MULTICENTER STUDY OF EARLY LACTATE CLEARANCE AS A DETERMINANT OF SURVIVAL IN PATIENTS WITH PRESUMED SEPSIS

Is There an Effect of Initial and 24-Hour Blood Gas Lactate and Methemoglobin Levels on Predicting Mortality of Patients in the Intensive Care Unit?

In intensive care units (ICUs), serum lactate and methemoglobin (metHb) levels are considered significant biomarkers for predicting mortality in critically ill patients. This study investigates the relationship between lactate and metHb levels in blood gas analyses at admission and 24 h later, as well as their association with mortality in ICU patients. The study was conducted retrospectively between March and December 2022 at Adıyaman Training and Research Hospital, evaluating 114 patients, with statistical analyses performed on the collected data. The results indicated a statistically significant decrease in lactate levels between admission and 24 h after (p = 0.004). However, no significant change was found in metHb levels (p > 0.05). Lactate clearance was significantly lower in deceased patients compared to survivors (p = 0.037), whereas metHb clearance showed no statistically significant association with mortality. Lactate is highlighted as a key indicator of tissue hypoxia and plays a critical role in managing critically ill patients. Elevated lactate levels are associated with impaired oxygenation and worse prognoses. The literature consistently supports the association between high lactate levels and increased mortality in conditions such as sepsis and hemorrhagic shock. Similarly, this study confirms the prognostic value of lactate, particularly in the early phases of ICU admission. In contrast, metHb levels were not found to significantly impact mortality. Although some studies suggest a potential role of metHb as a biomarker for oxidative stress in inflammatory diseases, this relationship was not supported by the current findings. In conclusion, serum lactate levels serve as a crucial tool for mortality prediction and patient management in ICUs, while metHb levels have limited prognostic value. These findings suggest that greater emphasis should be placed on lactate monitoring in the management of critically ill patients.

Revisiting septic shock in cirrhosis: a call for personalized management

INTRODUCTION

Patients with cirrhosis are known to be prone to infections. Infections can trigger organ failures and decompensations in cirrhosis. Septic shock can increase mortality by fourfold and cause hemodynamic imbalances, adding to the already hyperdynamic circulation. Management of septic shock in cirrhosis can be tricky due to this complex interplay of altered hemodynamics, immune function, and coagulation.

AREAS COVERED

In this review, we explore the pathophysiological basis, screening, monitoring and management of septic shock in cirrhosis. We also explore novel biomarkers, the growing challenge of multidrug-resistant pathogens and novel and adjunctive therapies. Finally, we propose an algorithm for the management of septic shock in cirrhosis. We conducted a comprehensive search of electronic databases such as PubMed, Web of Science, and Cochrane Library using the keywords and MeSH terms like 'septic shock,' 'cirrhosis,' 'liver disease,' 'sepsis' among others. The search was restricted to peer-reviewed articles in English.

EXPERT OPINION

The difficulties in managing septic shock in cirrhosis are discussed, emphasizing personalized approaches over protocol-driven care. Fluid and vasopressor management, antibiotic timing and selection, the role of adjunctive therapies, the importance of lactate clearance, gut failure, and the need for further research in this population are highlighted.

Prognostic value of hyperlactatemia and lactate clearance in septic patients with hematological malignancies

BACKGROUND

The coexistence of sepsis and hematological malignancies increases patient vulnerability, revealing the need for precise prognostic markers. This study explores the prognostic significance of lactate levels and clearance in septic patients with hematological malignancies.

MATERIALS AND METHODS

A retrospective cohort study from January 2016 to December 2019 in a tertiary hematological intensive care unit (ICU) included 167 adults with hematological malignancies and sepsis. The relationship between lactate levels, hyperlactatemia, lactate clearance, and ICU outcomes was investigated. ICU survivors and non-survivors were compared to identify the factors affecting ICU mortality.

RESULTS

Patients were primarily with lymphoma and acute leukemia (66%) and had frequent hyperlactatemia (64%) on ICU admission. ICU non-survivors demonstrated higher lactate levels and hyperlactatemia frequency at various time points (0, 6, and 12 h) than survivors. Lactate clearance and liver function tests did not differ significantly between the two groups. Invasive mechanical ventilation [OR (95% confidence interval-CI): 20.4 (2.4-79.8), p < 0.01], requirement of vasopressors [OR (95% CI): 5.6 (1.3-24.5), p < 0.01], lactate level at the 6th hour [OR (95% CI): 1.51 (1.1-2.07), p = 0.01], and APACHE II score (OR (95% CI): 1.16 (1.01-1.34), p = 0.05) were independent risk factors for ICU mortality. The Area Under the Curve for APACHE II score and lactate level at the 6th hour were 0.774 (95% CI: 0.682-0.866) and 0.703 (95% CI: 0.602-0.804), respectively.

CONCLUSION

While elevated lactate levels correlate with mortality rate and lactate level at the 6th hour is an independent risk factor for mortality, the absence of a significant difference in lactate clearance challenges traditional assumptions. These results question the commonly accepted perspective regarding lactate dynamics in sepsis among individuals with hematological malignancies.

ORAL PRESENTATION

İnci K, et al. "Hyperlactatemia, lactate clearance and outcome in critically ill patients with hematological malignancies," 22nd ınternational intensive care symposium, 2019.

Prognostic Significance of Lactate Clearance in Cardiogenic Pulmonary Edema in the Emergency Department

Background and Objectives: Acute cardiorespiratory failure disrupts the delicate balance of energy supply, demand, and consumption, with elevated lactate levels and decreased blood pH serving as crucial indicators. Acute cardiogenic pulmonary edema (ACPO), a common cause of acute respiratory failure, poses a substantial mortality risk. Lactate, a byproduct of pyruvate reduction, is a pertinent marker in perfusion assessment. Lactate clearance (LC) has proven prognostic efficacy in various conditions but lacks consensus on its predictive power in acute cardiogenic pulmonary edema. Materials and Methods: This prospective observational study, conducted in a metropolitan area's third-level emergency department, involved patients with cardiogenic pulmonary edema from May 2021 to August 2023. The inclusion criteria specified acute cardiogenic pulmonary edema, excluding patients with incomplete data or other respiratory conditions. Lactate clearance, calculated at presentation and after 6 h, served as the primary outcome predictor. Our data analysis employed logistic regression, the ROC curve, and statistical tests. Results: The cohort of 106 patients revealed that a lactate clearance below 14.29% was significantly associated with mortality. While 51.6% of survivors were discharged, LC's predictive success for discharge was inconclusive. Logistic regression underscored the significance of lactate clearance, with a one-unit increase yielding a 5.55-fold probability of survival. The AUC for LC was 0.759. Conclusions: This study pioneers the exploration of lactate clearance in patients with acute cardiogenic pulmonary edema. LC below 14.29% signifies a poor prognosis, emphasizing its potential as an early treatment initiation marker. While acknowledging this study's limitations, we advocate for further multicenter research to refine the understanding of lactate clearance in this context.

Effects of dynamic versus static parameter-guided fluid resuscitation in patients with sepsis: A randomized controlled trial

Background

Fluid resuscitation is an essential component for sepsis treatment. Although several studies demonstrated that dynamic variables were more accurate than static variables for prediction of fluid responsiveness, fluid resuscitation guidance by dynamic variables is not standard for treatment. The objectives were to determine the effects of dynamic inferior vena cava (IVC)-guided versus (vs.) static central venous pressure (CVP)-guided fluid resuscitation in septic patients on mortality; and others, i.e., resuscitation targets, shock duration, fluid and vasopressor amount, invasive respiratory support, length of stay and adverse events.

Methods

A single-blind randomized controlled trial was conducted at Thammasat University Hospital between August 2016 and April 2020. Septic patients were stratified by acute physiologic and chronic health evaluation II (APACHE II) <25 or ≥25 and randomized by blocks of 2 and 4 to fluid resuscitation guidance by dynamic IVC or static CVP.

Results

Of 124 patients enrolled, 62 were randomized to each group, and one of each was excluded from mortality analysis. Baseline characteristics were comparable. The 30-day mortality rates between dynamic IVC vs. static CVP groups were not different (34.4% vs. 45.9%, p=0.196). Relative risk for 30-day mortality of dynamic IVC group was 0.8 (95%CI=0.5-1.2, p=0.201). Different outcomes were median (interquartile range) of shock duration (0.8 (0.4-1.6) vs. 1.5 (1.1-3.1) days, p=0.001) and norepinephrine (NE) dose (6.8 (3.9-17.8) vs. 16.1 (7.6-53.6) milligrams, p=0.008 and 0.1 (0.1-0.3) vs. 0.3 (0.1-0.8) milligram⋅kilogram -1, p=0.017). Others were not different.

Conclusions

Dynamic IVC-guided fluid resuscitation does not affect mortality of septic patients. However, this may reduce shock duration and NE dose, compared with static CVP guidance.

Effects of restrictive fluid therapy on the time to resolution of hyperlactatemia in ICU patients with septic shock. A secondary post hoc analysis of the CLASSIC randomized trial

PURPOSE

The aim of this study was to examine the effects of intravenous (IV) fluid restriction on time to resolution of hyperlactatemia in septic shock. Hyperlactatemia in sepsis is associated with worse outcome. Sepsis guidelines suggest targeting lactate clearance to guide fluid therapy despite the complexity of hyperlactatemia and the potential harm of fluid overload.

METHODS

We conducted a post hoc analysis of serial plasma lactate concentrations in a sub-cohort of 777 patients from the international multicenter clinical CLASSIC trial (restriction of intravenous fluids in intensive care unit (ICU) patients with septic shock). Adult ICU patients with septic shock had been randomized to restrictive (n = 385) or standard (n = 392) intravenous fluid therapy. The primary outcome, time to resolution of hyperlactatemia, was analyzed with a competing-risks regression model. Death and discharge were competing outcomes, and administrative censoring was imposed 72 h after randomization if hyperlactatemia persisted. The regression analysis was adjusted for the same stratification variables and covariates as in the original CLASSIC trial analysis.

RESULTS

The hazard ratios (HRs) for the cumulative probability of resolution of hyperlactatemia, in the restrictive vs the standard group, in the unadjusted analysis, with time split, were 0.94 (confidence interval (CI) 0.78-1.14) at day 1 and 1.21 (0.89-1.65) at day 2-3. The adjusted analyses were consistent with the unadjusted results.

CONCLUSION

In this post hoc retrospective analysis of a multicenter randomized controlled trial (RCT), a restrictive intravenous fluid strategy did not seem to affect the time to resolution of hyperlactatemia in adult ICU patients with septic shock.

Serum lactate normalization time associated with prolonged postoperative ileus after surgical management of the small bowel and/or mesenteric injuries

BACK GROUND

Determining the optimal timing of postoperative oral feeding in trauma patients who have undergone abdominal surgery with small bowel and/or mesenteric injuries is challenging. The aim of this study is to investigate serum lactate as a factor that can predict oral feeding tolerance and prolonged postoperative ileus (PPOI) in patients who underwent surgery for small bowel and/or mesenteric injury due to trauma.

METHODS

The single center retrospective observational study was conducted on 367 patients who underwent surgery for small bowel and/or mesenteric injury between January 2013 and July 2021. The patient group was divided into two groups based on whether the peak serum lactate was over 2mmol/L (18 mg/dL). In the group of lactate > 2mmol/L, it was divided into prolonged postoperative ileus (PPOI) groups and groups rather than PPOI.

RESULTS

Patients in the peak serum lactate > 2 group had tendency to use vasopressors, lower initial systolic blood pressure, larger number of packed red blood cells for 24 h, higher injury severity score, higher PPOI incidence, and a tendency for delayed oral intake tolerance. In peak serum lactate greater than 2 mmol/L group, the lactate normalization time (OR 1.699, p = 0.04), quantity of FFP transfusion for 24 h (OR 1.145, p = 0.012), and creatine kinase (OR 1.001, p = 0.023) were related to PPOI. The lactate normalization time had the highest correlation.

CONCLUSION

In patients undergoing surgical management for small bowel and/or mesenteric injury after trauma, serum lactate normalization time affects oral intake tolerance and prolongs postoperative ileus.

Utilizing the National Early Warning Score 2 (NEWS2) to confirm the impact of emergency department management in sepsis patients: a cohort study from taiwan 1998-2020

BACKGROUND

Most sepsis patients could potentially experience advantageous outcomes from targeted medical intervention, such as fluid resuscitation, antibiotic administration, respiratory support, and nursing care, promptly upon arrival at the emergency department (ED). Several scoring systems have been devised to predict hospital outcomes in sepsis patients, including the Sequential Organ Failure Assessment (SOFA) score. In contrast to prior research, our study introduces the novel approach of utilizing the National Early Warning Score 2 (NEWS2) as a means of assessing treatment efficacy and disease progression during an ED stay for sepsis.

OBJECTIVES

To evaluate the sepsis prognosis and effectiveness of treatment administered during ED admission in reducing overall hospital mortality rates resulting from sepsis, as measured by the NEWS2.

METHODS

The present investigation was conducted at a medical center from 1997 to 2020. The NEWS2 was calculated for patients with sepsis who were admitted to the ED in a consecutive manner. The computation was based on the initial and final parameters that were obtained during their stay in the ED. The alteration in the NEWS2 from the initial to the final measurements was utilized to evaluate the benefit of ED management to the hospital outcome of sepsis. Univariate and multivariate Cox regression analyses were performed, encompassing all clinically significant variables, to evaluate the adjusted hazard ratio (HR) for total hospital mortality in sepsis patients with reduced severity, measured by NEWS2 score difference, with a 95% confidence interval (adjusted HR with 95% CI). The study employed Kaplan-Meier analysis with a Log-rank test to assess variations in overall hospital mortality rates between two groups: the "improvement (reduced NEWS2)" and "non-improvement (no change or increased NEWS2)" groups.

RESULTS

The present investigation recruited a cohort of 11,011 individuals who experienced the first occurrence of sepsis as the primary diagnosis while hospitalized. The mean age of the improvement and non-improvement groups were 69.57 (± 16.19) and 68.82 (± 16.63) years, respectively. The mean SOFA score of the improvement and non-improvement groups were of no remarkable difference, 9.7 (± 3.39) and 9.8 (± 3.38) years, respectively. The total hospital mortality for sepsis was 42.92% (4,727/11,011). Following treatment by the prevailing guidelines at that time, a total of 5,598 out of 11,011 patients (50.88%) demonstrated improvement in the NEWS2, while the remaining 5,403 patients (49.12%) did not. The improvement group had a total hospital mortality rate of 38.51%, while the non-improvement group had a higher rate of 47.58%. The non-improvement group exhibited a lower prevalence of comorbidities such as congestive heart failure, cerebral vascular disease, and renal disease. The non-improvement group exhibited a lower Charlson comorbidity index score [4.73 (± 3.34)] compared to the improvement group [4.82 (± 3.38)] The group that underwent improvement exhibited a comparatively lower incidence of septic shock development in contrast to the non-improvement group (51.13% versus 54.34%, P < 0.001). The improvement group saw a total of 2,150 patients, which represents 38.41% of the overall sample size of 5,598, transition from the higher-risk to the medium-risk category. A total of 2,741 individuals, representing 48.96% of the sample size of 5,598 patients, exhibited a reduction in severity score only without risk category alteration. Out of the 5,403 patients (the non-improvement group) included in the study, 78.57% (4,245) demonstrated no alteration in the NEWS2. Conversely, 21.43% (1,158) of patients exhibited an escalation in severity score. The Cox regression analysis demonstrated that the implementation of interventions aimed at reducing the NEWS2 during a patient's stay in the ED had a significant positive impact on the outcome, as evidenced by the adjusted HRs of 0.889 (95% CI = 0.808, 0.978) and 0.891 (95% CI = 0.810, 0.981), respectively. The results obtained from the Kaplan-Meier analysis indicated that the survival rate of the improvement group was significantly higher than that of the non-improvement group (P < 0.001) in the hospitalization period.

CONCLUSION

The present study demonstrated that 50.88% of sepsis patients obtained improvement in ED, ascertained by means of the NEWS2 scoring system. The practical dynamics of NEWS2 could be utilized to depict such intricacies clearly. The findings also literally supported the importance of ED management in the comprehensive course of sepsis treatment in reducing the total hospital mortality rate.

Early post-operative lactate increase following kidney transplant is associated with delayed graft function: A retrospective cohort study

INTRODUCTION

Delayed graft function (DGF) is a frequent complication following kidney transplant. This study aimed to assess the association between early post-operative lactate variation and DGF.

METHODS

This was a single center, retrospective cohort study between February 2021 and December 2022 in Saint-Louis Hospital (APHP, France). Venous lactate levels were measured immediately (H0) and 4 h (H4) after kidney transplant. The primary outcome was the occurrence of DGF (need for renal replacement therapy between transplantation and day 7). Secondary outcome was the occurrence of complications (i.e., death, vascular thrombosis, hemorrhagic shock, urological complications (hematoma, urinoma), local or systemic infection) between transplant and day 7.

RESULTS

Two hundred 12 patients were included, and 38 (17.9%) developed DGF. Venous lactate variation between H0 and H4 was higher in patients who developed DGF (-30 (IQR -83, -6)% vs. -15 (IQR -62, -11)%, p = .037), but the variation of level was more often positive (corresponding to an increased lactate production over time between H0 and H4) in patients who developed DGF ((28(85%) vs. 94(62%), p = .011). In multivariate logistic regression, positive venous lactate level variation between H0 and H4 was strongly associated with a reduced risk of developing DGF (OR .30 [.09-.79], p = .024). We did not find any association between post-operative hyperlactatemia and occurrence of complications between transplant and day 7.

DISCUSSION

DGF is a frequent complication following kidney transplantation. Its early prediction could help physicians optimize treatment and protect the kidney. Early venous lactate variation after kidney transplant could help to predict the occurrence of DGF.

The Roles of Renal Oxygen Saturation in Septic Shock Children

Introduction

Septic shock, the most severe form of sepsis, has high morbidity and mortality rates among children. In patients with septic shock, impaired microcirculatory perfusion is associated with the severity of organ failure and the likelihood of death. Because near-infrared spectroscopy (NIRS) can assess microcirculation status and peripheral tissue oxygenation directly and noninvasively, provides real-time results, and can be performed at the patient's bedside. This study aimed to determine the prognostic value of renal oxygen saturation (rRSO2) measured by NIRS in septic shock among children.

Methods

This prospective observational study enrolled children aged 1 month to 18 years with septic shock who were treated in a pediatric intensive care unit from August 2020 to January 2021. NIRS was used to measure rRSO2 in patients diagnosed with septic shock according to the Third International Consensus Definition of Sepsis and Septic Shock. The baseline rRSO2 value (%) formed a receiver operating characteristic curve and was used to calculate the optimal cutoff value, sensitivity, specificity, and odds ratio (OR).

Results

We enrolled 24 patients, 13 nonsurvivors and 11 survivors, whose mean baseline rRSO2 values were 67.27 ± 12.95 versus 48.69 ± 16.17, respectively (P = 0.006). The optimal cutoff value for baseline rRSO2 was <60.5%, with a sensitivity of 76.9%, a specificity of 81.8%, and an area under curve 0.804 (95% confidence interval [CI]: 59.2%-98.1%, P = 0.012; OR = 15; 95 CI: 2.04-111.74).

Conclusion

Measured by NIRS, rRSO2 values are a good predictor of mortality among children with septic shock.

Rapid identification of sepsis in the emergency department

Objectives

Recent research has helped define the complex pathways in sepsis, affording new opportunities for advancing diagnostics tests. Given significant advances in the field, a group of academic investigators from emergency medicine, intensive care, pathology, and pharmacology assembled to develop consensus around key gaps and potential future use for emerging rapid host response diagnostics assays in the emergency department (ED) setting.

Methods

A modified Delphi study was conducted that included 26 panelists (expert consensus panel) from multiple specialties. A smaller steering committee first defined a list of Delphi statements related to the need for and future potential use of a hypothetical sepsis diagnostic test in the ED. Likert scoring was used to assess panelists agreement or disagreement with statements. Two successive rounds of surveys were conducted and consensus for statements was operationally defined as achieving agreement or disagreement of 75% or greater.

Results

Significant gaps were identified related to current tools for assessing risk of sepsis in the ED. Strong consensus indicated the need for a test providing an indication of the severity of dysregulated host immune response, which would be helpful even if it did not identify the specific pathogen. Although there was a relatively high degree of uncertainty regarding which patients would most benefit from the test, the panel agreed that an ideal host response sepsis test should aim to be integrated into ED triage and thus should produce results in less than 30 minutes. The panel also agreed that such a test would be most valuable for improving sepsis outcomes and reducing rates of unnecessary antibiotic use.

Conclusion

The expert consensus panel expressed strong consensus regarding gaps in sepsis diagnostics in the ED and the potential for new rapid host response tests to help fill these gaps. These finding provide a baseline framework for assessing key attributes of evolving host response diagnostic tests for sepsis in the ED.

The role of cardiac power and lactate clearance as an indicator of resuscitation success among pediatric patients with shock in the intensive care unit of Cipto Mangunkusumo Hospital

BACKGROUND

Shock in children remains the primary cause of mortality and morbidity worldwide. Furthermore, its management outcome is improved using many hemodynamic parameters, such as cardiac power (CP) and lactate clearance (LC). Cardiac power is a contractility index based on the measurement of flow and pressure, and it is a relatively new hemodynamic parameter with limited studies. In contrast, LC has been proven useful as a target outcome in shock resuscitation. This study aims to explore the values of CP and LC in pediatric shock and their association with clinical outcomes.

METHODS

This prospective observational study was conducted on children (1 month-18 years old) with shock at Cipto Mangunkusumo Hospital, Indonesia, from April to October 2021. We measured CP using ultrasonic cardiac output monitoring (USCOM®) and serum lactate levels at 0, 1, 6, and 24 h post-initial resuscitation. Subsequently, the variables were described and analyzed with the resuscitation success, length of stay, and mortality.

RESULTS

A total of 44 children were analyzed. There were 27 (61.4%), 7 (15.9%), 4 (9.1%), 4 (9.1%), and 2 (4.5%) cases of septic, hypovolemic, cardiogenic, distributive, and obstructive shock, respectively. Within the first 24 h post-initial resuscitation, CP and LC had an increasing trend. Compared to children who had successful resuscitation, those who did not have successful resuscitation had similar CP at all time points (p > 0.05) and lower LC at 1 and 24 h post-initial resuscitation (p < 0.05). Lactate clearance was an acceptable predictor of resuscitation success (area under the curve: 0.795 [95% CI: 0.660-0.931]). An LC of 7.5% had a sensitivity, specificity, positive predictive value, and negative predictive value of 75.00%, 87.5%, 96.43%, and 43.75%, respectively. Lactate clearance in the first hour post-initial resuscitation had a weak correlation (r=-0.362, p < 0.05) with hospital length of stay. We found no difference in CP and LC among survivors compared to nonsurvivors.

CONCLUSIONS

We found no evidence that CP was associated with resuscitation success, length of stay, or mortality. Meanwhile, higher LC was associated with successful resuscitation and shorter length of stay at the hospital, but not mortality.

Association of lactate detection with in-hospital mortality in critically ill patients with acute myocardial infarction: a retrospective cohort study

OBJECTIVES

To assess the associations of lactate level or lactate clearance at different time points with in-hospital mortality in critically ill patients with acute myocardial infarction (AMI).

DESIGN

A cohort study.

SETTING

The Medical Information Mart for Intensive Care III database.

PARTICIPANT

490 AMI patients.

INTERVENTION

None.

PRIMARY AND SECONDARY OUTCOME MEASURES

In-hospital mortality of patients.

RESULTS

In total, 120 (24.49%) patients died at the end of follow-up. After adjusting for confounders, increased risk of in-hospital mortality in patients with AMI was observed in those with high lactate level (24 hours) (HR=1.156, 95%CI: 1.002 to 1.333). Increased lactate clearance (24 hours) was correlated with a decreased risk of in-hospital mortality in patients with AMI (HR=0.995, 95% CI: 0.994 to 0.997). The area under the curves (AUCs) of lactate level (24 hours) and lactate clearance (24 hours) were 0.689 (95% CI: 0.655 to 0.723) and 0.672 (95% CI: 0.637 to 0.706), respectively. The AUC of lactate level (24 hours) and lactate clearance (24 hours) was higher than lactate level (baseline).

CONCLUSIONS

Increased lactate level (24 hours) was associated with an elevated risk of in-hospital mortality in patients with AMI and increased lactate clearance (24 hours) was correlated with a decreased risk of in-hospital mortality in patients with AMI despite the age and genders.

Rapid Measurement of Lactate in the Exhaled Breath Condensate: Biosensor Optimization and In-Human Proof of Concept

Lactate concentration is of increasing interest as a diagnostic for sepsis, septic shock, and trauma. Compared with the traditional blood sample media, the exhaled breath condensate (EBC) has the advantages of non-invasiveness and higher user acceptance. An amperometric biosensor was developed and its application in EBC lactate detection was investigated in this paper. The sensor was modified with PEDOT:PSS-PB, and two different lactate oxidases (LODs). A rotating disk electrode and Koutecky-Levich analysis were applied for the kinetics analysis and gel optimization. The optimized gel formulation was then tested on disposable screen-printed sensors. The disposable sensors exhibited good performance and presented a high stability for both LOD modifications. Finally, human EBC analysis was conducted from a healthy subject at rest and after 30 min of intense aerobic cycling exercise. The sensor coulometric measurements showed good agreement with fluorometric and triple quadrupole liquid chromatography mass spectrometry reference methods. The EBC lactate concentration increased from 22.5 μM (at rest) to 28.0 μM (after 30 min of cycling) and dropped back to 5.3 μM after 60 min of rest.

Severe hyperlactatemia in unselected surgical patients: retrospective analysis of prognostic outcome factors

Background

Etiology of hyperlactatemia in ICU patients is heterogeneous—septic, cardiogenic or hemorrhagic shock seem to be predominant reasons. Multiple studies show hyperlactatemia as an independent predictor for ICU mortality. Only limited data exists about the etiology of hyperlactatemia and lactate clearance and their influence on mortality. The goal of this single-center retrospective study, was to evaluate the effect of severe hyperlactatemia and reduced lactate clearance rate on the outcome of unselected ICU surgical patients.

Methods

Overall, 239 surgical patients with severe hyperlactatemia (> 10 mmol/L) who were treated in the surgical ICU at the University Medical Center Freiburg between June 2011 and August 2017, were included in this study. The cause of the hyperlactatemia as well as the postoperative course and the patient morbidity and mortality were retrospectively analyzed. Lactate clearance was calculated by comparing lactate level 12 h after first measurement of > 10 mmol/L.

Results

The overall mortality rate in our cohort was 82.4%. Severe hyperlactatemia was associated with death in the ICU (p < 0.001). The main etiologic factor was sepsis (51.9%), followed by mesenteric ischemia (15.1%), hemorrhagic shock (13.8%) and liver failure (9.6%). Higher lactate levels at ICU admission were associated with increased mortality (p < 0.001). Lactate clearance after 12 h was found to predict ICU mortality (ANOVA p < 0.001) with an overall clearance of under 50% within 12 h. The median percentage of clearance was 60.3% within 12 h for the survivor and 29.1% for the non-survivor group (p < 0.001).

Conclusion

Lactate levels appropriately reflect disease severity and are associated with short-term mortality in critically ill patients. The main etiologic factor for surgical patients is sepsis. When elevated lactate levels persist more than 12 h, survival chances are low and the benefit of continued maximum therapy should be evaluated.

Optimal Perfusion Targets in Cardiogenic Shock

Cardiology shock is a syndrome of low cardiac output resulting in end-organ dysfunction. Few interventions have demonstrated meaningful clinical benefit, and cardiogenic shock continues to carry significant morbidity with mortality rates that have plateaued at upwards of 40% over the past decade. Clinicians must rely on clinical, biochemical, and hemodynamic parameters to guide resuscitation. Several features, including physical examination, renal function, serum lactate metabolism, venous oxygen saturation, and hemodynamic markers of right ventricular function, may be useful both as prognostic markers and to guide therapy. This article aims to review these targets, their utility in the care of patients with cardiology shock, and their association with outcomes.

Increased normalized lactate load is associated with higher mortality in both sepsis and non-sepsis patients: an analysis of the MIMIC-IV database

Background

The present study aimed to evaluate the association between normalized lactate load, an index that incorporates the magnitude of change and the time interval of such evolution of lactate, and 28-day mortality in sepsis and non-sepsis patients. We also compared the accuracy of normalized lactate load in predicting mortality between these two populations.

Methods

Data were extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database. We defined lactate load as the sum of the area under the lactate concentration curve; we also defined normalized lactate load as the lactate load divided by time. The performance of maximum lactate, mean lactate and normalized lactate load in predicting 28-day mortality in sepsis and non-sepsis patients were compared by receiver-operating characteristic curves analysis.

Results

A total of 21,333 patients were included (4219 sepsis and 17,114 non-sepsis patients). Non-survivors had significantly higher normalized lactate load than survivors in sepsis and non-sepsis patients. The maximum lactate, mean lactate, and normalized lactate load AUCs were significantly greater in sepsis patients than in non-sepsis patients. Normalized lactate load had the greatest AUCs in predicting 28-day mortality in both sepsis and non-sepsis patients. Sensitivity analysis showed that the AUC of normalized lactate load increased in non-sepsis patients when more lactate measurement was obtained, but it was not improved in sepsis patients.

Conclusions

Normalized lactate load has the strongest predictive power compared with maximum or mean lactate in both sepsis and non-sepsis patients. The accuracy of normalized lactate load in predicting mortality is better in sepsis patients than in non-sepsis patients.

Improving sepsis care in Africa: an opportunity for change?

Sepsis is common and represents a major public health burden with significant associated morbidity and mortality. However, despite substantial advances in sepsis recognition and management in well-resourced health systems, there remains a distinct lack of research into sepsis in Africa. The lack of evidence affects all levels of healthcare delivery from individual patient management to strategic planning at health-system level. This is particular pertinent as African countries experience some of the highest global burden of sepsis. The 2017 World Health Assembly resolution on sepsis and the creation of the Africa Sepsis Alliance provided an opportunity for change. However, progress so far has been frustratingly slow. The recurrent Ebola virus disease outbreaks and the COVID-19 pandemic on the African continent further reinforce the need for urgent healthcare system strengthening. We recommend that African countries develop national action plans for sepsis which should address the needs of all critically ill patients.

Serum Lactate for Predicting Cardiac Arrest in the Emergency Department

Objectives: Early recognition and prevention of in-hospital cardiac arrest (IHCA) play an increasingly important role in the Chain of Survival. However, clinical tools for predicting IHCA in the emergency department (ED) are scanty. We sought to evaluate the role of serum lactate in predicting ED-based IHCA. Methods: Data were retrieved from 733,398 ED visits over a 7-year period in a tertiary medical centre. We selected one ED visit per person and excluded out-of-hospital cardiac arrest, children, or those without lactate measurements. Patient demographics, computerised triage information, and serum lactate levels were extracted. The initial serum lactate levels were grouped into normal (≤2 mmol/L), moderately elevated (2 < lactate ≤ 4), and highly elevated (>4 mmol/L) categories. The primary outcome was ED-based IHCA. Results: A total of 17,392 adult patients were included. Of them, 342 (2%) developed IHCA. About 50% of the lactate levels were normal, 30% were moderately elevated, and 20% were highly elevated. In multivariable analysis, the group with highly elevated lactate had an 18-fold increased risk of IHCA (adjusted odds ratio [OR], 18.0; 95% confidence interval [CI], 11.5-28.2), compared with the normal lactate group. In subgroup analysis, the poor lactate-clearance group (<2.5%/h) was associated with a 7.5-fold higher risk of IHCA (adjusted OR, 7.5; 95%CI, 3.7-15.1) compared with the normal clearance group. Conclusions: Elevated lactate levels and poor lactate clearance were strongly associated with a higher risk of ED-based IHCA. Clinicians may consider a more liberal sampling of lactate in patients at higher risk of IHCA with follow-up of abnormal levels.

[Which biomarkers for diagnosis and guidance of anti-infection treatment in sepsis?]

To date no biomarker has been identified bringing together perfect sensitivity and specificity to discriminate between inflammation and infections. Since the 1930s new markers of tissue damage and endothelial damage have been identified but which are incapable of identifying infections in every clinical setting to enable initiation of early antibiotic treatment. In this review the most important classical biomarkers and upcoming new PCR-based approaches are addressed. These markers are highlighted with respect to special clinical settings and to control the success of antibiotic treatment. The issue of discrimination between inflammation and infection is not yet solved. Based on one single biomarker it is impossible to decide whether infection is the reason for the patient's worsening condition but the combination of biomarkers or the integration of new biomarkers may be a meaningful supplement. The measurement of different biomarkers of infection or inflammation is part of the routine in critical care and will be essential in the future.

Association between dose of catecholamines and markers of organ injury early after out-of-hospital cardiac arrest

BACKGROUND

Catecholamines are recommended as first-line drugs to treat hemodynamic instability after out-of-hospital cardiac arrest (OHCA). The benefit-to-risk ratio of catecholamines is dose dependent, however, their effect on metabolism and organ function early after OHCA has not been investigated.

METHODS

The Post-Cardiac Arrest Syndrome (PCAS) pilot study was a prospective, observational, multicenter study. The primary outcomes of this analysis were association between norepinephrine/cumulative catecholamines doses and neuron specific enolase (NSE)/lactate concentration over the first 72 hours after resuscitation. The association was adjusted for proven OHCA mortality predictors and verified with propensity score matching (PSM).

RESULTS

Overall 148 consecutive OHCA patients; aged 18-91 (62.9 ± 15.27), 41 (27.7%) being female, were included. Increasing norepinephrine and cumulative catecholamines doses were significantly associated with higher NSE concentration on admission (r = 0.477, p < 0.001; r = 0.418, p < 0.001) and at 24 hours after OHCA (r = 0.339, p < 0.01; r = 0.441, p < 0.001) as well as with higher lactate concentration on admission (r = 0.404, p < 0.001; r = 0.280, p < 0.01), at 24 hours (r = 0.476, p < 0.00; r = 0.487, p < 0.001) and 48 hours (r = 0.433, p < 0.01; r = 0.318, p = 0.01) after OHCA. The associations remained significant up to 48 hours in non-survivors after PSM.

CONCLUSIONS

Increasing the dose of catecholamines is associated with higher lactate and NSE concentration, which may suggest their importance for tissue oxygen delivery, anaerobic metabolism, and organ function early after OHCA.

Lactate Is a Metabolic Mediator That Shapes Immune Cell Fate and Function

Lactate and the associated H⁺ ions are still introduced in many biochemistry and general biology textbooks and courses as a metabolic by-product within fast or oxygen-independent glycolysis. However, the role of lactate as a fuel source has been well-appreciated in the field of physiology, and the role of lactate as a metabolic feedback regulator and distinct signaling molecule is beginning to gain traction in the field of immunology. We now know that while lactate and the associated H⁺ ions are generally immunosuppressive negative regulators, there are cell, receptor, mediator, and microenvironment-specific effects that augment T helper (Th)17, macrophage (M)2, tumor-associated macrophage, and neutrophil functions. Moreover, we are beginning to uncover how lactate and H⁺ utilize different transporters and signaling cascades in various immune cell types. These immunomodulatory effects may have a substantial impact in cancer, sepsis, autoimmunity, wound healing, and other immunomodulatory conditions with elevated lactate levels. In this article, we summarize the known effects of lactate and H⁺ on immune cells to hypothesize potential explanations for the divergent inflammatory vs. anti-inflammatory effects.

Clinical significance of lactate clearance in patients with cardiogenic shock: results from the RESCUE registry

Background

Limited data are available on the clinical significance of lactate clearance (LC) in patients with cardiogenic shock (CS). This study investigated the prognostic role of LC in CS patients.

Methods

We analyzed data from 628 patients in the RESCUE registry, a multicenter, observational cohort enrolled between January 2014 and December 2018. Univariable logistic regression analysis was performed to determine the prognostic implications of 24 h LC, and then patients were divided into two groups according to the cut-off value of 24 h LC (high lactate clearance [HLC] group vs. low lactate clearance [LLC] group). The primary outcome was in-hospital mortality. We also assessed all-cause mortality at 12 month follow-up and compared the prognostic performance of 24 h LC according to initial serum lactate level.

Results

In the univariable logistic regression analysis, 24 h LC was associated with in-hospital mortality (odds ratio 0.989, 95% confidence interval [CI] 0.985–0.993, p < 0.001), and the cut-off value for the LC of the study population was 64%. The HLC group (initial 24 h LC ≥ 64%, n = 333) had a significantly lower incidence of in-hospital death than the LLC group (n = 295) (25.5% in the HLC group vs. 42.7% in the LLC group, p < 0.001). During 12 months of follow-up, the cumulative incidence of all-cause death was significantly lower in the HLC group than in the LLC group (33.0% vs. 48.8%; hazard ratio 0.55; 95% CI 0.42–0.70; p < 0.001). In subgroup analysis, 24 h LC predicted in-hospital mortality better in patients with initial serum lactate > 5 mmol/L than in those with serum lactate ≤ 5 mmol/L (c-statistics of initial serum lactate > 5 mmol/L = 0.782 vs. c-statistics of initial serum lactate ≤ 5 mmol/L = 0.660, p = 0.011).

Conclusions

Higher LC during the early phase of CS was associated with reduced risk of in-hospital and 12 month all-cause mortalities. Patients with LC ≥ 64% during the 24 h after CS onset could expect a favorable prognosis, especially those with an initial serum lactate > 5 mmol/L.

Trial registration: RESCUE (REtrospective and prospective observational Study to investigate Clinical oUtcomes and Efficacy of left ventricular assist device for Korean patients with cardiogenic shock), NCT02985008, Registered December 5, 2016—retrospectively and prospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT02985008

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-021-00571-7.

What Is the Utility of Measuring Lactate Levels in Patients with Sepsis and Septic Shock?

Elevations in blood lactate concentrations have been studied in sepsis and other disease states for decades and are well known to be associated with increased mortality. Many studies have also demonstrated the prognostic accuracy of serial lactate levels, and some have suggested that lactate clearance may be a useful therapeutic target for resuscitation. Lactate measurements have therefore gained an increasingly prominent role in sepsis definitions, screening protocols, management guidelines, and quality measures over the past two decades. The heavy emphasis on lactate monitoring, however, has also generated controversy and concerns. Lactate is not specific to infection and its frequent use for sepsis screening and diagnosis may therefore trigger unnecessary broad-spectrum antibiotic use in some patients. Because hyperlactatemia does not always reflect fluid-responsive hypoperfusion, titrating resuscitation to lactate clearance can also lead to unnecessary fluid and volume overload. More broadly, there is a lack of high-quality evidence demonstrating that initial and serial lactate monitoring leads to better patient-centered outcomes. Indeed, a recent randomized controlled trial comparing resuscitation strategies based on lactate clearance versus normalizing capillary refill time showed no benefit and potential harm with lactate-guided therapy. In this article, we review the basic pathobiology of lactate metabolism and delineate why the traditional paradigm that hyperlactatemia reflects tissue hypoxia is overly simplistic and incomplete. We then review the evidence behind the diagnostic, prognostic, and therapeutic uses of lactate monitoring and place this in the context of evolving sepsis diagnosis and management guidelines.

Prediction of blood lactate values in critically ill patients: a retrospective multi-center cohort study

Elevations in initially obtained serum lactate levels are strong predictors of mortality in critically ill patients. Identifying patients whose serum lactate levels are more likely to increase can alert physicians to intensify care and guide them in the frequency of tending the blood test. We investigate whether machine learning models can predict subsequent serum lactate changes. We investigated serum lactate change prediction using the MIMIC-III and eICU-CRD datasets in internal as well as external validation of the eICU cohort on the MIMIC-III cohort. Three subgroups were defined based on the initial lactate levels: (i) normal group (< 2 mmol/L), (ii) mild group (2-4 mmol/L), and (iii) severe group (> 4 mmol/L). Outcomes were defined based on increase or decrease of serum lactate levels between the groups. We also performed sensitivity analysis by defining the outcome as lactate change of > 10% and furthermore investigated the influence of the time interval between subsequent lactate measurements on predictive performance. The LSTM models were able to predict deterioration of serum lactate values of MIMIC-III patients with an AUC of 0.77 (95% CI 0.762-0.771) for the normal group, 0.77 (95% CI 0.768-0.772) for the mild group, and 0.85 (95% CI 0.840-0.851) for the severe group, with only a slightly lower performance in the external validation. The LSTM demonstrated good discrimination of patients who had deterioration in serum lactate levels. Clinical studies are needed to evaluate whether utilization of a clinical decision support tool based on these results could positively impact decision-making and patient outcomes.

Pharmacometabolomics identifies candidate predictor metabolites of an L-carnitine treatment mortality benefit in septic shock

Sepsis‐induced metabolic dysfunction contributes to organ failure and death. L‐carnitine has shown promise for septic shock, but a recent phase II study of patients with vasopressor‐dependent septic shock demonstrated a non‐significant reduction in mortality. We undertook a pharmacometabolomics study of these patients (n = 250) to identify metabolic profiles predictive of a 90‐day mortality benefit from L‐carnitine. The independent predictive value of each pretreatment metabolite concentration, adjusted for L‐carnitine dose, on 90‐day mortality was determined by logistic regression. A grid‐search analysis maximizing the Z‐statistic from a binomial proportion test identified specific metabolite threshold levels that discriminated L‐carnitine responsive patients. Threshold concentrations were further assessed by hazard ratio and Kaplan‐Meier estimate. Accounting for L‐carnitine treatment and dose, 11 ¹H‐NMR metabolites and 12 acylcarnitines were independent predictors of 90‐day mortality. Based on the grid‐search analysis numerous acylcarnitines and valine were identified as candidate metabolites of drug response. Acetylcarnitine emerged as highly viable for the prediction of an L‐carnitine mortality benefit due to its abundance and biological relevance. Using its most statistically significant threshold concentration, patients with pretreatment acetylcarnitine greater than or equal to 35 µM were less likely to die at 90 days if treated with L‐carnitine (18 g) versus placebo (p = 0.01 by log rank test). Metabolomics also identified independent predictors of 90‐day sepsis mortality. Our proof‐of‐concept approach shows how pharmacometabolomics could be useful for tackling the heterogeneity of sepsis and informing clinical trial design. In addition, metabolomics can help understand mechanisms of sepsis heterogeneity and variable drug response, because sepsis induces alterations in numerous metabolite concentrations.

Evaluation of the Prognostic Value of Lactate and Acid-Base Status in Patients Presenting to the Emergency Department

Background

Lactate levels predict mortality in a wide range of patients presenting to the Emergency Department (ED); however, the effect of co-existing acidosis is unknown. Here, we investigated the effect of acidosis on in-hospital mortality for patients with hyperlactataemia.

Methodology

This is a retrospective cohort study of adults cared for in the resuscitation area of one ED who received a metabolic panel on arrival. The primary outcome was in-hospital mortality for patients with normal lactate (0.0-2.0 mmol/L), intermediate lactate (2.1-4.0 mmol/L), or high lactate (>4.0 mmol/L), with and without acidosis. Odds ratios (ORs) were calculated to assess the differences in mortality rates between groups stratified by lactate and acid-base status.

Results

A total of 4,107 metabolic panels were collected and 3,238 were assessed. In total, 510 (15.8%) and 784 (24.2%) patients had a normal lactate and acidosis/no acidosis; 587 (18.1%) and 842 (26.0%) had intermediate lactate and acidosis/no acidosis; and 388 (12.0%) and 127 (3.9%) had high lactate and acidosis/no acidosis, respectively. The overall mortality was 5%. Mortality was 4.3%/0.6% in the normal lactate, 5.6%/2.6% in the intermediate lactate, and 19.3%/3.9% in the high lactate groups, with and without acidosis, respectively. Combining base excess <-6 and lactate >4 mmol/L had a sensitivity of 39%, specificity of 96%, positive predictive value of 32%, and negative predictive value of 98% for in-hospital mortality (OR: 14.0; 95% confidence interval: 9.77-20.11).

Conclusions

In an undifferentiated cohort of ED patients presenting to the resuscitation area lactaemia associated with acidosis is a more accurate predictor of in-hospital mortality than hyperlactataemia.

Implementation of point-of-care blood gas testing at a large community hospital: Cost analysis, sepsis bundle compliance, and employee engagement

INTRODUCTION/BACKGROUND

Point-of-care testing (POCT) platforms support patient-centered approaches to health care delivery and may improve patient care. We evaluated implementation of a POCT platform at a large, acute care hospital in the Midwestern United States.

METHODS

We used lactate testing as part of a sepsis bundle protocol to evaluate compliance and mortality outcomes. Respiratory team members were surveyed to assess perception of efficiency, ease of use, timely patient care, and overall engagement with the POCT system. Annualized cost per test of a benchtop analyzer and a POCT platform were compared across 3 years for each platform.

RESULTS

Lactate testing volume increased from 61% to 91%, which was associated with improved sepsis bundle protocol compliance. Employees reported high levels of engagement, improvements in efficiency and time savings, and better patient care with POCT. Average cost per test was $10.02 for the benchtop system and $6.21 for the POCT platform. POCT saved our institution $88,476 annually in labor costs.

DISCUSSION

Combined with a robust training program emphasizing the use of lactate testing in the context of the overall clinical picture, POCT enabled adherence to the sepsis bundle protocol and may have contributed to lower mortality. Additionally, the COVID-19 pandemic has provided us with unanticipated benefits of using POCT; it has enhanced our ability to deal with stringent infectious disease protocols, saving time and minimizing patient and staff exposure.

CONCLUSIONS

Implementation of a POCT platform was associated with improved compliance to our sepsis protocol, reduced sepsis mortality, high employee engagement, and cost savings.

The effect of midodrine on lactate clearance in patients with septic shock: a pilot study

Background: The effect of midodrine on lactate clearance has not been assessed in critically ill patients yet. Objective: The goal of this study was to assess the effect of adjunctive midodrine therapy on lactate clearance in patients with septic shock. Materials & methods: Patients with septic shock were assigned to receive either adjunctive midodrine 10 mg three-times a day for 5 days (midodrine group = 15 patients) or not (control group = 13 patients). Results: The lactate clearance was significantly faster in the midodrine group than the control group (p = 0.049) with a large effect size (ηp2 = 0.141). Conclusion: When midodrine was added to intravenous vasopressors, it significantly accelerated lactate clearance in patients with septic shock. Trial registration number: IRCT20100228003449N25 (Clinicaltrials.gov).

Stepwise lactate kinetics in critically ill patients: prognostic, influencing factors, and clinical phenotype

Background

To investigate the optimal target e of lactate kinetics at different time during the resuscitation, the factors that influence whether the kinetics achieve the goals, and the clinical implications of different clinical phenotypes.

Methods

Patients with hyperlactatemia between May 1, 2013 and December 31, 2018 were retrospectively analyzed. Demographic data, basic organ function, hemodynamic parameters at ICU admission (T0) and at 6 h, 12 h, 24 h, 48 h, and 72 h, arterial blood lactate and blood glucose levels, cumulative clinical treatment conditions at different time points and final patient outcomes were collected.

Results

A total of 3298 patients were enrolled, and the mortality rate was 12.2%. The cutoff values of lactate kinetics for prognosis at 6 h, 12 h, 24 h, 48 h, and 72 h were 21%, 40%, 57%, 66%, and 72%. The APACHE II score, SOFA score, heart rate (HR), and blood glucose were risk factors that correlated with whether the lactate kinetics attained the target goal. Based on the pattens of the lactate kinetics, eight clinical phenotypes were proposed. The odds ratios of death for clinical phenotypes VIII, IV, and II were 4.39, 4.2, and 5.27-fold of those of clinical phenotype I, respectively.

Conclusion

Stepwise recovery of lactate kinetics is an important resuscitation target for patients with hyperlactatemia. The APACHE II score, SOFA score, HR, and blood glucose were independent risk factors that influenced achievement of lactate kinetic targets. The cinical phenotypes of stepwise lactate kinetics are closely related to the prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01293-x.

Serum Lactate and A Relative Change in Lactate as Predictors of Mortality in Patients With Cardiogenic Shock - Results from the Cardshock Study

INTRODUCTION

Cardiogenic shock complicating acute myocardial infarction has a very high mortality. Our present study focuses on serial measurement of lactate during admission due to cardiogenic shock and the prognostic effect of lactate and a relative change in lactate in patients after admission and the institution of intensive care treatment.

METHODS AND RESULTS

This is a secondary analysis of the CardShock study. Data on lactate at baseline were available on 217 of 219 patients.In the study population, the median baseline lactate was 2.8 mmol/L (min-max range, 0.5-23.1 mmol/L).At admission, lactate was predictive of 30-day mortality with an adjusted Hazard ratio (HR) of 1.20 mmol/L (95% confidence interval, CI 1.14-1.27). Within the first 24 h of admission, baseline lactate remained predictive of 30-day mortality. Lactate at 6 h had a HR of 1.14 (95% CI 1.06-1.24) and corresponding values at 12 and 24 h had a HR of 1.10 (1.04-1.17), and of HR 1.19 (95% CI 1.07-1.32), respectively. A 50% reduction in lactate within 6 h resulted in a HR of 0.82 (95% CI 0.72-0.94). Corresponding hazard ratios at 12 and 24 h, were 0.87 (95% CI 0.76-0.98) and 0.74 (95% CI 0.60-0.91), respectively.

CONCLUSION

The main findings of the present study are that baseline lactate is a powerful predictor of 30-day mortality, lactate at 6, 12, and 24 h after admission are predictors of 30-day mortality, and a relative change in lactate is a significant predictor of survival within the first 24 h after instituting intensive care treatment adding information beyond the information from baseline values.

Association between normalized lactate load and mortality in patients with septic shock: an analysis of the MIMIC-III database

Background

An index of dynamic lactate change that incorporates both the magnitude of change and the time interval of such change, termed “normalized lactate load,” may reflect the hypoxic burden of septic shock. We aimed to evaluate the association between normalized lactate load and 28-day mortality in adult septic shock patients.

Methods

Patients with septic shock were identified from the Medical Information Mart for Intensive Care (MIMIC)-III database. Lactate load was defined as the sum of the area under the curve (AUC) of serial lactate levels using the trapezoidal rule, and normalized lactate load was defined as the lactate load divided by time. Receiver-operating characteristic curves were constructed to determine the performance of initial lactate, maximum lactate and normalized lactate load in predicting 28-day mortality.

Results

A total of 1371 septic shock patients were included, and the 28-day mortality was 39.8%. Non-survivors had significantly higher initial lactate (means ± standard deviations: 3.9 ± 2.9 vs. 2.8 ± 1.7 mmol/L), maximum lactate (5.8 ± 3.8 vs. 4.3 ± 2.2 mmol/L), lactate load (94.3 ± 71.8 vs. 61.1 ± 36.4 mmol·hr./L) and normalized lactate load (3.9 ± 3.0 vs. 2.5 ± 1.5 mmol/L, all p <  0.001). The AUCs of initial lactate, maximum lactate and normalized lactate load were 0.623 (95% confidence interval: 0.596–0.648, with a cut-off value of 4.4 mmol/L), 0.606 (0.580–0.632, with a cut-off value of 2.6 mmol/L) and 0.681 (0.656–0.706, with a cut-off value of 2.6 mmol/L), respectively. The AUC of normalized lactate load was significantly greater than both initial lactate and maximum lactate (all p <  0.001). In the multivariate logistic regression model, normalized lactate load was identified as an independent risk factor for 28-day mortality.

Conclusions

Normalized lactate load is an independent risk factor for 28-day mortality in adult septic shock patients. Normalized lactate load had better accuracy than both initial and maximum lactate in determining the prognosis of septic shock patients.

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.

Severe Impairment of Microcirculatory Perfused Vessel Density Is Associated With Postoperative Lactate and Acute Organ Injury After Cardiac Surgery

OBJECTIVE

Resuscitation after cardiac surgery needs to address multiple pathophysiological processes that are associated with significant morbidity and mortality. Functional microcirculatory derangements despite normal systemic hemodynamics have been previously described but must be tied to clinical outcomes. The authors hypothesized that microcirculatory dysfunction after cardiac surgery would include impaired capillary blood flow and impaired diffusive capacity and that subjects with the lowest quartile of perfused vessel density would have an increased postoperative lactate level and acute organ injury scores.

DESIGN

Prospective, observational study.

SETTING

A single, tertiary university cardiovascular surgical intensive care unit.

PARTICIPANTS

25 adults undergoing elective cardiac surgery requiring cardiopulmonary bypass.

INTERVENTION

Sublingual microcirculation was imaged using incident dark field microscopy before and 2 to 4 hours after surgery in the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

Compared with baseline measurements, postoperative vessel-by-vessel microvascular flow index (2.9 [2.8-2.9] v 2.5 [2.4-2.7], p < 0.0001) and perfused vessel density were significantly impaired (20.7 [19.3-22.9] v 16.3 [12.8-17.9], p < 0.0001). The lowest quartile of perfused vessel density (<12.8 mm/mm2) was associated with a significantly increased postoperative lactate level (6.0 ± 2.9 v 1.8 ± 1.2, p < 0.05), peak lactate level (7.6 ± 2.8 v 2.8 ± 1.5, p = 0.03), and sequential organ failure assessment (SOFA) score at 24 and 48 hours.

CONCLUSION

In patients undergoing cardiac surgery, there was a significant decrease in postoperative microcirculatory convective blood flow and diffusive capacity during early postoperative resuscitation. Severely impaired perfused vessel density, represented by the lowest quartile of distribution, is significantly related to hyperlactatemia and early organ injury.

Early prediction of in-hospital mortality in acute pancreatitis: a retrospective observational cohort study based on a large multicentre critical care database

OBJECTIVE

To develop and validate a prediction model for predicting in-hospital mortality in patients with acute pancreatitis (AP).

DESIGN

A retrospective observational cohort study based on a large multicentre critical care database.

SETTING

All subject data were collected from the eICU Collaborative Research Database (eICU-CRD), which covers 200 859 intensive care unit admissions of 139 367 patients in 208 US hospitals between 2014 and 2015.

PARTICIPANTS

A total of 746 patients with AP were drawn from eICU-CRD. Due to loss to follow-up (four patients) or incomplete data (364 patients), 378 patients were enrolled in the primary cohort to establish a nomogram model and to conduct internal validation.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcome of the prediction model was in-hospital mortality. All risk factors found significant in the univariate analysis were considered for multivariate analysis to adjust for confounding factors. Then a nomogram model was established. The performance of the nomogram model was evaluated by the concordance index (C-index) and the calibration plot. The nomogram model was internally validated using the bootstrap resampling method. The predictive accuracy of the nomogram model was compared with that of Acute Physiology, Age, and Chronic Health Evaluation (APACHE) IV. Decision curve analysis (DCA) was performed to evaluate and compare the potential net benefit using of different predictive models.

RESULTS

The overall in-hospital mortality rate is 4.447%. Age, BUN (blood urea nitrogen) and lactate (ABL) were the independent risk factors determined by multivariate analysis. The C-index of nomogram model ABL (0.896 (95% CI 0.825 to 0.967)) was similar to that of APACHE IV (p=0.086), showing a comparable discriminating power. Calibration plot demonstrated good agreement between the predicted and the actual in-hospital mortality. DCA showed that the nomogram model ABL was clinically useful.

CONCLUSIONS

Nomogram model ABL, which used readily available data, exhibited high predictive value for predicting in-hospital mortality in AP.

Failure of Lactate Clearance Predicts the Outcome of Critically Ill Septic Patients

Purpose: Early lactate clearance is an important parameter for prognosis assessment and therapy control in sepsis. Patients with a lactate clearance >0% might differ from patients with an inferior clearance in terms of intensive care management and outcomes. This study analyzes a large collective with regards to baseline risk distribution and outcomes. Methods: In total, 3299 patients were included in this analysis, consisting of 1528 (46%) ≤0% and 1771 (54%) >0% patients. The primary endpoint was intensive care unit (ICU) mortality. Multilevel logistic regression analyses were used to compare both groups: A baseline model (model 1) with lactate clearance as a fixed effect and ICU as a random effect was installed. For model 2, patient characteristics (model 2) were included. For model 3, intensive care treatment (mechanical ventilation and vasopressors) was added to the model. Models 1 and 2 were used to evaluate the primary and secondary outcomes, respectively. Model 3 was only used to evaluate the primary outcomes. Adjusted odds ratios (aORs) with respective 95% confidence intervals (CI) were calculated. Results: The cohorts had no relevant differences regarding the gender, BMI, age, heart rate, body temperature, and baseline lactate. Neither the primary infection focuses nor the ethnic background differed between both groups. In both groups, the most common infection sites were of pulmonary origin, the urinary tract, and the gastrointestinal tract. Patients with lactate clearance >0% evidenced lower sepsis-related organ failure assessment (SOFA) scores (7 ± 6 versus 9 ± 6; p < 0.001) and creatinine (1.53 ± 1.49 versus 1.80 ± 1.67; p < 0.001). The ICU mortality differed significantly (14% versus 32%), and remained this way after multivariable adjustment for patient characteristics and intensive care treatment (aOR 0.43 95% CI 0.36–0.53; p < 0.001). In the additional sensitivity analysis, the lack of lactate clearance was associated with a worse prognosis in each subgroup. Conclusion: In this large collective of septic patients, the 6 h lactate clearance is an independent method for outcome prediction.

Prognostic value of plasma pentraxin 3 levels in patients with septic shock admitted to intensive care

Objective

To evaluate the usefulness of a new marker, pentraxin, as a prognostic marker in septic shock patients.

Materials and methods

Single-centre prospective observational study that included all consecutive patients 18 years or older who were admitted to the intensive care unit (ICU) with septic shock. Serum levels of procalcitonin (PCT), C-reactive protein (CRP) and pentraxin (PTX3) were measured on ICU admission.

Results

Seventy-five septic shock patients were included in the study. The best predictors of in-hospital mortality were the severity scores: SAPS II (AUC = 0.81), SOFA (AUC = 0.79) and APACHE II (AUC = 0.73). The ROC curve for PTX3 (ng/mL) yielded an AUC of 0.70, higher than the AUC for PCT (0.43) and CRP (0.48), but lower than lactate (0.79). Adding PTX3 to the logistic model increased the predictive capacity in relation to SAPS II, SOFA and APACHE II for in-hospital mortality (AUC 0.814, 0.795, and 0.741, respectively). In crude regression models, significant associations were found between in-hospital mortality and PTX3. This positive association increased after adjusting for age, sex and immunosuppression: adjusted OR T3 for PTX3 = 7.83, 95% CI 1.35–45.49, linear P trend = 0.024.

Conclusion

Our results support the prognostic value of a single determination of plasma PTX3 as a predictor of hospital mortality in septic shock patients.

Prehospital lactate clearance is associated with reduced mortality in patients with septic shock

BACKGROUND

Assessment of disease severity in patients with septic shock (SS) is crucial in determining optimal level of care. In both pre- and in-hospital settings, blood lactate measurement is broadly used in combination with the clinical evaluation of patients as the clinical picture alone is not sufficient for assessing disease severity and outcomes.

METHODS

From 15th April 2017 to 15th April 2019, patients with SS requiring prehospital mobile Intensive Care Unit intervention (mICU) were prospectively included in this observational study. Prehospital blood lactate clearance was estimated by the difference between prehospital (time of first contact between the patients and the mICU prior to any treatment) and in-hospital (at hospital admission) blood lactate levels divided by prehospital blood lactate.

RESULTS

Among the 185 patients included in this study, lactate measurement was missing for six (3%) in the prehospital setting and for four (2%) at hospital admission, thus 175 (95%) were analysed for prehospital blood lactate clearance (mean age 70 ± 14 years). Pulmonary, digestive and urinary infections were probably the cause of the SS in respectively 56%, 22% and 10% of the cases. The 30-day overall mortality was 32%. Mean prehospital blood lactate clearance was significantly different between patients who died and those who survived (respectively 0.41 ± 2.50 mmol.l^-1 vs 1.65 ± 2.88 mmol.l^-1, p = 0.007). Cox regression analysis showed that 30-day mortality was associated with prehospital blood lactate clearance > 10% (HRa [CI95] = 0.49 [0.26-0.92], p = 0.028) and prehospital blood lactate clearance < 10% (HRa [CI95] = 2.04 [1.08-3.84], p = 0.028).

CONCLUSION

A prehospital blood lactate clearance < 10% is associated with 30-day mortality increase in patients with SS handled by the prehospital mICU. Further studies will be needed to evaluate if prehospital blood lactate clearance alone or combined with clinical scores could affected the triage decision-making process for those patients.

Lactate levels and clearance rate in neonates undergoing mechanical ventilation in Tibet

Objective

This study aimed to examine the characteristics of blood lactate in neonates undergoing mechanical ventilation in Tibet.

Methods

We recruited 67 neonates undergoing mechanical ventilation in Naqu People’s Hospital as the plateau observation group and 94 neonates undergoing mechanical ventilation in Shengjing Hospital as the control group. We analyzed the differences in lactate levels between the two groups.

Results

The lactate clearance rates of neonates with asphyxia and those with respiratory distress syndrome were significantly lower in the plateau group than in the control group. Lactate levels in neonates who died in the plateau group were significantly higher and the lactate clearance rate was significantly lower than those in neonates who survived. The cut-off point for the lactate clearance rate at 6 hours for predicting mortality was 6.09% in the plateau group.

Conclusion

The lactate clearance rate of neonates on mechanical ventilation in the plateau area is lower than that in neonates in the non-plateau area. The lactate clearance rate at 6 hours is important for evaluating the prognoses of critical neonates in plateau areas.

Early lactate measurements for predicting in-hospital mortality in paediatric sepsis

AIM

We compared the performance of plasma lactate with high-sensitivity C-reactive protein (hs-CRP), and paediatric sepsis-related organ failure assessment (pSOFA) score for predicting mortality in septic children.

METHODS

Serial plasma lactate and hs-CRP levels and pSOFA score was assessed during early hospital stay in septic children.

RESULTS

Out of 149 participants, 45 died. Plasma lactate at 0 h and 6 h was significantly higher, and lactate clearance was significantly lower in non-survivors. The optimal cut-off of plasma lactate at 6h for identifying mortality was 2.5 mmol/L (sensitivity 85% and specificity 74%). pSOFA score had the best predictive ability for mortality (AUC 0.89) followed by hs-CRP at 0 h (AUC 0.86), hs-CRP at 48 h (AUC 0.83), plasma lactate levels at 6 h (AUC 0.83), and plasma lactate at 0 h (AUC 0.67).

CONCLUSION

pSOFA score, hs-CRP and hyperlactemia at 6 h can identify septic children at risk of dying.

Arterial lactate in traumatic brain injury - Relation to intracranial pressure dynamics, cerebral energy metabolism and clinical outcome

PURPOSE

High arterial lactate is associated with disturbed systemic physiology. Lactate can also be used as alternative cerebral fuel and it is involved in regulating cerebral blood flow. This study explored the relation of endogenous arterial lactate to systemic physiology, pressure autoregulation, cerebral energy metabolism, and clinical outcome in traumatic brain injury (TBI).

METHOD

A retrospective study including 115 patients (consent given) with severe TBI treated in the neurointensive care unit, Uppsala university hospital, Sweden, 2008-2018. Data from cerebral microdialysis, arterial blood gases, hemodynamics and intracranial pressure were analyzed the first ten days post-injury.

RESULTS

Arterial lactate peaked on day 1 post-injury (mean 1.7 ± 0.7 mM) and gradually decreased. Higher arterial lactate correlated with lower age (p-value < 0.05), higher Marshall score (p-value < 0.05) and higher arterial glucose (p-value < 0.001) in a multiple regression analysis. Higher arterial lactate was associated with poor pressure autoregulation (p-value < 0.01), but not to worse cerebral energy metabolism. Higher arterial lactate was also associated with unfavorable clinical outcome (p-value < 0.05).

CONCLUSIONS

High endogenous arterial lactate is a biomarker of poor systemic physiology and may disturb cerebral blood flow autoregulation.

Lactate/albumin ratio: An early prognostic marker in critically ill patients

OBJECTIVES

We investigate the clinical utility of the lactate/albumin (L/A) ratio as an early prognostic marker of ICU mortality in a large cohort of unselected critically ill patients.

METHODS

A retrospective single-center study using data from the Multiparameter Intelligent Monitoring Intensive Care III (MIMIC-III) database collected between 2001 and 2012. We screened adult patients (age ≥ 15) with measured lactate and albumin on the first day of ICU stay to evaluate the prognostic performance of the lactate and lactate/albumin (L/A) ratio for ICU mortality prediction.

RESULTS

The overall ICU mortality in the 6414 eligible ICU patients was 16.4%. L/A showed a receiver-operating characteristics area under the curve (ROC-AUC) value of 0.69 (95% CI: 0.67, 0.70) to predict ICU mortality, higher than lactate 0.67 (95%CI: 0.65, 0.69). Regardless of the lactate level, L/A yielded better ROC-AUC compared to the lactate level [normal lactate (<2.0 mmol/L): 0.63 vs 0.60; intermediate lactate (2.0 mmol/L ≤ lactate <4.0 mmol/L): 0.58 vs 0.56; high lactate (≥4.0 mmol/L): 0.67 vs 0.66]. L/A was a better prognostic marker for ICU mortality in patients with decreased lactate elimination [hepatic dysfunction: 0.72 vs 0.70; renal dysfunction 0.70 vs 0.68]. The L/A ratio ROC-AUC was better in patients with sepsis (0.68 vs 0.66) and those who developed severe sepsis or septic shock (0.68 vs 0.66).

CONCLUSIONS

The performance of L/A and lactate were equivalent in predicting ICU mortality and can be used as early prognostic markers for ICU patients with different initial lactate level and the presence of hepatic or renal dysfunction.

Biomarkers and newer laboratory investigations in the diagnosis of sepsis

Sepsis is a major cause of death in hospitalised patients accounting for mortality rates as high as 60% and, hence, is called 'a hidden public health disaster'. Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis is not a disease but is a clinical syndrome, where the initial features are nonspecific resulting in delayed diagnosis. Lack of specific laboratory tests to diagnose the syndrome adds to the diagnostic confusion. Failure to identify sepsis in the early stages itself delays effective treatment resulting in high morbidity and mortality. Various biomarkers and newer laboratory tests help to address these issues. However, to date there is no ideal test to diagnose sepsis. The most commonly used markers are C-reactive protein (CRP) and procalcitonin (PCT). There are around 180 biomarkers reported to be useful in sepsis. In addition to CRP and PCT, various emerging laboratory markers, such as like serum amyloid A, soluble triggering receptor expressed on myeloid cell-1, mannan and antimannan antibodies, and interferon γ inducible protein-10 etc., have been reviewed and their clinical usefulness discussed in this paper.

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.

Septic shock in pediatrics: the state-of-the-art

OBJECTIVE

Review the main aspects of the definition, diagnosis, and management of pediatric patients with sepsis and septic shock.

SOURCE OF DATA

A search was carried out in the MEDLINE and Embase databases. The articles were chosen according to the authors' interest, prioritizing those published in the last five years.

SYNTHESIS OF DATA

Sepsis remains a major cause of mortality in pediatric patients. The variability of clinical presentations makes it difficult to attain a precise definition in pediatrics. Airway stabilization with adequate oxygenation and ventilation if necessary, initial volume resuscitation, antibiotic administration, and cardiovascular support are the basis of sepsis treatment. In resource-poor settings, attention should be paid to the risks of fluid overload when administrating fluids. Administration of vasoactive drugs such as epinephrine or norepinephrine is necessary in the absence of volume response within the first hour. Follow-up of shock treatment should adhere to targets such as restoring vital and clinical signs of shock and controlling the focus of infection. A multimodal evaluation with bedside ultrasound for management after the first hours is recommended. In refractory shock, attention should be given to situations such as cardiac tamponade, hypothyroidism, adrenal insufficiency, abdominal catastrophe, and focus of uncontrolled infection.

CONCLUSIONS

The implementation of protocols and advanced technologies have reduced sepsis mortality. In resource-poor settings, good practices such as early sepsis identification, antibiotic administration, and careful fluid infusion are the cornerstones of sepsis management.

Early variation of quick sequential organ failure assessment score to predict in-hospital mortality in emergency department patients with suspected infection

BACKGROUND

The quick sequential organ failure assessment (qSOFA) score showed good prognostic performance in patients with suspicion of infection in the emergency department (ED). However, previous studies only assessed the performance of individual values of qSOFA during the ED stay. As this score may vary over short timeframes, the optimal time of measurement, and the prognostic value of its variation are unclear. The objective of the present study was to prospectively assess the prognostic value of the change in qSOFA over the first 3 h (ΔqSOFA = qSOFA at 3 h-qSOFA at inclusion).

PATIENTS AND METHODS

This is an international prospective cohort study conducted in 17 EDs in France, Belgium, and Spain. From November 2016 to March 2017, patients with a suspected infection and a qSOFA score of 2 or higher were included and followed up until death or hospital discharge. qSOFA was measured at inclusion, 1 h and 3 h. Primary end point was in-hospital mortality, truncated at 28 days.

RESULTS

Of 534 recruited patients, 512 were included in the analysis. The qSOFA was improved at 3 h (ΔqSOFA < 0) in 287 (55%) patients. Overall in-hospital mortality was 27%: 44% when ΔqSOFA greater than 0, 36% when ΔqSOFA = 0, and 18% when ΔqSOFA less than 0. A positive ΔqSOFA was independently associated with reduced in-hospital mortality (adjusted hazard ratio of 0.48, 95% confidence interval: 0.34-0.68). After modeling qSOFA kinetics in the first 3 h, there was a significant difference in adjusted slopes between patients who died and those who survived (0.15, 95% confidence interval: 0.09-0.22, P < 0.001).

CONCLUSION

In patients with suspected infection presenting to the ED with a qSOFA of 2 or higher, the early change in qSOFA is a strong independent predictor of mortality.

The utility of point of care serum lactate in predicting serious adverse outcomes among critically ill adult patients at urban emergency departments of tertiary hospitals in Tanzania

Background

Elevated serum lactate levels have been shown in numerous studies to be associated with serious adverse events, including mortality. Point of care lactate level is increasingly available in resource-limited emergency department (ED) settings. However, little is known about the predictive ability of for serious adverse events.

Aim of the study

We aimed to describe the utility of serum lactate level as a predictor of 24-h serious adverse events among adult patients presenting at the Emergency Medicine Department (EMD) of Muhimbili National Hospital (MNH) and MUHAS Academic Medical Center (MAMC).

Methods

This was a prospective observational study involving adult patients presenting to the EMD-MNH and MAMC from 1 September 2018 and 31 October 2018. Eligible patients with at least one lactate level test drawn while in the ED were examined in terms of their demographics, relevant clinical characteristics, and any serious adverse event (SAE) within 24 h of arrival. The sensitivity and specificity of lactate level to predict outcomes of interest were determined using the best cut-off point constructed from AUROC to see how well lactate level could discriminate which patients would have adverse events in the next 24 h. Categorical and continuous variables were compared with the chi-square test and two-sample t test, respectively.

Results

We screened 2057 (20.9%) out of 9828 patients who presented during study period, and enrolled 387 (18.8%). The overall median age was 54 years (interquartile range 40–68 years) and 206 (53.2%) were male. Using local triaging system, a total of 322 (83.2%) was triaged as an emergency category. The mean lactate level was 3.2 ± 3.6 mmol/L, 65 (16.8%) patients developed at least one SAE, with 42 (11%) who required ICU/HDU, 37 (10%) needed ventilator support, 10 (3%) required inotropes, and 9 (2%) developed cardiac arrest. The overall 24-h mortality was 28 (7%). The AUC of serum lactate level for overall 24-h mortality was 0.801 (95%CI, 0.7–0.9, P ≤ 0.001). At the optimal cutoff value (3.8 mmol/L), lactate level had a sensitivity and specificity for 24-h mortality of 64% and 85%, respectively. Mortality of the high-lactate level group (³3.8 mmol/L) was significantly higher than that of the low-lactate level group (< 3.8 mmol/L), 23.8% vs. 2.9%, respectively (95%CI 3.8–17.2, p < 0.001), with the relative risk of mortality in the high-lactate level group being 8.1 times higher compared to the low-lactate level group.

Conclusion

The utility of lactate level in predicting mortality was similar to that seen in high-resource settings. A serum lactate level of ³3.8 mmol/L predicted 24-h serious adverse events in unselected patients seen in the high-acuity area of our ED. Incorporating serum lactate level in ED in lower- and middle-income countries (LMICs) can help identify patients at risk of developing serious adverse events.