Lactate Monitoring Research Articles

The impact of serial lactate monitoring on emergency department resuscitation interventions and clinical outcomes in severe sepsis and septic shock: an observational cohort study.

Monitoring in the setting of critical illness must be linked to beneficial therapy to affect clinical outcome. Elevated serum lactate is associated with an increase in mortality in emergency department (ED) patients with severe sepsis and septic shock. The reduction of lactate levels toward normal during acute resuscitation is associated with improved clinical outcomes. The majority of data demonstrating the interventions used to achieve a reduction in lactate levels and the associated clinical outcomes have been obtained during protocolized randomized trials. We therefore conducted a retrospective observational cohort study of 243 adult patients with severe sepsis and septic shock to assess the interventions associated with nonprotocolized serial lactate monitoring and to assess clinical outcomes. A multivariable model was used to assess outcome differences between the serial lactate (SL) and no serial lactate (NL) cohorts. The SL group received more crystalloid resuscitation (3.6 L vs. 2.5 L; P < 0.01), central venous oxygen saturation monitoring (30% vs. 12%; P < 0.01), and central venous pressure monitoring (23.5% vs. 11.8%; P = 0.02). By day 28, a total of 31 patients in the SL group (23.5%) and 44 in the NL group (39.6%) had died. Multivariable logistic regression analysis demonstrated that the lack of serial lactate monitoring was independently associated with mortality (adjusted odds ratio, 2.09; 95% confidence interval [CI], 1.12 - 3.89; P = 0.02). The SL group also showed greater improvement in 24-h Sequential Organ Failure Assessment scores (1.16 vs. 0.19; P = 0.03), decreased intensive care unit length of stay in days (4.6 vs. 6.0; P = 0.04), and more ventilator-free (19.9 vs. 16; P = 0.05) and vasopressor-free (21.6 vs. 17.9; P = 0.02) days. In the setting of routine clinical care, serial lactate monitoring is associated with an increase in crystalloid administration, resuscitation interventions, and improved clinical outcomes in ED patients with severe sepsis and septic shock. This suggests that serial lactate monitoring, targeting a reduction in lactate levels to normal, is a generalizable resuscitation target in the ED.

In vivo continuous and simultaneous monitoring of brain energy substrates with a multiplex amperometric enzyme-based biosensor device.

Enzyme-based amperometric biosensors are widely used for monitoring key biomarkers. In experimental neuroscience there is a growing interest in in vivo continuous and simultaneous monitoring of metabolism-related biomarkers, like glucose, lactate and pyruvate. The use of multiplex biosensors will provide better understanding of brain energy metabolism and its role in neuropathologies such as diabetes, ischemia, and epilepsy. We have developed and characterized an implantable multiplex microbiosensor device (MBD) for simultaneous and continuous in vivo monitoring of glucose, lactate, and pyruvate. First, we developed and characterized amperometric microbiosensors for monitoring lactate and pyruvate. In vitro evaluation allowed us to choose the most suitable biosensors for incorporation into the MBD, along with glucose and background biosensors. Fully assembled MBDs were characterized in vitro. The calculated performance parameters (LOD, LR, LRS, IMAX and appKM) showed that the multiplex MBD was highly selective and sensitive (LRS≥100 nA/mM) for each analyte and within an adequate range for in vivo application. Finally, MBDs were implanted in the mPFC of anesthetized adult male Wistar rats for in vivo evaluation. Following an equilibration period, baseline brain levels of glucose (1.3±0.2 mM), lactate (1.5±0.4 mM) and pyruvate (0.3±0.1 mM) were established. Subsequently, the MBDs recorded the responses of the animals when submitted to hyperglycemic (40% glucose i.v.) and hypoglycemic (5 U/kg insulin i.v.) challenges. Afterwards, MBDs were recalibrated to convert electrochemical readings into accurate substrate concentrations and to assess biofouling. The presented MBD can monitor simultaneously multiple biomarkers in vivo.

Propylene glycol toxicity in children.

Propylene glycol (PG) is a commonly used solvent for oral, intravenous, and topical pharmaceutical agents. Although PG is generally considered safe, when used in high doses or for prolonged periods, PG toxicity can occur. Reported adverse effects from PG include central nervous system (CNS) toxicity, hyperosmolarity, hemolysis, cardiac arrhythmia, seizures, agitation, and lactic acidosis. Patients at risk for toxicity include infants, those with renal or hepatic insuficiency, epilepsy, and burn patients receiving extensive dermal applications of PG containing products. Laboratory monitoring of PG levels, osmolarity, lactate, pyruvate, bicarbonate, creatinine, and anion gap can assist practitioners in making the diagnosis of PG toxicity. Numerous studies and case reports have been published on PG toxicity in adults. However, very few have been reported in pediatric patient populations. A review of the literature is presented.

Pre-hospital lactate monitoring for adults with sepsis

Background: Sepsis is a life-threatening condition that claims 37 000 lives in the UK. The sepsis six care bundle was developed by the surviving sepsis campaign in 2002 to address this high mortality rate. Part of this care bundle involves measuring blood lactate which is prognostic of mortality. Lactate can be measured by paramedics in the pre-hospital setting using hand held monitors similar to blood glucose machines, with accuracy that is comparable to laboratory measured lactate. Method: A focused electronic literature search was carried out on a number of different databases as well as a hand search of specific relevant journals. Data was also obtained from reference harvesting, although the limitations of this was appreciated. Experts in the field were also contacted with relevant data obtained. An ongoing pre-hospital trial monitoring lactate was also identified and these researchers were contacted with relevant data obtained. Conclusions: Pre-hospital lactate monitoring would promote better recognition of sepsis in adults and improve the quality of care. It could be used to initiate a specific treatment regime such as intravenous antibiotics. This would reduce the numbers of patients admitted to intensive care, helping to reduce mortality and costs for the NHS.

Long-term microfluidic glucose and lactate monitoring in hepatic cell culture.

Monitoring cellular bioenergetic pathways provides the basis for a detailed understanding of the physiological state of a cell culture. Therefore, it is widely used as a tool amongst others in the field of in vitro toxicology. The resulting metabolic information allows for performing in vitro toxicology assays for assessing drug-induced toxicity. In this study, we demonstrate the value of a microsystem for the fully automated detection of drug-induced changes in cellular viability by continuous monitoring of the metabolic activity over several days. To this end, glucose consumption and lactate secretion of a hepatic tumor cell line were continuously measured using microfluidically addressed electrochemical sensors. Adapting enzyme-based electrochemical flat-plate sensors, originally designed for human whole-blood samples, to their use with cell culture medium supersedes the common manual and laborious colorimetric assays and off-line operated external measurement systems. The cells were exposed to different concentrations of the mitochondrial inhibitor rotenone and the cellular response was analyzed by detecting changes in the rates of the glucose and lactate metabolism. Thus, the system provides real-time information on drug-induced liver injury in vitro.

Continuous and Simultaneous Electrochemical Measurements of Glucose, Lactate, and Ascorbate in Rat Brain Following Brain Ischemia

Developing new tools and technologies to enable recording the dynamic changes of multiple neurochemicals is the essence of better understanding of the molecular basis of brain functions. This study demonstrates a microfluidic chip-based online electrochemical system (OECS) for in vivo continuous and simultaneous monitoring of glucose, lactate, and ascorbate in rat brain. To fabricate the microfluidic chip-based detecting system, a microfluidic chip with patterned channel is developed into an electrochemical flow cell by incorporating the chip with three surface-modified indium-tin oxide (ITO) electrodes as working electrodes, a Ag/AgCl wire as reference electrode, and a stainless steel tube as counter electrode. Selective detection of ascorbate is achieved by the use of single-walled carbon nanotubes (SWNTs) to largely facilitate the electrochemical oxidation of ascorbate, while a dehydrogenase-based biosensing mechanism with methylene green (MG) adsorbed onto SWNTs as an electrocatalyst for the oxidation of dihydronicotiamide adenine dinucleotide (NADH) is employed for biosensing of glucose and lactate. To avoid the crosstalk among three sensors, the sensor alignment is carefully designed with the SWNT-modified electrode in the upstream channel and paralleled glucose and lactate biosensors in the downstream channels. With the microfluidic chip-based electrochemical flow cell as the detector, an OECS is successfully established by directly integrating the microfluidic chip-based electrochemical flow cell with in vivo microdialysis. The OECS exhibits a good linear response toward glucose, lactate, and ascorbate with less crosstalk. This property, along with the high stability and selectivity, enables the OECS for continuously monitoring three species in rat brain following brain ischemia.

Early lactate-guided therapy in cardiac surgery patients: a randomized controlled trial

It is unknown whether lactate monitoring aimed to decrease levels during the first hours in patients undergoing cardiac surgery improves outcome. The aim of this study was to evaluate the effect of lactate monitoring and resuscitation directed at decreasing lactate levels in patients admitted to the ICU in the first 8 hours with lactate level ≥3.0 mEq/l.

Introducing intravascular microdialysis for continuous lactate monitoring in patients undergoing cardiac surgery: a prospective observational study

IntroductionLactate is a marker of hypoperfusion and may be used for risk assessment in critically ill patients. Although evidence suggests that repeated lactate measurements are of clinical interest, how and when lactate should be analyzed is controversial. Intravascular microdialysis provides a novel method for the continuous monitoring of lactate, which may be clinically beneficial in critically ill patients.MethodsCirculating lactate levels were continuously monitored in 80 patients undergoing cardiac surgery using either a separate single-lumen microdialysis catheter or a triple-lumen central venous catheter with an integrated microdialysis function. The catheter was placed with the tip positioned in the superior vena cava. Arterial blood gas samples were taken every hour to obtain reference values, and the lactate levels were analyzed in a blood gas analyzer.ResultsA total of 1,601 paired microdialysis–arterial blood gas lactate samples were obtained. Bland-Altman analysis showed a bias (mean difference) ± limits of agreement (±1.96 SD) of 0.02 ± 0.42 mmol/L. The regression coefficient was 0.98 (P = 0.0001).ConclusionsCentral venous microdialysis is an accurate and reliable method for continuous blood lactate monitoring in patients undergoing cardiac surgery. The system may be useful for early lactate-guided therapy in critically ill patients.

Compliance with severe sepsis bundles and its effect on patient outcomes of severe community-acquired pneumonia in a limited resources country.

IntroductionValidation of compliance with severe sepsis bundles is still needed. The purpose of this study was to determine compliance and its outcomes in severe community-acquired pneumonia (CAP) patients in a limited resources country.Material and methodsA prospective cohort study of 212 severe CAP patients was carried out. The implementation programme was organized into two continuous phases. The primary outcomes were compliance and hospital mortality.ResultsCompliance with administration of antibiotics and vasopressors as well as plateau pressure on average < 30 cm H2O was high in both groups. In the bundles group, patients received more serum lactate monitoring (62.3% vs. 11.3%), more blood cultures (47.1% vs. 24.5%), more fluid resuscitation (63.2% vs. 26.4%) and volumes infused (1319.8 ±1107.4 ml vs. 461.9 ±799.3 ml), more inotropic dobutamine and/or packed red blood cells (21.7% vs. 10.0%), more low-dose steroids (56.5% vs. 15.0%), and more glucose control (51.9% vs. 6.6%) compared with such patients in the control group. The rates of total compliance with 6-hour, 24-hour, and 6/24-hour bundles in the prospective period were 47.1%, 51.9%, and 42.5%, respectively. Hospital mortality was reduced from 44.3% to 29.2% (p = 0.023) in the bundles group, and the compliant subgroup had a more than twofold decrease in mortality (17.8% vs. 37.7%, p = 0.003). Serum lactate measured, blood cultures, and fluid resuscitation showed independent relationships with decreased mortality.ConclusionsTotal compliance was relatively low, but the implementation of severe sepsis bundles could clearly reduce mortality from severe CAP.

Microdialysis Monitoring of Glucose, Lactate, Glycerol, and Pyruvate in Patients with Diabetic Ketoacidosis

The objective was to assess glucose, lactate, glycerol, and pyruvate concentrations in the interstitial fluid of the adipose tissue as well as the glucose relative recovery coefficient in reference to capillary blood (RC) during the first two days of the standard treatment of diabetic ketoacidosis (DKA) in patients with type 1 and type 2 diabetes. The study group consisted of 19 patients (12 with type 1 diabetes and 7 with type 2 diabetes). The metabolic state of the patients was monitored using the microdialysis technique. The analysis of variance was used to investigate whether the type of diabetes and the duration of treatment influenced the assessed parameters. Concentrations of all the monitored components were stable after the initial 12 h of treatment. Glucose concentration was higher and concentrations of all the other components were lower (p<0.0001) in patients with type 1 diabetes than in patients with type 2 diabetes. Significantly higher RC was observed in patients with type 1 diabetes during the initial 12 h. The results suggest that the standard treatment of DKA is effective in stabilizing a concentration of the studied metabolic components in the interstitial fluid in patients with type 1 and type 2 diabetes despite differences in the glucose concentration at the beginning of the treatment.

On-line sequential injection-capillary electrophoresis for near-real-time monitoring of extracellular lactate in cell culture flasks

Cell culture has replaced many in vivo studies because of ethical and regulatory measures as well as the possibility of increased throughput. Analytical assays to determine (bio)chemical changes are often based on end-point measurements rather than on a series of sequential determinations. The purpose of this work is to develop an analytical system for monitoring cell culture based on sequential injection-capillary electrophoresis (SI-CE) with capacitively coupled contactless conductivity detection (C4D). The system was applied for monitoring lactate production, an important metabolic indicator, during mammalian cell culture. Using a background electrolyte consisting of 25mM tris(hydroxymethyl)aminomethane, 35mM cyclohexyl-2-aminoethanesulfonic acid with 0.02% poly(ethyleneimine) (PEI) at pH 8.65 and a multilayer polymer coated capillary, lactate could be resolved from other compounds present in media with relative standard deviations 0.07% for intraday electrophoretic mobility and an analysis time of less than 10min. Using the human embryonic kidney cell line HEK293, lactate concentrations in the cell culture medium were measured every 20min over 3 days, requiring only 8.73μL of sample per run. Combining simplicity, portability, automation, high sample throughput, low limits of detection, low sample consumption and the ability to up- and outscale, this new methodology represents a promising technique for near real-time monitoring of chemical changes in diverse cell culture applications.

Simultaneous Telemetric Monitoring of Brain Glucose and Lactate and Motion in Freely Moving Rats

A new telemetry system for simultaneous detection of extracellular brain glucose and lactate and motion is presented. The device consists of dual-channel, single-supply miniature potentiostat-I/V converter, a microcontroller unit, a signal transmitter, and a miniaturized microvibration sensor. Although based on simple and inexpensive components, the biotelemetry device has been used for accurate transduction of the anodic oxidation currents generated on the surface of implanted glucose and lactate biosensors and animal microvibrations. The device was characterized and validated in vitro before in vivo experiments. The biosensors were implanted in the striatum of freely moving animals and the biotelemetric device was fixed to the animal's head. Physiological and pharmacological stimulations were given in order to induce striatal neural activation and to modify the motor behavior in awake, untethered animals.

Membrane cut‐off does not influence results regarding the measurement of small molecules – a comparative study between 20‐ and 100‐kDa catheters in hepatic microdialysis

Microdialysis is a method used to monitor hepatic tissue metabolism. Membranes with a molecular cut-off of 20 kilodalton (kDa) are currently used to measure the small metabolites glucose, glycerol, lactate and pyruvate. Using membranes with higher cut-off such as 100 kDa allows the possibility of measuring larger molecules but may affect results regarding small molecules. The aim was to compare microdialysis catheters with a cut-off of 20 and 100 kDa in the measurement of small molecules in a pig liver model. Four microdialysis catheters were inserted into the liver of each pig used in the experiment (n = 6). Two catheters with cut-off of 20 kDa were perfused with Ringer acetate, and two catheters with cut-off of 100 kDa: one perfused with Ringer acetate and one with hydroxyethyl starch (Voluven) at a flow rate of 0·3 μl min(-1). Dialysate samples were collected at 40-min intervals and analysed for glucose, glycerol, lactate and pyruvate. Compared to the other catheters, the 100-kDa catheters perfused with Ringer acetate tended to measure higher dialysate concentrations of the small molecules, the difference reaching statistical significance in the case of pyruvate. Concentrations measured by the 100-kDa catheters perfused with Voluven were, however, comparable to the 20-kDa catheters. Microdialysis catheters with membrane cut-off of 20 and 100 kDa can be used equally in hepatic microdialysis for the monitoring of glucose, glycerol, lactate and pyruvate, and lactate/pyruvate ratio if a high osmotic solution (Voluven) is used to perfuse the 100-kDa catheters.

Metabolism, Metabolome, and Metabolomics in Intensive Care: Is It Time to Move beyond Monitoring of Glucose and Lactate?

Metabolism, Metabolome, and Metabolomics in Intensive Care: Is It Time to Move beyond Monitoring of Glucose and Lactate?

Clinical use of lactate monitoring in critically ill patients

Increased blood lactate levels (hyperlactataemia) are common in critically ill patients. Although frequently used to diagnose inadequate tissue oxygenation, other processes not related to tissue oxygenation may increase lactate levels. Especially in critically ill patients, increased glycolysis may be an important cause of hyperlactataemia. Nevertheless, the presence of increased lactate levels has important implications for the morbidity and mortality of the hyperlactataemic patients. Although the term lactic acidosis is frequently used, a significant relationship between lactate and pH only exists at higher lactate levels. The term lactate associated acidosis is therefore more appropriate. Two recent studies have underscored the importance of monitoring lactate levels and adjust treatment to the change in lactate levels in early resuscitation. As lactate levels can be measured rapidly at the bedside from various sources, structured lactate measurements should be incorporated in resuscitation protocols.

Pre‐Calibrated Biosensors for Single‐Use Applications

AbstractBioprocess development and fermentation control would benefit from a timely knowledge of metabolic parameters, e.g., glucose, glutamine, and lactate concentration etc., enabling adequate intervention, maximizing product yield, and providing process analytical tools for reliable and traceable bioprocessing in the context of process analytical technology. A polymer laminate technology based microsytem comprising integrated pre‐calibrated electrochemical biosensors for the simultaneous monitoring of lactate, glucose, glutamine, and glutamate in a 0.15‐μL flow‐through cell for process monitoring and control is presented. Flexible manufacturing technologies used for these devices allow a cost effective customization of them.

Handheld Point-of-Care Cerebrospinal Fluid Lactate Testing Predicts Bacterial Meningitis in Uganda

We validated a handheld point-of-care lactate (POCL) monitor's ability to measure lactate in cerebrospinal fluid (CSF) and diagnose bacterial meningitis in Uganda. There was a strong linear correspondence between POCL and standard laboratory lactate test results (R(2) = 0.86; P < 0.001). For 145 patients with clinical meningitis, the area under the receiver operating characteristic curve for the prediction of bacterial meningitis by CSF POCL was 0.92 (95% confidence interval = 0.85-0.99, P < 0.001). A CSF POCL concentration of 7.7 mmol/L provided 88% sensitivity and 90% specificity for the diagnosis of bacterial meningitis. CSF POCL testing had excellent use in the diagnosis of bacterial meningitis, and it may be useful where CSF analyses are delayed or laboratory infrastructure is limited.

Web-Based Survey of Current Trends in Hemodynamic Monitoring After Congenital Heart Surgery

Strategies for monitoring patients recovering after congenital heart surgery have evolved considerably as technology continues to progress. Monitoring techniques traditionally centered around the comprehensive physical examination have been replaced by a number of revolutionary technologies developed to objectively evaluate various components of the cardiovascular system. Despite scant evidence that these methodologies actually improve outcomes, some have been embraced by clinicians. We developed an Internet survey designed to describe current practices of clinicians who care for patients after congenital heart surgery. There were 162 respondents to our survey with the majority from the United States. The views of cardiologists, intensivists, those dual trained in both cardiology and critical care medicine, and surgeons are all robustly represented in the results. Serial lactate monitoring was the strategy that was utilized most often by respondents (94%), followed by multisite near-infrared spectrometry (NIRS, 67%). There were 78% who utilized the combination of serial lactate and NIRS monitoring. Serial lactate monitoring was the technique that was thought to best represent cardiovascular well-being after heart surgery (40%). The results of this survey suggest that despite the paucity of evidence that clinical outcomes of patients recovering after congenital heart surgery are improved by any of these monitoring techniques, there is almost universal acceptance to monitor patients with serial lactate monitoring, NIRS monitoring, or a combination of these techniques.

Use of serial measurements of peritoneal fluid lactate concentration to identify strangulating intestinal lesions in referred horses with signs of colic

To determine the value of serial measurements of peritoneal fluid lactate concentration (PFL) for detecting strangulating intestinal lesions (SLs) in referred horses with signs of colic. Retrospective cohort study. 94 horses with signs of colic. Medical records of horses evaluated between September 2006 and February 2010 because of signs of colic were reviewed. All included horses had ≥ 2 peritoneal fluid samples collected, including one at admission and another within 1 to 6 hours after admission. Of the 94 horses, 26 were assigned to the SL group on the basis of findings at surgery or necropsy and 68 were assigned to the nonstrangulating intestinal lesion group because their signs of colic resolved with medical management. Peritoneal fluid lactate concentration was measured by use of a handheld lactate monitor. Data were analyzed by use of univariable and multivariable logistic regression analysis. PFL at admission > 4 mmol/L, an increase in PFL over time, and especially an increase in PFL over time in horses with a PFL < 4 mmol/L at admission (OR, 62; sensitivity, 95%; specificity, 77%) were significant predictors of horses with an SL. Serially determined PFL was a strong predictor for differentiating horses with SLs from horses with nonstrangulating intestinal lesions. Given the high OR, sensitivity, and specificity of these tests, serially determined PFL may have potential as a screening test for identifying horses with SLs. Further evaluation of the clinical value of PFL for predicting SLs in a prospective, multicenter study is warranted.

Cross-correlation analysis of blood and microdialysis-assessed tissue lactate monitoring: a study in critically ill septic patients

In the critical care setting, blood lactate (BL) concentration is measured to assess - albeit indirectly - tissue oxygenation. In addition, serial BL measurements are clinically useful since a drop in BL is a good prognostic finding, whereas persistent BL elevation portends poor outcome. Microdialysis (MD) enables direct monitoring of tissue metabolic changes. This study aimed to describe the dynamics of MD-assessed tissue lactate (TL) vis-a-vis BL in septic patients with and without shock.