stay, daily drainage, serum levels of lactic acid, hemoglobin, and creatinine as well were compared.

RESULTS

Naso-intestinal tube placement is more effective than naso-gastric tube in relieving intra abdominal pressures, reducing maximum bowl diameter and waist circumference, correcting serum lactic acid levels, alleviating analgesia dependence, regaining serum albumin level, increasing drainage and shortening the time of length of hospital stay, passing flatus or faces, and time to return to diet.

CONCLUSION

Naso-intestinal tube is effective in treating POI and shows advantage over conventional naso-gastric tube insertion.

Practical Use of Lactate Levels in the Intensive Care

Hyperlactatemia is a strong predictor of mortality in diverse populations of critically ill patients. In this article, we will give an overview of how lactate is used in the intensive care unit. We describe the use of lactate as a predictor of outcome, as a marker to initiate therapy and to monitor adequacy of initiated treatments.

Lactate levels and hemodynamic coherence in acute circulatory failure

In this review, the relationship between changes in macrohemodynamics during the development and treatment of acute circulatory failure is discussed in the context of coherence with microcirculation and changes in lactate. In models of circulatory failure, coherence between changes in macrocirculatory and microcirculatory perfusion and coherence with subsequent changes in lactate levels are more or less preserved. However, in patients, particularly those with septic shock, these relationships are much less clear. As many factors influence the effect of circulatory failure and infection on microcirculation and on lactate levels, this should not be surprising. Resuscitation should therefore aim at adequate tissue perfusion where systemic hemodynamics, microcirculatory perfusion parameters, and lactate levels should be used in their relevant context. This results in treating the individual patient as an n = 1 experiment.

The use of finger-stick blood to assess lactate in critically ill surgical patients

Background

Using finger-stick capillary blood to assess lactate from the microcirculation may have utility in treating critically ill patients. Our goals were to determine how finger-stick capillary lactate correlates with arterial lactate levels in patients from the surgical intensive care unit, and to compare how capillary and arterial lactate trend over time in patients undergoing resuscitation for shock.

Methods

Capillary whole blood specimens were obtained from finger-sticks using a lancet, and assessed for lactate via a handheld point-of-care device as part of an “investigational use only” study. Comparison was made to arterial blood specimens that were assessed for lactate by standard laboratory reference methods.

Results

40 patients (mean age 68, mean APACHEII 18, vasopressor use 62%) were included. The correlation between capillary and arterial lactate levels was 0.94 (p < 0.001). Capillary lactate measured slightly higher on average than paired arterial values, with a mean difference 0.99 mmol/L. In patients being resuscitated for septic and hemorrhagic shock, capillary and arterial lactate trended closely over time: rising, peaking, and falling in tandem. Clearance of capillary and arterial lactate mirrored clinical improvement, normalizing in all patients except two that expired.

Conclusion

Finger-stick capillary lactate both correlates and trends closely with arterial lactate in critically ill surgical patients, undergoing resuscitation for shock.

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Finger-stick capillary lactate correlates with blood gas and core lab values.

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Capillary lactate trends closely over time with arterial lactate.

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Rising or falling capillary lactate reflects the adequacy of global perfusion.

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Capillary lactate measurements require a fraction of the time and blood to process.

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Preliminary results imply capillary lactate may be used in lieu of invasive methods.