Early hyperlactataemia in critically ill children

Lactate, an Essential Metabolic Marker in the Diagnosis and Management of Pediatric Conditions

Measurement of circulating lactate is an essential diagnostic tool in pediatric medicine, playing a crucial role in assessing metabolic status and tissue oxygenation. Initially regarded as a byproduct of anaerobic metabolism, recent research has expanded our understanding of lactate's roles across various physiological systems, from energy metabolism to immune modulation and neurological health. Elevated lactate levels are widely utilized to monitor critical conditions such as sepsis, trauma, and hypoxic-ischemic injury, offering valuable prognostic information in intensive care settings. Notably, lactate dynamics-particularly trends in serial measurements-are more effective than single readings for predicting clinical outcomes, especially in sepsis and trauma. Measurement of circulating lactate in different body fluids (blood, cerebrospinal fluid, and umbilical blood) provides critical insights into neonatal health and central nervous system involvement. However, challenges remain, including the need for non-invasive and rapid point-of-care testing, particularly in neonatal populations. Our aim was to review and synthesize the current literature on the role and particularities of measurement of circulating lactate in pediatric pathology. Emerging technologies, such as machine learning models and small molecule inhibitors, show promise in advancing lactate regulation and predicting hemodynamic instability. As the role of lactate in pediatric pathology continues to evolve, optimizing measurement protocols and exploring new therapeutic strategies will enhance early detection, intervention, and clinical outcomes for critically ill children.

Hyperlactataemia Following Crystalloid Cardiopulmonary Bypass Priming in Paediatric Cardiac Surgery-Benign or Malignant? A Retrospective Study

BACKGROUND

Various mechanisms leading to early hyperlactataemia post-cardiac surgery have been postulated. Specifically, in the paediatric population, benign early hyperlactataemia may be associated with crystalloid priming in the cardiopulmonary bypass circuit. The aim of this study was to review paediatric patients who had crystalloid prime and assess their outcomes.

METHODS

A retrospective review of paediatric patients who underwent cardiac surgery with crystalloid prime at our institution between November 2014 and May 2018 was performed. Data were collected from medical and laboratory records.

RESULTS

Among 569 patients, 237 (42%) received a crystalloid prime; 51 (22%) were excluded due to intraoperative hyperlactataemia. Of the remaining 186 patients, 98 (53%) developed hyperlactataemia postoperatively. Patients with hyperlactataemia had longer cardiopulmonary bypass and aortic cross-clamp times but similar Aristotle complexity scores. Patients with postoperative hyperlactataemia had higher peak VIS [median 8 (IQR 0-8) vs. 5 (IQR 0-8)] within the first 24 h (p = 0.002). However, there was no difference in the duration of ventilation between the two groups (p = 0.14). Yet only 58% of patients with hyperlactataemia were discharged from the ICU within 24 h, compared to 78% without hyperlactataemia.

CONCLUSIONS

In this study population, transient postoperative hyperlactataemia in paediatric patients with crystalloid prime may not necessarily indicate tissue hypoxaemia. Despite a similar duration of ventilation in patients with and without hyperlactataemia, patients with hyperlactataemia had a longer duration of inotropes and ICU stay. Consideration should be given to discontinuing inotropes in patients with crystalloid prime and postoperative early hyperlactataemia once they are extubated.

Prognostic values of serum lactate-to-bicarbonate ratio and lactate for predicting 28-day in-hospital mortality in children with dengue shock syndrome

This study aimed to assess the clinical utility of blood lactate-to-bicarbonate (L/B) ratio, as a prognostic factor for 28-day in-hospital mortality in children with dengue shock syndrome (DSS), admitted to the pediatric intensive care unit (PICU). This single-center retrospective study was conducted at a tertiary children hospital in southern Vietnam from 2013 to mid-2022. Prognostic models for DSS mortality were developed, using a predefined set of covariates in the first 24 hours of PICU admission. Area under the curves (AUCs), multivariable logistic and Least Absolute Shrinkage and Selection Operator (LASSO) regressions, bootstrapping and calibration slope were performed. A total of 492 children with DSS and complete clinical and biomarker data were included in the analysis, and 26 (5.3%) patients died. The predictive values for DSS mortality, regarding lactate showing AUC 0.876 (95% CI, 0.807-0.944), and that of L/B ratio 0.867 (95% CI, 0.80-0.934) (P values of both biomarkers < .001). The optimal cutoff point of the L/B ratio was 0.25, while that of lactate was 4.2 mmol/L. The multivariable model showed significant clinical predictors of DSS fatality including severe bleeding, cumulative amount of fluid infused and vasoactive-inotropic score (>30) in the first 24 hours of PICU admission. Combined with the identified clinical predictors, the L/B ratio yielded higher prognostic values (odds ratio [OR] = 8.66, 95% confidence interval [CI], 1.96-38.3; P < .01) than the lactate-based model (OR = 1.35, 95% CI, 1.15-1.58; P < .001). Both the L/B and lactate models showed similarly good performances. Considering that the L/B ratio has a better prognostic value than the lactate model, it may be considered a potential prognostic biomarker in clinical use for predicting 28-day mortality in PICU-admitted children with DSS.

Post hospital admission blood lactate measurements are associated with mortality but not neurologic morbidity in children with cerebral malaria

BACKGROUND

In children with cerebral malaria (CM) admission blood lactate has previously guided intravenous fluid therapy and been validated as a prognostic biomarker associated with death. The usefulness of post-admission measurements of blood lactate in children with CM is less clear. The strength of association between blood lactate and neurological sequelae in CM survivors, as well as the optimal duration of post-admission measurements of blood lactate to identify children at higher risk of adverse outcomes is unknown.

METHODS

A retrospective cohort study of 1674 Malawian children with CM hospitalized from 2000 to 2018 who had blood lactate measurements every 6 h for the first 24 h after admission was performed. The strength of association between admission lactate or values measured at any time point in the first 24 h post-admission and outcomes (mortality and neurological morbidity in survivors) was estimated. The duration of time after admission that lactate remained a valid prognostic biomarker was assessed.

RESULTS

When lactate is analysed as a continuous variable, children with CM who have higher values at admission have a 1.05-fold higher odds (95% CI 0.99-1.11) of death compared to those with lower lactate values. Children with higher blood lactate at 6 h have 1.16-fold higher odds (95% CI 1.09-1.23) of death, compared to those with lower values. If lactate levels are dichotomized into hyperlactataemic (lactate > 5.0 mmol/L) or not, the strength of association between admission lactate and mortality increases (OR = 2.49, 95% CI 1.47-4.22). Blood lactate levels obtained after 18 h post-admission are not associated with outcomes. Similarly, the change in lactate concentrations through time during the first 24 h of hospital admission is not associated with outcomes. Blood lactate during hospitalization is not associated with adverse neurologic outcomes in CM survivors.

CONCLUSIONS

In children with CM, blood lactate is associated with death but not neurologic morbidity in survivors. To comprehensively estimate prognosis, blood lactate in children with CM should be assessed at admission and for 18 h afterwards.

Association between Serum Lactate and Morbidity and Mortality in Neonates: A Systematic Review and Meta-Analysis

OBJECTIVE

Lactate is a marker of hypoperfusion in critically ill patients. Whether lactate is useful for identifying and stratifying neonates with a higher risk of adverse outcomes remains unknown. This study aimed to investigate the association between lactate and morbidity and mortality in neonates.

METHODS

A meta-analysis was performed to determine the association between blood lactate levels and outcomes in neonates. Ovid MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov were searched from inception to 1 May 2021. A total of 49 observational studies and 14 data accuracy test studies were included. The risk of bias was assessed using the Newcastle-Ottawa Scale for observational studies and the QUADAS-2 tool for data accuracy test studies. The primary outcome was mortality, while the secondary outcomes included acute kidney injury, necessity for renal replacement therapy, neurological outcomes, respiratory morbidities, hemodynamic instability, and retinopathy of prematurity.

RESULTS

Of the 3184 articles screened, 63 studies fulfilled all eligibility criteria, comprising 46,069 neonates. Higher lactate levels are associated with mortality (standard mean difference, -1.09 [95% CI, -1.46 to -0.73]). Using the estimated sensitivity (0.769) and specificity (0.791) and assuming a prevalence of 15% for adverse outcomes (median of prevalence among studies) in a hypothetical cohort of 10,000 neonates, assessing the lactate level alone would miss 346 (3.46%) cases (false negative) and wrongly diagnose 1776 (17.76%) cases (false positive).

CONCLUSIONS

Higher lactate levels are associated with a greater risk of mortality and morbidities in neonates. However, our results do not support the use of lactate as a screening test to identify adverse outcomes in newborns. Research efforts should focus on analyzing serial lactate measurements, rather than a single measurement.

Can lactate be valuable in early diagnosis and prognosis of neonatal sepsis?

Background

Sepsis monitoring tissue perfusion is crucial for detecting circulatory failure early, implementing the right treatments, and assessing response. Insufficient oxygenation leads to a rise in lactate level and has been shown to be useful in predicting mortality and morbidity in newborns. There have not been many studies on how lactate measurement affects neonatal sepsis diagnosis and prognosis.

Aim

The aim of our study was to determine the impact of lactate on early diagnosis and prognosis in neonatal sepsis.

Materials and Methods

Eighty-seven newborns diagnosed with neonatal sepsis at a neonatal intensive care unit between January 2010 and July 2021 were included in the study. Venous blood gas, lactate, and C-reactive protein (CRP) levels and complete blood count on the first, second, and third day of hospitalization were noted. Lactate values were correlated with other variables to determine the impact of hyperlactatemia on morbidity and to determine factors affecting the length of stay. IBM SPSS Statistics version 22.0 for Windows was used to analyze the data (SPSS Inc., Chicago, IL, United States).

Results

A strong negative correlation between lactate and oxygenation and perfusion indicators (HCO3, BE, PaO2) during the therapeutic process was observed. With treatment, the initial measured lactate value decreased, and a significant increase in CRP and oxygen saturation was observed, which was interpreted as the observation of an early lactate response to infection before a CRP response. The initial lactate level, as well as the change in lactate levels, was not, however, significantly correlated with the length of stay.

Conclusion

Lactate can be used in the early diagnosis of neonatal sepsis and for determining prognosis.

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

BACKGROUND

Hyperlactatemia is a common finding in critically ill patients and has significant prognostic implications. However, a single lactate measurement has not been correlated to mortality consistently. In this study, we aimed to correlate the clinical efficacy of lactate clearance for the prediction of mortality in pediatric intensive care unit patients.

METHODS

This retrospective observational study was performed in the pediatric intensive care unit in patients with lactate level >3 mmol/lt. Initial, 6th h, and 24th h lactate levels were recorded and lactate clearance was calculated using these values (lactate level at admission - level 6 h later × 100/lactate level at admission).

RESULTS

A total of 172 patients were included in the study. Forty-four out of 172 patients died. Median (IQR) lactate (mmol/L) at admission was low in those who survived in comparison to nonsurvivors 4.4 (3.1) vs. 5.75 (7.7) (p = 0.002). Clearance at 6th h was significantly lower in those who died (11.7%) than those who survived (36.7) (p = 0.001). 6th h lactate clearance level <20.7% predicted mortality with a sensitivity of 63.6% and specificity of 69.5% along with a positive predictive value of 41.8 and a negative predictive value of 84.8 (p = 0.004). Both lactate levels and lactate clearance values were significantly predictive factors for mortality (p < 0.05). Only a positive moderate correlation was found between the percentage of PRISM-IV % and 6th h lactate level.

DISCUSSION

The present study revealed that lactate clearance is a simple and rapid risk-stratification tool holding to be a potential biomarker of managing the treatment efficacy of children in the pediatric intensive care unit.

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.

Is Serum Lactate a Good Predictor of Mortality in Children Aged 2 Months to 5 Years With Pneumonia in Central Vietnam

Pneumonia is a major cause of morbidity and mortality in children globally. Lactate, a product of anaerobic cellular metabolism, has been used as an indicator of poor tissue oxygenation and cellular hypoxia. Our objective was to determine whether serum lactate concentration at hospital admission predicted mortality in children aged 2 months to 5 years with pneumonia. Two hundred and eighty-one pediatric patients admitted to the Department of Pediatrics of a provincial hospital with WHO-defined pneumonia and severe pneumonia were included; of whom, 8 died during hospital stay. The median serum lactate concentration was 4.8 mmol/l (IQR 2.6-6.9) among children who died and 3.6 mmol/l (IQR 2.8-4.3) among children who survived (P > .05); 4.1 mmol/l (IQR 2.7-4.7) among children with severe pneumonia and 3.5 mmol/l (IQR 2.8-4.3) among children with pneumonia (P > .05). Serum lactate concentration had a low value in predicting pneumonia-related mortality (AUC 0.68, 95% CI 0.62-0.73); and the concentration cut-off of >4.06 mmol/l had the best sensitivity and specificity (75% and 68.9%, respectively) with a 2.4-fold risk of death (LR+ 2.4; 95% CI 1.6-3.7). Although hyperlactatemia was associated with severity and mortality in children 2 months to 5 years of age with pneumonia, its benefit was unclear.

How to interpret lactate

The association between hyperlactataemia and poorer outcomes in acutely unwell adults and children is well recognised. Blood lactate testing has become readily available in acute settings and is considered a first-line investigation in international guidelines for the management of sepsis. However, while healthcare professionals do appreciate the value of measuring blood lactate in acute severe illness, its clinical significance and interpretation remain less well understood. In this paper, we present the evidence for the use of lactate as a diagnostic test and prognostic marker in acutely unwell children.

Recommendations for hemodynamic monitoring for critically ill children-expert consensus statement issued by the cardiovascular dynamics section of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC)

BACKGROUND

Cardiovascular instability is common in critically ill children. There is a scarcity of published high-quality studies to develop meaningful evidence-based hemodynamic monitoring guidelines and hence, with the exception of management of shock, currently there are no published guidelines for hemodynamic monitoring in children. The European Society of Paediatric and Neonatal Intensive Care (ESPNIC) Cardiovascular Dynamics section aimed to provide expert consensus recommendations on hemodynamic monitoring in critically ill children.

METHODS

Creation of a panel of experts in cardiovascular hemodynamic assessment and hemodynamic monitoring and review of relevant literature-a literature search was performed, and recommendations were developed through discussions managed following a Quaker-based consensus technique and evaluating appropriateness using a modified blind RAND/UCLA voting method. The AGREE statement was followed to prepare this document.

RESULTS

Of 100 suggested recommendations across 12 subgroups concerning hemodynamic monitoring in critically ill children, 72 reached "strong agreement," 20 "weak agreement," and 2 had "no agreement." Six statements were considered as redundant after rephrasing of statements following the first round of voting. The agreed 72 recommendations were then coalesced into 36 detailing four key areas of hemodynamic monitoring in the main manuscript. Due to a lack of published evidence to develop evidence-based guidelines, most of the recommendations are based upon expert consensus.

CONCLUSIONS

These expert consensus-based recommendations may be used to guide clinical practice for hemodynamic monitoring in critically ill children, and they may serve as a basis for highlighting gaps in the knowledge base to guide further research in hemodynamic monitoring.

Blood L-Lactate Concentration as an Indicator of Outcome in Roe Deer (Capreolus capreolus) Admitted to a Wildlife Rescue Center

Simple Summary

Roe deer are among the most frequent wild animals admitted to rescue centers in Italy. Reasons for admission include trauma, predation, starvation, and imprinting, with the final aim of hospitalization being full recovery and release into the wild for all cases. An accurate triage procedure is vital for predicting the outcome, to avoid unnecessary time spent in captivity, and an excessive allocation of time and resources on animals with a minimal chance of recovery. Since lactacidosis is often associated with death in hospitalized animals, and has been associated with poor prognosis in humans and domestic animals, we proposed an evaluation of blood L-lactate using a rapid whole blood test in order to predict the outcome of hospitalized roe deer. A cut-off of 10.2 mmol/L was identified as the best, in order distinguish animals with minimal chance of surviving and release. For these animals, humane euthanasia should be considered as an option.

Abstract

Roe deer (Capreolus capreolus) are among the most frequent patients of rescue centers in Italy. Three outcomes are possible: natural death, euthanasia, or treatment and release. The aim of the present study is to propose blood L-lactate concentration as a possible prognostic biomarker that may assist veterinarians in the decision-making process. Sixty-three roe deer, admitted to one rescue center in the period between July 2018 and July 2019, were sampled and divided into 4 groups according to their outcome: (1) spontaneous death (17 cases), (2) humanely euthanized (13 cases), (3) fully recovered and released (13 cases), and (4) euthanized being unsuitable for release (20 cases). In addition, blood samples from 14 hunted roe deer were analyzed as controls. Whole blood lactate concentrations were measured with a point of care lactate meter. Differences among groups were close to statistical significance (p = 0.51). A cut-off value of 10.2 mmol/L was identified: all the animals with higher values died or were humanely euthanized. The results suggest that roe deer with lactatemia higher than 10.2 mmol/L at admission, have a reduced prognosis for survival during the rehabilitation period, regardless of the reason for hospitalization and the injuries reported. Therefore, humane euthanasia should be considered for these animals.

Plasma lactate can improve the accuracy of the Pediatric Sequential Organ Failure Assessment Score for prediction of mortality in critically ill children: A pilot study

BACKGROUND

Plasma lactate has been used to predict the prognosis of critically ill children, but mortality risk scores appear to be more appealing, particularly in resource-limited countries.

OBJECTIVE

To assess the prognostic utility of lactate compared with the pediatric Sequential Organ Failure Assessment (pSOFA) score among the general pediatric intensive care unit (PICU) population.

METHODS

This was a prospective observational study including 78 children admitted to a tertiary-level PICU. Plasma lactate was measured upon admission and repeated 24h later. pSOFA score, Pediatric Risk of Mortality, and Pediatric Index of Mortality-2 (PIM2) were calculated. The primary outcome was 30-day mortality.

RESULTS

In total, 47.4% of patients had hyperlactatemia at admission. Among these, 20.5% had persistent hyperlactatemia. No significant difference in admission lactate level was found between survivors and nonsurvivors. The 24-h, peak, and average lactate levels were higher among nonsurvivors (P=0.005, 0.035, and 0.019, respectively). The 24-h lactate level and pSOFA score were independent predictors of mortality (adjusted odds ratio and 95% confidence interval=1.12 [1.02-1.23] and 1.80 [1.23-2.64], respectively]. The 24-h lactate level showed positive correlations with pSOFA, PRISM, and PIM2 (Spearman correlation coefficient=0.31, 0.23, 0.43; P=0.006, P=0.047, P<0.001, respectively). The 24-h lactate level had an area under the receiver operating characteristic curve (AUC) of 0.77 (P=0.013) for mortality prediction, while admission, peak, and average lactate level had an AUC of 0.69, 0.69, 0.71 (P=0.086, P=0.035, P=0.019), respectively. PIM2, PRISM, and pSOFA score had an AUC of 0.80, 0.78, 0.82 (P=0.001, P=0.001, and P<0.001), respectively. Combining 24-h lactate level with pSOFA demonstrated superior performance (AUC=0.88).

CONCLUSION

Both 24-h lactate level and pSOAF are useful for prediction of mortality. Incorporating the 24-h lactate level into the pSOFA Score achieved superior prognostic utility.

Evaluation of the Association of Early Elevated Lactate With Outcomes in Children With Severe Sepsis or Septic Shock

OBJECTIVE

The aim of the study was to assess the association of initial lactate (L0) with mortality in children with severe sepsis.

METHODS

This prospective cohort study included 74 patients younger than 18 years with severe sepsis admitted to the pediatric intensive care unit (PICU) of a tertiary, academic children's hospital with lactate measured within 3 hours of meeting severe sepsis or septic shock. The primary outcome was in-hospital mortality. The secondary outcomes included PICU and hospital length of stay.

RESULTS

Although overall mortality was 10.5% (n = 18), patients with L0 measured (n = 72) had a higher mortality (16% vs 6%, P = 0.03) and higher median PRISM-III risk of mortality scores (P = 0.02) than those who did not. Median L0 was no different between nonsurvivors and survivors (3.6 mmol/L [interquartile range, 2.0-9.0] in nonsurvivors vs 2.3 mmol/L [interquartile range, 1.4-3.5] in survivors, P = 0.11). However, L0 was independently associated with PRISM-III score (coefficient, 1.12; 95% confidence interval, 0.4-1.8; P = 0.003) with an increase in mean PRISM-III score of 1.12 U for every 1 mmol/L increase in L0, with L0 accounting for 12% of the variability in PRISM-III scores between patients. There was no association between L0 and PICU or hospital length of stay.

CONCLUSIONS

Although our single center study did not demonstrate that an elevated early lactate is associated with mortality in pediatric severe sepsis, L0 did correlate strongly with PRISM-III, the most robust measure of mortality risk in pediatrics. Therefore, early lactate measurement may be important as an early biomarker of disease severity. These data should be validated in a larger, multicenter, prospective study.

Persistent Hyperlactatemia as the Predictor of Poor Outcome in Critically Ill Children: A Single-Center, Prospective, Observational Cohort Study

Objective  To study incidence of hyperlactatemia and its correlation with outcome in critically ill children. Design  Single-center, prospective cohort study. Setting  Eight-bedded PICU. Method  Serial serum lactate levels were measured in 140 critically ill children at 0, 12, 24, and 48 hours. Results  A total of 45% children had hyperlactatemia. Lactate levels were significantly ( p  = 0.000) higher in nonsurvivors at all intervals. Lactate levels decreased significantly ( p  = 0.000) in survivors while increased in nonsurvivors. Normalized lactate load was found to be an independent predictor of mortality ( p  = 0.023). Conclusion  Persistent hyperlactatemia serves as a possible predictor of poor outcome in critically ill children.

Derivation and Validation of a Mortality Risk Score for Severe Hand, Foot and Mouth Disease in China

Outbreaks of hand, foot and mouth disease (HFMD) have increased recently, as has the case fatality rate in severe cases. No scoring system currently exists to predict mortality risk for severe HFMD in previous study. We retrospectively collected laboratory parameters for 546 patients with severe HFMD (a derivation and a validation cohort) at Hunan Children’s Hospitals between January 2012 and December 2014. We developed a mortality risk score comprising four laboratory parameters: blood glucose (GLU), white blood cells (WBC), lactate (LAC), and N-terminal-probrain natriuretic peptide (NT-proBNP). Using an “optimal” cutoff score of 4, the sensitivity, specificity, positive predictive value and negative predictive value was 88.00%, 96.14%, 62.86% and 99.08%, respectively, in the derivation cohort. Among severe HFMD patients with low- and high-risk scores in the validation cohort, case fatality rates were 1.49% and 74.07%, respectively. According to the “optimal” cut-off in the derivation cohort, the sensitivity, specificity, positive predictive value, and negative predictive value were 80.95%, 93.83%, 62.96% and 97.44%, respectively, in the derivation cohort. The mortality risk score demonstrated good discrimination (AUC > 0.9) and calibration (P > 0.05) in both cohorts. The mortality risk score, comprising WBC, GLU, LAC and NT-proBNP, has been demonstrated good discrimination and calibration in the both cohorts.

Arterial versus venous lactate: a measure of sepsis in children

This study assessed the agreement between arterial and venous blood lactate and pH levels in children with sepsis. This retrospective, three-year study involved 60 PICU patients, with data collected from electronic or paper patient records. The inclusion criteria comprised of children (≤17 years old) with sepsis and those who had a venous blood gas taken first with an arterial blood gas taken after within one hour. The lactate and pH values measured through each method were analysed. There is close agreement between venous and arterial lactate up to 2 mmol/L. As this value increases, this agreement becomes poor. The limits of agreement (LOA) are too large (±1.90 mmol/L) to allow venous and arterial lactate to be used interchangeably. The mean difference and LOA between both methods would be much smaller if derived using lactate values under 2.0 mmol/L. There is close agreement between arterial and venous pH (MD = -0.056, LOA ± 0.121). However, due to extreme variations in pH readings during sepsis, pH alone is an inadequate marker.

CONCLUSION

A venous lactate ≤2 mmol/L can be used as a surrogate for arterial lactate during early management of sepsis in children. However, if the value exceeds 2 mmol/L, an arterial sample must confirm the venous result. What is known: • In children with septic shock, a blood gas is an important test to show the presence of acidosis and high lactic acid. Hyperlactataemia on admission is an early predictor of outcome and is associated with a greater mortality risk. • An arterial sample is the standard for lactate measurement, however getting a sample may be challenging in the emergency department or a general paediatric ward. Venous samples are quicker and easier to obtain. Adult studies generally advise caution in replacing venous lactate values for the arterial standard, whilst paediatric studies are limited in this area. What is new: • This is the first study assessing the agreement between arterial and peripheral venous lactate in children with sepsis, with a significant sample of patients. • This study shows that a venous sample with a lactate of ≤ 2 mmol/L can be used as a surrogate measurement for arterial lactate during early management of sepsis in children. However, if the venous lactate is above 2 mmol/L, an arterial sample must be taken to confirm the result.

The vulnerable microcirculation in the critically ill pediatric patient

In neonates, cardiovascular system development does not stop after the transition from intra-uterine to extra-uterine life and is not limited to the macrocirculation. The microcirculation (MC), which is essential for oxygen, nutrient, and drug delivery to tissues and cells, also develops. Developmental changes in the microcirculatory structure continue to occur during the initial weeks of life in healthy neonates. The physiologic hallmarks of neonates and developing children make them particularly vulnerable during critical illness; however, the cardiovascular monitoring possibilities are limited compared with critically ill adult patients. Therefore, the development of non-invasive methods for monitoring the MC is necessary in pediatric critical care for early identification of impending deterioration and to enable the initiation and titration of therapy to ensure cell survival. To date, the MC may be non-invasively monitored at the bedside using hand-held videomicroscopy, which provides useful information regarding the microcirculation. There is an increasing number of studies on the MC in neonates and pediatric patients; however, additional steps are necessary to transition MC monitoring from bench to bedside. The recently introduced concept of hemodynamic coherence describes the relationship between changes in the MC and macrocirculation. The loss of hemodynamic coherence may result in a depressed MC despite an improvement in the macrocirculation, which represents a condition associated with adverse outcomes. In the pediatric intensive care unit, the concept of hemodynamic coherence may function as a framework to develop microcirculatory measurements towards implementation in daily clinical practice.

Experts' recommendations for the management of cardiogenic shock in children

Cardiogenic shock which corresponds to an acute state of circulatory failure due to impairment of myocardial contractility is a very rare disease in children, even more than in adults. To date, no international recommendations regarding its management in critically ill children are available. An experts’ recommendations in adult population have recently been made (Levy et al. Ann Intensive Care 5(1):52, 2015; Levy et al. Ann Intensive Care 5(1):26, 2015). We present herein recommendations for the management of cardiogenic shock in children, developed with the grading of recommendations’ assessment, development, and evaluation system by an expert group of the Groupe Francophone de Réanimation et Urgences Pédiatriques (French Group for Pediatric Intensive Care and Emergencies). The recommendations cover four major fields of application such as: recognition of early signs of shock and the patient pathway, management principles and therapeutic goals, monitoring hemodynamic and biological variables, and circulatory support (indications, techniques, organization, and transfer criteria). Major principle care for children with cardiogenic shock is primarily based on clinical and echocardiographic assessment. There are few drugs reported as effective in childhood in the medical literature. The use of circulatory support should be facilitated in terms of organization and reflected in the centers that support these children. Children with cardiogenic shock are vulnerable and should be followed regularly by intensivist cardiologists and pediatricians. The experts emphasize the multidisciplinary nature of management of children with cardiogenic shock and the importance of effective communication between emergency medical assistance teams (SAMU), mobile pediatric emergency units (SMUR), pediatric emergency departments, pediatric cardiology and cardiac surgery departments, and pediatric intensive care units.

Validation of lactate clearance at 6 h for mortality prediction in critically ill children

Background and Aims:

To validate the lactate clearance (LC) at 6 h for mortality prediction in Pediatric Intensive Care Unit (PICU)-admitted patients and its comparison with a pediatric index of mortality 2 (PIM 2) score.

Design:

A prospective, observational study in a tertiary care center.

Materials and Methods:

Children <13 years of age, admitted to PICU were included in the study. Lactate levels were measured at 0 and 6 h of admission for clearance. LC and delayed or nonclearance group compared for in-hospital mortality and compared with PIM 2 score for mortality prediction.

Results:

Of the 140 children (mean age 33.42 months) who were admitted to PICU, 23 (16.42%) patients died. For LC cut-off (16.435%) at 6 h, 92 patients qualified for clearance and 48 for delayed or non-LC group. High mortality was observed (39.6%) in delayed or non-LC group as compared to clearance group (4.3%) (P = 0.000). LC cut-off of 16.435% at 6 h (sensitivity 82.6%, specificity 75.2%, positive predictive value 39.6%, and negative predictive value 95.7%) correlates with mortality. Area under receiver operating characteristic (ROC) for LC at 6 h for mortality prediction was 0.823 (P = 0.000). The area under ROC curve for expected mortality prediction by PIM 2 score at admission was 0.906 and at 12.3% cut-off of PIM 2 Score was related with mortality. The mean PIM 2 score was high in delayed or non-LC group (25.25%) compared to LC group (10.95%) (P = 0.004).

Conclusion:

LC cut-off <16.435% at 6 h was associated with high mortality.

Management Issues in Intensive Care Units for Infants and Children with Heart Disease

Admission of infants and children with cardiac disease to the neonatal (NICU) and pediatric ICU (PICU) is ever increasing in India (30-50 % of all admissions). The commonest indication for admission to the NICU or PICU is acute deterioration of cardiac disease. This includes: acute heart failure, hypercyanotic spells, arrhythmias, pericardial tamponade and sick cardiac neonates who need urgent intervention. Other increasingly frequent indications for ICU admission include heart failure with concomitant chest infection and impending respiratory failure and, severe cyanotic heart disease with various stroke syndromes. It is thus essential that a pediatrician be comfortable with the ICU management of such children and that low cost ICU modalities be utilized in order to reach out to as many children as feasible. It is heartening that there is renewed interest in inexpensive therapies like noninvasive ventilation and therapeutic hypothermia.

Lactate clearance as a marker of mortality in pediatric intensive care unit

OBJECTIVE

To correlate lactate clearance with Pediatric Intensive Care Unit (PICU) mortality.

METHODS

45 (mean age 40.15 mo, 60% males) consecutive admissions in the PICU were enrolled between May 2012 to June 2013. Lactate clearance (Lactate level at admission - level 6 hr later x 100 / lactate level at admission) in first 6 hours of hospitalization was correlated to in-hospital mortality and PRISM score.

RESULTS

Twelve out of 45 patients died. 90% died among those with delayed/poor clearance (clearance <30%) compared to 8.5% in those with good clearance (clearance >30%) (P<0.001). Lactate clearance <30% predicted mortality with sensitivity of 75%, specificity of 97%, positive predictive value of 90%, and negative predictive value of 91.42%. Predictability was comparable to PRISM score >30.

CONCLUSION

Lactate clearance at six hours correlates with mortality in the PICU.

Peripheral venous lactate at admission is associated with in-hospital mortality, a prospective cohort study

BACKGROUND

The prognostic value of blood lactate as a predictor of adverse outcome in the acutely ill patient is unclear. The aim of this study was to investigate if a peripheral venous lactate measurement, taken at admission, is associated with in-hospital mortality in acutely ill patients with all diagnosis. Furthermore, we wanted to investigate if the test improves a triage model in terms of predicting in-hospital mortality.

METHODS

We retrieved a cohort of 2272 adult patients from a prospectively gathered acute admission database. We performed regression analysis to evaluate the association between the relevant covariates and the outcome measure: in-hospital mortality.

RESULTS

Lactate as a continuous variable was a risk for in-hospital mortality with an odds ratio (OR) of 1.40 [95% confidence interval (CI) 1.25-1.57, P<0.0001]. OR for in-hospital mortality increased with increasing lactate levels from 2.97 (95% CI 1.55-5.72, P<0.001) for lactate between 2 mmol/l and 4 mmol/l, to 7.77 (95% CI 3.23-18.66, P<0.0001) for lactate>4 mmol/l. If the condition was non-compensated (i.e. pH<7.35), OR for in-hospital mortality increased to 19.99 (7.26-55.06, P<0.0001). Patient with a blood lactate at 4 mmol/l or more had a risk of in-hospital mortality equivalent to the patients in the most urgent triage category.

CONCLUSION

We found elevated admission peripheral venous lactate to be independently associated with in-hospital mortality in the acutely ill patient admitted to the emergency department. Patients with a lactate>4 mmol/l at hospital admission should be considered triaged to the most urgent triage category.

Early-onset thrombocytopenia in near-term and term infants with perinatal asphyxia

BACKGROUND

Neonates after perinatal asphyxia are at increased risk of thrombocytopenia. The correlation between perinatal asphyxia and the risk and severity of early-onset thrombocytopenia is not well known.

OBJECTIVE

To estimate the incidence, severity and risk factors for early-onset thrombocytopenia in neonates after perinatal asphyxia.

METHODS

We included all newborns (gestational age ≥ 36 weeks) admitted to our neonatal nursery due to perinatal asphyxia in this retrospective study. We collected platelet counts that were obtained within the first 48 h of life to estimate the incidence and severity of early-onset thrombocytopenia.

RESULTS

A total number of 171 neonates with perinatal asphyxia were included in the study. The incidence of early-onset thrombocytopenia (platelet count < 150 × 109/l) was 51% (87/171). Several factors were associated with increased risk of early-onset thrombocytopenia, including prolonged prothrombin time (PT) [odds ratio (OR) 1·18, 95% confidence interval (CI) 1·08–1·30, P < 0·01], prolonged activated partial thromboplastin time (APTT) (OR 1·07, 95% CI 1·03–1·11, P < 0·01), low Apgar score at 10 min (OR 1·25, 95% CI 1·08–1·45, P < 0·01) and high serum lactate (OR 1·12, 95% CI 1·06–1·19, P < 0·01). After multiple logistic regression analysis, we found an independent association between early-onset thrombocytopenia and prolonged PT (OR 1·15, 95% CI 1·00–1·33, P = 0·045) and higher lactate level (OR 1·15, 95% CI 1·03–1·28, P = 0·01).

CONCLUSIONS

Early-onset thrombocytopenia occurs frequently in neonates after perinatal asphyxia and is independently associated with PT and lactate level.

Effectiveness of predicting in-hospital mortality in critically ill children by assessing blood lactate levels at admission

BACKGROUND

Hyperlactatemia upon admission is a documented risk factor for mortality in critically ill adult patients. However, the predictive significance of a single lactate measurement at admission for mortality in the general population of critically ill children remains uncertain. This study evaluated the predictive value of blood lactate levels at admission and determined the cut-off values for predicting in-hospital mortality in the critically ill pediatric population.

METHODS

We enrolled 1109 critically ill children who were admitted to a pediatric intensive care unit between July 2008 and December 2010. Arterial blood samples were collected in the first 2 hours after admission, and the lactate levels were determined. The Pediatric Risk of Mortality III (PRISM III) scores were calculated during the first 24 hours after admission.

RESULTS

Of the 1109 children admitted, 115 (10.4%) died in the hospital. The median (interquartile range) blood lactate level in critically ill children was 3.2 mmol/l (2.2-4.8). Among the children, 859 (77.5%) had a lactate concentration >2.0 mmol/l. The blood lactate level upon admission was significantly associated with mortality (odds ratio [OR] = 1.38; 95% confidence interval [CI], 1.30-1.46; p <0.001), even after adjustment for age, gender, and illness severity assessed by PRISM III (OR = 1.27; p <0.001). Multivariate regression analysis showed that a high blood lactate level (OR = 1.17; 95% CI, 1.07-1.29; p = 0.001), a high PRISM III score (OR = 1.15; 95% CI, 1.11-1.20; p <0.001), and a low serum albumin (OR =0.92; 95% CI, 0.88-0.96; p <0.001) were independent risk factors for mortality in critically ill children. Blood lactate achieved an area under-the-receiver-operating-characteristic curve (AUC) of 0.79 (p <0.001) for predicting mortality that was similar to that of PRISM III (AUC = 0.82; p <0.001). The p-value for a comparison of both AUCs was 0.318. Blood lactate displayed a sensitivity of 61% and a specificity of 86% in predicting mortality at the optimal cut-off value of 5.55 mmol/l, and the positive and negative likelihood ratios were 4.5 and 0.45, respectively.

CONCLUSIONS

A high blood lactate level at admission is independently associated with and predictive of in-hospital mortality in the general population of critically ill children.

Advances in monitoring and management of shock

Early recognition and treatment of pediatric shock, regardless of cause, decreases mortality and improves outcome. In addition to the conventional parameters (eg, heart rate, systolic blood pressure, urine output, and central venous pressure), biomarkers and noninvasive methods of measuring cardiac output are available to monitor and treat shock. This article emphasizes how fluid resuscitation is the cornerstone of shock resuscitation, although the choice and amount of fluid may vary based on the cause of shock. Other emerging treatments for shock (ie, temperature control, extracorporeal membrane oxygenation/ventricular assist devices) are also discussed.

The relationship between blood lactate concentration, the Paediatric Index of Mortality 2 (PIM2) and mortality in paediatric intensive care

INTRODUCTION

Blood lactate concentration predicts mortality in neonates, infants, children and adults, with evidence that it has better predictive power than other markers of acid-base status such as absolute base excess or pH.

OBJECTIVE

To investigate whether blood lactate concentration on admission predicts mortality in paediatric intensive care and if its addition can improve the performance of the Paediatric Index of Mortality 2 (PIM2) mortality prediction score.

DESIGN AND SETTING

Retrospective cohort study in one 20-bed UK paediatric intensive care unit (PICU) using data from the PICU clinical and blood gas analyser databases between 2006 and 2010. Only cases with a blood lactate concentration measured at the same time as the PIM2 variables were included. Logistic regression was used to assess if blood lactate concentration predicted mortality independently of PIM2, adjusting for potential confounders, and if it could replace absolute base excess in the PIM2 model.

RESULTS

There were 155 deaths amongst 2,380 admissions (6.5 %). Admission lactate in non-survivors was higher than in survivors (mean [standard deviation, SD]) 6.6 [5.6] versus 3.0 [2.5] mmol/l, had a positive association with mortality [adjusted odds ratio (OR) for death per unit (mmol/l)] increase 1.11 [95 % confidence interval (CI) 1.06-1.16; p < 0.001] and significantly improved the model fit of PIM2 when it replaced absolute base excess (p < 0.001).

CONCLUSIONS

PICU admission blood lactate concentration predicts mortality independently of PIM2. Given the limitations of this study, a prospective multi-centre evaluation is required to establish whether it should be added to the PIM2 model with or without replacement of base excess.

Blood lactate as a predictor for in-hospital mortality in patients admitted acutely to hospital: a systematic review

BACKGROUND

Using blood lactate monitoring for risk assessment in the critically ill patient remains controversial. Some of the discrepancy is due to uncertainty regarding the appropriate reference interval, and whether to perform a single lactate measurement as a screening method at admission to the hospital, or serial lactate measurements. Furthermore there is no consensus whether the sample should be drawn from arterial, peripheral venous, or capillary blood. The aim of this review was: 1) To examine whether blood lactate levels are predictive for in-hospital mortality in patients in the acute setting, i.e. patients assessed pre-hospitally, in the trauma centre, emergency department, or intensive care unit. 2) To examine the agreement between arterial, peripheral venous, and capillary blood lactate levels in patients in the acute setting.

METHODS

We performed a systematic search using PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and CINAHL up to April 2011. 66 articles were considered potentially relevant and evaluated in full text, of these ultimately 33 articles were selected.

RESULTS AND CONCLUSION

The literature reviewed supported blood lactate monitoring as being useful for risk assessment in patients admitted acutely to hospital, and especially the trend, achieved by serial lactate sampling, is valuable in predicting in-hospital mortality. All patients with a lactate at admission above 2.5 mM should be closely monitored for signs of deterioration, but patients with even lower lactate levels should be considered for serial lactate monitoring. The correlation between lactate levels in arterial and venous blood was found to be acceptable, and venous sampling should therefore be encouraged, as the risk and inconvenience for this procedure is minimal for the patient. The relevance of lactate guided therapy has to be supported by more studies.

Serum lactate levels as the predictor of outcome in pediatric septic shock

Background and Aims:

An association of high lactate levels with mortality has been found in adult patients with septic shock. However, there is controversial literature regarding the same in children. The aim of this study was to find the correlation of serum lactate levels in pediatric septic shock with survival.

Settings and Design:

This was a prospective observational study at PICU of a tertiary care center of North India.

Materials and Methods:

A total of 30 children admitted to PICU with diagnosis of septic shock were included in the study. PRISM III score and demographic characteristics of all children were recorded. Serum lactate levels were measured in arterial blood at 0-3, 12, and 24 h of PICU admission. The outcome (survival or death) was correlated with serum lactate levels.

Results:

Septic shock was the most common (79.3%) type of shock and had 50% mortality. Initial as well as subsequent lactate levels were significantly higher in nonsurvivors. A lactate value of more than 45 mg/dl (5 mmol/l) at 0–3, 12, and 24 h of PICU admission had an odds ratio for death of 6.7, 12.5, and 8.6 (95% CI: 1.044–42.431, 1.850–84.442, 1.241–61.683) with a positive predictive value (PPV) of 38%, 71%, 64% and a negative predictive value (NPV) of 80%, 83%, and 83%, respectively.

Conclusions:

Nonsurvivors had higher blood lactate levels at admission as well as at 12 and 24 h. A lactate value of more than 45 mg/dl (5 mmol/l) was a good predictor of death.

Lactate: biomarker and potential therapeutic target

Lactate levels are frequently elevated in critically ill patients and correlate well with disease severity. Elevated lactate levels are prognostic in prehospital, emergency department, and intensive care unit settings. This review discusses the role of lactate as a biomarker in diagnosing and assessing the severity of systemic hypoperfusion, as well as the role of serum lactate measurements in guiding clinical care and enabling prognosis in critically ill patients.

Lactate and acid base as a hemodynamic monitor and markers of cellular perfusion

BACKGROUND

: The intra- and postoperative monitoring of lactate and acid-base has been advocated in pediatric cardiac critical care as surrogate markers of cardiac output, oxygen delivery, and cellular perfusion. Many clinicians use lactate and base excess routinely as markers of tissue perfusion and to assess the effectiveness of their intervention. This review discusses the strengths and weaknesses of using these measurements in pediatric cardiac critical care.

METHODOLOGY

: A search of MEDLINE, EMBASE, PubMed, and the Cochrane Database was conducted to find controlled trials of lactate and base excess. Adult and pediatric data were considered. Guidelines published by the Society of Critical Care Medicine, the American Heart Association, the American Academy of Pediatrics, and the International Liaison Committee on Resuscitation were reviewed including further review of references cited.

RESULTS AND CONCLUSIONS

: Many factors other than tissue hypoxia may contribute to hyperlactemia in critical illness. Although the presence of hyperlactemia on admission appears to be associated with intensive care unit mortality and morbidity in some retrospective analyses, significant overlap between survivors and nonsurvivors means that nonsurvivors cannot be predicted from admission lactate measurement. Persistently elevated postoperative lactate is associated with increased morbidity and mortality in the pediatric cardiac population. To date there is no randomized control trial of goal-directed therapy in adult or pediatric cardiac care that includes normalization of lactate as a target. Overall equivalent time measurements of base excess, anion gap, and pH have a low predictive value for morbidity and mortality in children after cardiac surgery. Lactate is one of a cluster of markers of cellular perfusion and oxygen delivery. Alone, as a single measurement, it has minimal predictive value and is nondiscriminatory for survival.

Children with single-ventricle physiology do not benefit from higher hemoglobin levels post cavopulmonary connection: results of a prospective, randomized, controlled trial of a restrictive versus liberal red-cell transfusion strategy

OBJECTIVE

To examine the impact of a restrictive vs. liberal transfusion strategy on arterial lactate and oxygen content differences in children with single-ventricle physiology post cavopulmonary connection. Children with single-ventricle physiology are routinely transfused postoperatively to increase systemic oxygen delivery, and transfusion thresholds in this population have not been studied.

DESIGN

Prospective, randomized, controlled, clinical trial.

SETTING

Pediatric cardiac intensive care unit in a teaching hospital.

PATIENTS

Infants and children (n = 60) with variations of single-ventricle physiology presenting for cavopulmonary connection.

INTERVENTIONS

Subjects were randomized to a restrictive (hemoglobin of < 9.0 g/dL), or liberal (hemoglobin of ≥ 13.0 g/dL) transfusion strategy for 48 hrs post operation. Primary outcome measures were mean and peak arterial lactate. Secondary end points were arteriovenous (C(a-v)o2) and arteriocerebral oxygen content (C(a-c)o2) differences and clinical outcomes.

MEASUREMENTS AND MAIN RESULTS

A total of 30 children were in each group. There were no significant preoperative differences. Mean hemoglobin in the restrictive and liberal groups were 11 ± 1.3 g/dL and 13.9 ± 0.5 g/dL, respectively (p < .01). No differences in mean (1.4 ± 0.5 mmol/L [Restrictive] vs. 1.4 ± 0.4 mmol/L [Liberal]) or peak (3.1 ± 1.5 mmol/L [Restrictive] vs. 3.2 ± 1.3 mmol/L [Liberal]) lactate between groups were found. Mean number of red blood cell transfusions were 0.43 ± 0.6 and 2.1 ± 1.2 (p < .01), and donor exposure was 1.2 ± 0.7 and 2.4 ± 1.1 to (p < .01), for each group, respectively. No differences were found in C(a-v)o2, C(a-c)o2, or clinical outcome measures.

CONCLUSION

Children with single-ventricle physiology do not benefit from a liberal transfusion strategy after cavopulmonary connection. A restrictive red blood cell transfusion strategy decreases the number of transfusions, donor exposures, and potential risks in these children. Larger studies with clinical outcome measures are needed to determine the transfusion threshold for children post cardiac repair or palliation for congenital heart disease.

Mild hypothermia therapy reduces blood glucose and lactate and improves neurologic outcomes in patients with severe traumatic brain injury

PURPOSE

The study aimed to investigate the association between blood glucose or lactate and the outcomes of severe traumatic brain injury (TBI), and to evaluate the effect of mild hypothermia therapy on glucose and lactate levels.

METHODS

Eighty-one patients with TBI were randomly divided into normothermia (n = 41) and mild hypothermia (n = 40) group. Body temperature of hypothermia group was maintained at 32.7°C for 72 hours. Arterial blood glucose and lactic acid were determined before and after hypothermia therapy. Glasgow Outcome Scale (GOS) score was assessed 3 months after the treatment.

RESULTS

The mean glucose (7.04 ± 0.51 vs 9.71 ± 1.63 mmol/L, P < .05) in the hypothermia group was lower than in the normothermia group after hypothermia therapy. There were more patients with good neurologic function (GOS 4-5) in the hypothermia group than in the normothermia group (75.0% vs 51.2%, P = .038). Multivariate regression analysis showed that blood glucose greater than 10 mmol/L (adjusted risk ratio, 5.7; 95% confidence interval, 1.4-13.2; P < .05) was an independent predictor for poor neurologic outcomes in these patients, and hypothermia therapy was an independent predictor for favorable outcomes (risk ratio, 4.9; 95% confidence interval, 1.0-15.6; P < .05). No significant association between lactate and GOS scores was identified in the multivariate analysis.

CONCLUSION

Hyperglycemia after TBI was associated with poor clinical outcomes, but the predictive value of blood lactate level requires further investigation. Hypothermia therapy improves neurologic outcomes in patients with severe TBI, and reduction in blood glucose may be partially responsible for the improved outcomes.

Sequential plasma lactate concentrations as prognostic indicators in adult equine emergencies

BACKGROUND

Sequential lactate concentration ([LAC]) measurements have prognostic value in that hospitalized humans and neonatal foals that have a delayed return to normolactatemia have greater morbidity and case fatality rate.

HYPOTHESIS

Prognosis for survival is decreased in horses with a delayed return to normal [LAC].

ANIMALS

Two hundred and fifty adult horses presented for emergency evaluation excepting horses evaluated because of only ophthalmologic conditions, superficial wounds, and septic synovitis without systemic involvement.

METHODS

Prospective observational study. [LAC] was measured at admission and then at 6, 12, 24, 48, and 72 hours after admission. The change in [LAC] over time ([LAC]deltaT) was calculated from changes in [LAC] between sampling points.

RESULTS

Median [LAC] was significantly (P < .001) higher at admission in nonsurvivors (4.10 mmol/L [range, 0.60-18.20 mmol/L]) when compared with survivors (1.30 mmol/L [range, 0.30-13.90 mmol/L]) and this difference remained at all subsequent time points. The odds ratio for nonsurvival increased from 1.29 (95% confidence interval 1.17-1.43) at admission to 49.90 (6.47-384) at 72 hours after admission for every 1 mmol/L increase in [LAC]. [LAC]deltaT was initially positive in all horses but became negative and significantly lower in nonsurvivors for the time periods between 24-72 hours (- 0.47, P = .001) and 48-72 hours (- 0.07, P = .032) when compared with survivors (0.00 at both time periods) consistent with lactate accumulation in nonsurvivors.

CONCLUSIONS AND CLINICAL IMPORTANCE

These results indicate that lactate metabolism is impaired in critically ill horses and [LAC]deltaT can be a useful prognostic indicator in horses.

Blood lactate monitoring in critically ill patients: a systematic health technology assessment

OBJECTIVE

To decide whether the use of blood lactate monitoring in critical care practice is appropriate. We performed a systematic health technology assessment as blood lactate monitoring has been implemented widely but its clinical value in critically ill patients has never been evaluated properly.

DATA SOURCE

PubMed, other databases, and citation review.

STUDY SELECTION

We searched for lactate combined with critically ill patients as the target patient population. Two reviewers independently selected studies based on relevance for the following questions: Does lactate measurement: 1) perform well in a laboratory setting? 2) provide information in a number of clinical situations? 3) relate to metabolic acidosis? 4) increase workers' confidence? 5) alter therapeutic decisions? 6) result in benefit to patients? 7) result in similar benefits in your own setting? 8) result in benefits which are worth the extra costs?

DATA EXTRACTION AND SYNTHESIS

We concluded that blood lactate measurement in critically ill patients: 1) is accurate in terms of measurement technique but adequate understanding of the (an)aerobic etiology is required for its correct interpretation; 2) provides not only diagnostic but also important prognostic information; 3) should be measured directly instead of estimated from other acid-base variables; 4) has an unknown effect on healthcare workers' confidence; 5) can alter therapeutic decisions; 6) could potentially improve patient outcome when combined with a treatment algorithm to optimize oxygen delivery, but this has only been shown indirectly; 7) is likely to have similar benefits in critical care settings worldwide; and 8) has an unknown cost-effectiveness.

CONCLUSIONS

The use of blood lactate monitoring has a place in risk-stratification in critically ill patients, but it is unknown whether the routine use of lactate as a resuscitation end point improves outcome. This warrants randomized controlled studies on the efficacy of lactate-directed therapy.

Serial lactate measurements using microdialysis of interstitial fluid do not correlate with plasma lactate in children after cardiac surgery

OBJECTIVES

Serial postoperative blood lactate (BL) concentrations have been shown to predict outcome of children after congenital heart surgery (CHS), and interventions aimed at lowering lactate can improve the outcome of these children. The cumulative blood loss for diagnostic purposes, such as repetitive arterial blood sampling in the intensive care unit, contributes, especially in small children, to anemia. Techniques to limit blood loss can therefore be of use. Microdialysis is a technique to monitor tissue chemistry in various clinical settings, and we hypothesized that it may be a valuable alternative for frequent blood sampling to monitor lactate in children after CHS.

METHODS

Fifteen children with a mean age of 40 months (range, 4-118 months) were prospectively enrolled after CHS. A CMA double lumen microdialysis catheter was inserted into the subcutaneous adipose tissue of the abdominal wall and infused with an isotone mannitol 5% solution at 1 microL/min via the inlet tubing. Microdialysate fluid was collected every hour for 48 hrs and stored at -80 degrees C for lactate determination (interstitial fluid lactate, IFL). Every hour arterial blood was taken for lactate determination. Individual profiles, correlation coefficient, and Bland-Altman analysis were used to compare BL and IFL results.

RESULTS

There were no complications with the microdialysis technique. All patients were discharged alive from hospital. Six hundred twenty paired samples were analyzed. Mean recovery of microdialysate fluid was 84%. Median (interquartile range) was 0.95 (0.70-1.15) mmol/L for BL and 1.13 (0.86-1.48) mmol/L for IFL (p < 0.0001). Individual profiles showed that IFL follows changes in BL in some, but not all children. With this study, we could not explain this discrepancy. The correlation between BL and IFL was poor (r = .77 (p < 0.0001) r = .59). Bland-Altman analysis confirmed the insufficient performance of the current microdialysis-based procedure compared with BL.

CONCLUSION

Serial lactate measurements in microdialysis fluid of subcutaneous adipose tissue are feasible, but cannot be used as a reliable interchangeable method for plasma lactate analysis in children after CHS at this time. Whether this technique has its own place in the assessment of the overall hemodynamic status and tissue perfusion in children after CHS needs to be addressed in future studies.

Lactic acidosis: from sour milk to septic shock

Lactic acidosis is frequently encountered in the intensive care unit. It occurs when there is an imbalance between production and clearance of lactate. Although lactic acidosis is often associated with a high anion gap and is generally defined as a lactate level >5 mmol/L and a serum pH <7.35, the presence of hypoalbuminemia may mask the anion gap and concomitant alkalosis may raise the pH. The causes of lactic acidosis are traditionally divided into impaired tissue oxygenation (Type A) and disorders in which tissue oxygenation is maintained (Type B). Lactate level is often used as a prognostic indicator and may be predictive of a favorable outcome if it normalizes within 48 hours. The routine measurement of serum lactate, however, should not determine therapeutic interventions. Unfortunately, treatment options remain limited and should be aimed at discontinuation of any offending drugs, treatment of the underlying pathology, and maintenance of organ perfusion. The mainstay of therapy of lactic acidosis remains prevention.

Validation of a method to partition the base deficit in meningococcal sepsis: a retrospective study

Introduction

The base deficit is a useful tool for quantifying total acid–base derangement, but cannot differentiate between various aetiologies. The Stewart–Fencl equations for strong ions and albumin have recently been abbreviated; we hypothesised that the abbreviated equations could be applied to the base deficit, thus partitioning this parameter into three components (the residual being the contribution from unmeasured anions).

Methods

The two abbreviated equations were applied retrospectively to blood gas and chemistry results in 374 samples from a cohort of 60 children with meningococcal septic shock (mean pH 7.31, mean base deficit -7.4 meq/L). Partitioning required the simultaneous measurement of plasma sodium, chloride, albumin and blood gas analysis.

Results

After partitioning for the effect of chloride and albumin, the residual base deficit was closely associated with unmeasured anions derived from the full Stewart–Fencl equations (r² = 0.83, y = 1.99 – 0.87x, standard error of the estimate = 2.29 meq/L). Hypoalbuminaemia was a common finding; partitioning revealed that this produced a relatively consistent alkalinising effect on the base deficit (effect +2.9 ± 2.2 meq/L (mean ± SD)). The chloride effect was variable, producing both acidification and alkalinisation in approximately equal proportions (50% and 43%, respectively); furthermore the magnitude of this effect was substantial in some patients (SD ± 5.0 meq/L).

Conclusion

It is now possible to partition the base deficit at the bedside with enough accuracy to permit clinical use. This provides valuable information on the aetiology of acid–base disturbance when applied to a cohort of children with meningococcal sepsis.