Rapid reversal of severe lactic acidosis after thiamine administration in critically ill adults: a report of 3 cases

Therapeutic Strategies Targeting Mitochondrial Dysfunction in Sepsis-induced Cardiomyopathy

Sepsis is an increasingly worldwide problem; it is currently regarded as a complex life-threatening dysfunction of one or more organs as a result of dysregulated host immune response to infections. The heart is one of the most affected organs, as roughly 10% to 70% of sepsis cases are estimated to turn into sepsis-induced cardiomyopathy (SIC). SIC can be defined as a reversible myocardial dysfunction characterized by dilated ventricles, impaired contractility, and decreased ejection fraction. Mitochondria play a critical role in the normal functioning of cardiac tissues as the heart is highly dependent on its production of adenosine triphosphate (ATP), its damage during SIC includes morphology impairment, mitophagy, biogenesis disequilibrium, electron transport chain disturbance, molecular damage from the actions of pro-inflammatory cytokines and many other different impairments that are major contributing factors to the severity of SIC. Although mitochondria-targeted therapies usage is still inadequate in clinical settings, the preclinical study outcomes promise that the implementation of these therapies may effectively treat SIC. This review summarizes the different therapeutic strategies targeting mitochondria structure, quality, and quantity abnormalities for the treatment of SIC.

Pyruvate Dehydrogenase Complex in Neonatal Hypoxic-Ischemic Brain Injury

The disruption of cerebral energy metabolism in relation to brain damage has been the subject of extensive research. However, the pyruvate dehydrogenase complex (PDHC), which is primarily characterized by poor cerebral energy metabolism following brain trauma, has received relatively little study in comparison to newborn hypoxic-ischemic brain injury. Mitochondrial PDHC, a multienzyme complex that functions as a crucial hub in energy metabolism and acts as a central metabolic node to mediate pyruvate oxidation after glycolysis and fuel the Krebs cycle to meet energy demands, has been reported to be one cause of energy metabolism dysfunction according to recent studies. Here we assess the potential mechanisms of neonatal hypoxic-ischemic brain injury-related brain dysfunction mediated by PDHC and further discuss the neuroprotective effects of therapeutic medicines that target PDHC activation. We also provide a summary of recent research on medicines that target PDHC in neonates with hypoxic-ischemic brain damage. Through an understanding of the mechanisms by which it is modulated and an investigation of the neuroprotective techniques available to activate brain PDHC and improve neonatal hypoxic-ischemic impairment, our review emphasizes the significance of PDHC impairment in neonatal hypoxic-ischemic brain injury.

Role of Magnesium in the Intensive Care Unit and Immunomodulation: A Literature Review

Both the role and the importance of magnesium in clinical practice have grown considerably in recent years. Emerging evidence suggests an association between loss of magnesium homeostasis and increased mortality in the critical care setting. The underlying mechanism is still unclear, but an increasing number of in vivo and in vitro studies on magnesium's immunomodulating capabilities may shed some light on the matter. This review aims to discuss the evidence behind magnesium homeostasis in critically ill patients, and its link with intensive care unit mortality via a likely magnesium-induced dysregulation of the immune response. The underlying pathogenetic mechanisms, and their implications for clinical outcomes, are discussed. The available evidence strongly supports the crucial role of magnesium in immune system regulation and inflammatory response. The loss of magnesium homeostasis has been associated with an elevated risk of bacterial infections, exacerbated sepsis progression, and detrimental effects on the cardiac, respiratory, neurological, and renal systems, ultimately leading to increased mortality. However, magnesium supplementation has been shown to be beneficial in these conditions, highlighting the importance of maintaining adequate magnesium levels in the intensive care setting.

Evaluation of blood thiamine concentration in hospitalized dogs with and without critical illness

OBJECTIVE

To evaluate blood thiamine concentration in healthy and critically ill hospitalized dogs over 72 hours of hospitalization and to identify any association of thiamine concentration with patient morbidity and mortality.

DESIGN

Prospective, observational, clinical study.

SETTING

University veterinary teaching hospital.

ANIMALS

Thirty-one hospitalized healthy dogs and 37 dogs with critical illness. Dogs with critical illness had nonseptic (n = 24) or septic (n = 13) etiologies.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Whole blood EDTA samples were collected within 24 hours of admission and 72 hours later. Samples were stored at -80°C and batch analyzed. Total thiamine (tB1) and thiamine diphosphate (TDP) concentrations were measured using high-performance liquid chromatography, and free thiamine concentration was determined using liquid chromatography with tandem mass spectrometry. Collected patient data included CBC, biochemistry profile, plasma lactate concentration, shock index, Acute Patient Physiologic and Laboratory Evaluation Score (APPLE_fast ) score, comorbid conditions, and patient outcome. Approximately 92% of tB1 present in whole blood is measured as TDP. TDP concentration was strongly correlated with tB1 (R = 0.97, P < 0.0001). Thiamine concentration, represented by TDP, was not different at admission or at 72 hours in all dogs. TDP concentration was lower in septic dogs requiring surgery at admission (P = 0.044) and 72 hours later (P = 0.008), compared to dogs not requiring surgery. TDP concentration was not different between dogs with and without stable chronic diseases at any time point. Older dogs had lower TDP concentration. Positive correlations were seen between TDP and body weight, APPLE_fast score, and WBC count. Critically ill dogs with lower admission plasma lactate concentration were more likely to have an increase in thiamine over time (P = 0.0142).

CONCLUSIONS

Differences in thiamine concentration were not identified in hospitalized healthy or critically ill dogs. Further investigation into the clinical relevance of thiamine deficiency is indicated in septic dogs undergoing surgery.

The Pyruvate Dehydrogenase Complex Mitigates LPS-Induced Endothelial Barrier Dysfunction by Metabolic Regulation

ABSTRACT

Sepsis is a fatal health issue induced by an aberrant host response to infection, and it correlates with organ damage and a high mortality rate. Endothelial barrier dysfunction and subsequent capillary leakage play major roles in sepsis-induced multiorgan dysfunction. Anaerobic glycolysis is the primary metabolic mode in sepsis and the pyruvate dehydrogenase complex (PDHC) serves as a critical hub in energy regulation. Therefore, it is important to understand the role of PDHC in metabolic regulation during the development of sepsis-induced endothelial barrier dysfunction.In present study, human umbilical vein endothelial cells (HUVECs) and C57 BL/6 mice were treated with lipopolysaccharide (LPS) as models of endotoxemia. LPS increased basal glycolysis, compensatory glycolysis, and lactate secretion, indicating increased glycolysis level in endothelial cells (ECs). Activation of PDHC with dichloroacetate (DCA) reversed LPS-induced glycolysis, allowing PDHC to remain in the active dephosphorylated state, thereby preventing lactic acid production and HUVECs monolayers barrier dysfunction, as assessed by transendothelial electrical resistance and Fluorescein Isothiocyanate-labeled dextran. The in vivo study also showed that the lactate level and vascular permeability were increased in LPS-treated mice, but pretreatment with DCA attenuated these increases. The LPS-treated HUVEC model showed that DCA reversed LPS-induced phosphorylation of pyruvate dehydrogenase E1α Ser293 and Ser300 to restore PDHC activity. Immunoprecipitation results showed that LPS treatment increased the acetylation level of PDH E1α in HUVECs.Our study suggested that activation of PDHC may represent a therapeutic target for treatment of LPS-induced endothelial barrier dysfunction.

The Pyruvate Dehydrogenase Complex in Sepsis: Metabolic Regulation and Targeted Therapy

Anaerobic glycolysis is the process by which glucose is broken down into pyruvate and lactate and is the primary metabolic pathway in sepsis. The pyruvate dehydrogenase complex (PDHC) is a multienzyme complex that serves as a critical hub in energy metabolism. Under aerobic conditions, pyruvate translocates to mitochondria, where it is oxidized into acetyl-CoA through the activation of PDHC, thereby accelerating aerobic oxidation. Both phosphorylation and acetylation affect PDHC activity and, consequently, the regulation of energy metabolism. The mechanisms underlying the protective effects of PDHC in sepsis involve the regulation on the balance of lactate, the release of inflammatory mediators, the remodeling of tricarboxylic acid (TCA) cycle, as well as on the improvement of lipid and energy metabolism. Therapeutic drugs that target PDHC activation for sepsis treatment include dichloroacetate, thiamine, amrinone, TNF-binding protein, and ciprofloxacin. In this review, we summarize the recent findings regarding the metabolic regulation of PDHC in sepsis and the therapies targeting PDHC for the treatment of this condition.

The Effect of a Single Dose of Thiamine on Oxygen Consumption in Patients Requiring Mechanical Ventilation for Acute Illness: A Phase II, Randomized, Double-Blind, Placebo-Controlled Trial

Lower oxygen consumption is associated with worse survival in septic shock and in other forms of critical illness. No treatment that increases oxygen extraction, a key determinant of oxygen consumption, has been found. Thiamine is required for aerobic metabolism, and deficiency is common in the critically ill.

OBJECTIVES

We evaluated the effect of thiamine on oxygen consumption in patients requiring mechanical ventilation for an acute illness.

DESIGN

Phase II, randomized, double-blind, and placebo-controlled trial.

SETTING AND PARTICIPANTS

ICUs in a tertiary care hospital in the United States. Patients admitted to the ICU and requiring mechanical ventilation were screened for enrollment.

INTERVENTIONS

After enrollment, baseline measurement of oxygen consumption and baseline laboratories including lactate, central venous oxygen saturation, and pyruvate dehydrogenase, a single dose of 200 mg IV thiamine or placebo was administered. Oxygen consumption was then monitored for 6 additional hours and repeat laboratories were drawn at the end of the protocol.

MAIN OUTCOMES AND MEASURES

The primary outcome was the change in oxygen consumption. Analysis was done using linear regression with a first-order autoregressive variance-covariance structure to account for repeated measures within subjects. Secondary outcomes included change in lactate, central venous oxygen saturation, and pyruvate dehydrogenase quantity and activity.

RESULTS

Sixty-seven patients were enrolled. After excluding 11 patients due to inadequate quantity or quality of oxygen consumption data, 56 patients were included. There was no difference in change in oxygen consumption in the 6 hours after study drug. Results for secondary outcomes were similarly negative. In the prespecified subgroup of 18 thiamine deficient patients, there was a difference in the two oxygen consumption curves (p = 0.006), although no difference in median oxygen consumption or area under the curve.

CONCLUSIONS AND RELEVANCE

A single dose of IV thiamine did not alter oxygen consumption in patients requiring mechanical ventilation for acute illness.

Pumpkin, Cauliflower and Broccoli as New Carriers of Thiamine Compounds for Food Fortification

The aim of the study is to explore the possibility of vegetables being used as carriers of thiamine. The influence of carrier type (thiamine hydrochloride—TCh and thiamine pyrophosphate—TP) for the thiamine stability were investigated. Two varieties of pumpkin, Muscat and Hokkaido, as well as Cauliflower and Broccoli, were used as a matrix for the thiamine applied. The impregnated and freeze-dried vegetables were stored (230 days) with changing access to light (access to and restriction of light) and temperature (21 °C and 40 °C). The analyzed carriers were also used in the production of gnocchi dumplings. The content of thiamine was analyzed using the thiochromium method. In the study, consumer tests (n = 199) and sensory profiling were used to assess the impact of thiamine carriers on the sensory quality of gnocchi dumplings. It was found that the introduction of dried vegetables at the level of 30% allows for high sensory desirability of analyzed products, as well as suggesting the possibility of their frequent consumption. Such a product could potentially become an alternative to pork meat as a good source of thiamine. However, it should be noted that the thiamine losses may occur during the storage of dried vegetables and their culinary preparation.

ABC's of Vitamin Supplementation in Critical Illness

Critical illness commonly presents as a systemic inflammatory process. Through this inflammation, there is an enhanced production of reactive oxygen and nitrogen species combined with marked reductions in protective plasma antioxidant concentrations. This imbalance is referred to as oxidative stress and is commonly encountered in numerous disease states in the critically ill including sepsis, trauma, acute respiratory distress syndrome, and burns. Oxidative stress can lead to cellular, tissue and organ damage as well as increased morbidity and mortality in critically ill patients. Supplementation with exogenous micronutrients to restore balance and antioxidant concentrations in critically ill patients has been considered for several decades. It is proposed that antioxidant vitamins, such as vitamins A and C, may minimize oxidative stress and improve clinical outcomes. Vitamin B formulations may play a role in curtailing lactic acidosis and are recently being evaluated as an acute phase reactant. However, few large, randomized trials specifically investigating the role of vitamin supplementation in the critically ill patient population are available. This article seeks to review recently published literature surrounding the role of supplementation of vitamins A, B and C in critically ill patients.

Lactic Acidosis Secondary to Thiamin Deficiency Following Autologous Stem Cell Transplantation

A 22-month-old female with high-risk neuroblastoma completed 5 cycles of chemotherapy then underwent high-dose chemotherapy with autologous stem cell rescue (ASCR). Parenteral nutrition was administered from day +2 following ASCR, as she was unable to tolerate nasogastric feeds because of grade IV mucositis and vomiting. On day +12, she developed worsening metabolic acidosis with above reportable levels of lactic acid. Given the patient's well clinical appearance and paucity of evidence of end-organ dysfunction on physical examination and on laboratory studies, there was high suspicion that the patient's lactic acidosis did not result from tissue hypoxia and was, in fact, a type B lactic acidosis. Thiamin was empirically administered, with rapid improvement in lactic acidosis. Thiamin deficiency was later confirmed by laboratory studies drawn prior to thiamin administration.

Severe Lactic Acidosis in a Critically Ill Child: Think About Thiamine! A Case Report

In this article, we presented a teenager, in maintenance chemotherapy for leukemia, who was admitted for digestive symptoms related to a parasitic infection and required nutritional support with parenteral nutrition. After 6 weeks, his condition worsened with refractory shock of presumed septic origin, necessitating extracorporeal membrane oxygenation. Despite hemodynamic stabilization, his lactic acidosis worsened until thiamine supplementation was started. Lactate normalized within 12 hours. Thiamine is an essential coenzyme in aerobic glycolysis, and deficiency leads to lactate accumulation through anaerobic glycolysis. Thiamine deficiency is uncommon in the pediatric population. However, it should be considered in patients at risk of nutritional deficiencies with lactic acidosis of unknown origin.

Thiamine pyrophosphate diminishes nitric oxide synthesis in endothelial cells

Although thiamine pyrophosphate (TPP) is considered a protective agent for endothelial cells, it is still unknown if this is associated with nitric oxide (NO) synthesis. Our aim was to evaluate the synthesis of NO in endothelial cells incubated with TPP and high glucose concentrations. Endothelial cells from the umbilical cord vein from newborns (n = 20), were incubated with 5, 15 or 30 mmol/L glucose, in absence or presence of 0.625 mg/ml of TPP. Our results showed a significant increase in cell proliferation (> 40%; P < 0.05), and cell viability (> 90%; P < 0.001) after 48 h in endothelial cells cultured with glucose plus TPP. Likewise, in the presence of glucose and TPP an important rise in the consumption of glucose by the endothelial cells was observed after 24 h (> 7%; P < 0.001) and 48 h (> 10%; P < 0.05). Additionally, the levels of lactate after incubation with glucose and TPP showed only slight variations after 48 h (P < 0.05). However, these changes were clearly different from those observed in the absence of TPP. Interestingly, we found that the changes mentioned were linked with reduced levels of nitrites both at 24 h (< 171 pmol/μg protein; P < 0.001), and 48 h (< 250 pmol/μg protein; P < 0.05), which was associated with a reduced expression of mRNA of eNOS in endothelial cells incubated with TPP and high glucose. In conclusion, the presence of TPP regulates the consumption of glucose and the synthesis of NO, which would explain its protective effect in the endothelium of diabetic patients.

Stability of high-dose thiamine in parenteral nutrition for treatment of patients with Wernicke's encephalopathy

BACKGROUND & AIMS

Wernicke's encephalopathy is associated mainly with malnourishment in alcohol-dependent patients but can be caused also by cancer, Crohn's disease, gastrointestinal surgery or prolonged parenteral nutrition (PN) without adequate supplementation of vitamins. The disorder, with a significant mortality rate of up to 20%, is often associated with the underlying disease and intensifies after administration of non-supplemented PN. Thus, it seems justified to add thiamine to PN admixtures prepared for parenterally fed patients. Due to the lack of data on the stability of thiamine in PN admixtures at concentrations exceeding 60 mg/L, we decided to determine the possibility of adding a high dose of thiamine (800 mg per bag, 320 mg/L) to PN admixtures in order to treat Wernicke's encephalopathy in malnourished patients.

METHODS

The study aimed to assess the stability of the physical properties of PN admixtures (pH, zeta potential, particle size) and to determine thiamine content using an HPLC method.

RESULTS

Thiamine was found to degrade regardless of the PN admixture composition and storage conditions. The highest decrease in thiamine content was observed at room temperature without light protection whereas the lowest at a temperature of 4 ± 1 °C with light protection.

CONCLUSIONS

The treatment of Wernicke's encephalopathy in parenterally fed patients is possible with the use of high thiamine doses (800 mg) added to PN admixtures without a decrease in the drug content above 10% within the first 24 h. It should be emphasized that thiamine as a photosensitive drug must be stored and administered under conditions ensuring light protection.

Effect of magnesium supplementation on lactate clearance in critically ill patients with severe sepsis: a randomized clinical trial

OBJECTIVES

In this study, changes in lactate clearance following magnesium supplementation were evaluated in critically ill patients with severe sepsis.

METHODS

Fifty-eight patients with severe sepsis were randomly assigned to receive either magnesium (n = 30) or placebo (n = 28). Patients in the magnesium group received intravenous magnesium sulfate to maintain serum magnesium level around 3 mg/dL for 3 days. The placebo group received the same volume of normal saline. Change in lactate clearance was considered primary outcome of the study.

RESULTS

Mean increase in the lactate clearance in the magnesium group was significantly higher than the placebo group on day 2 (27.53% vs. 23.79% respectively, p < 0.001) and day 3 (49.83% vs. 37.02% respectively, p < 0.001). Time to lactate clearance was also significantly shorter in the magnesium group than the placebo group (47.28 ± 20.59 vs. 61.20 ± 24.31 h respectively, p = 0.03). Sepsis-related mortality was not significantly different but median length of ICU stay was significantly shorter in the magnesium group than the placebo group (8 vs. 15 days respectively, p < 0.01).

CONCLUSIONS

Magnesium supplementation increased lactate clearance in critically ill patients with severe sepsis. Optimizing serum magnesium level near the upper limit of the normal range may improve severe sepsis outcomes.

Development and validation of a dried blood spot test for thiamine deficiency among infants by HPLC-fluorimetry

Thiamine deficiency, if detected early in infancy, can be treated with thiamine supplementation and can prevent seizures, other disabilities and death. The dried blood spot (DBS) sampling technique is an attractive sample collection technique for infants. The present study reports the development and validation of a highly sensitive and precise method for quantification of thiamine diphosphate from DBS. The method utilizes full-spot analysis of a volumetrically deposited 40 μl DBS. The analyte was extracted from the DBS using 50% methanol and then derivatized using potassium ferricyanide to thiochrome. Separation was achieved with the help of an Inertsil ODS C₁₈ column (5.0 μm, 250 × 4.6 mm) using 150 mm phosphate buffer pH 7-acetonitrile (90:10, % v/v) as the mobile phase. The use of a fluorimetric detector gave a good response to the thiochrome derivative offering good sensitivity for the method. The excitation and emission wavelengths were 367 and 435 nm, respectively. The limit of detection and lower limit of quantification were 5 and 10 ng/ml, respectively. Linearity was demonstrated from 10 to 1000 ng/ml, and precision (CV) was <12.08%, at all tested quality control levels. The method accuracy was 89.34-118.89% with recoveries >80%. Bland-Altman analysis of DBS sampling vs. whole blood demonstrated a mean bias of only 1.16 ng/ml, with a majority of the 60 investigated patient samples lying within 7.2% of the corresponding concentration measured in blood, thereby meeting the clinical desirable biological specification criterion and showing that the two methods are comparable.

Thiamine deficiency affects glucose transport and β-oxidation in rats

Thiamine is recognized as a cofactor for many enzymes involved in intermediary metabolism responsible for energy production. Animal model of thiamine deficiency (TD) included direct evaluation of glucose uptake by estimation of ³H‐deoxyglucose transport across red blood cells membranes and β‐oxidation of fatty acids in isolated leucocytes. Feeding of animals with the thiamine‐deficient diet (0.018 mg/kg diet) for 30 days resulted in disturbances in energy production. The thiamine intake was limited not only by vitamin B₁ deficiency in the diet, but also by time‐dependent drop of feed consumption by rats fed this diet. At the end of experiment, diet consumption in this group of rats was 52% lower than in the control group. This was accompanied by low glucose uptake by erythrocytes of rats suffering vitamin B₁ deficiency for longer time. At the end of experimental period, glucose uptake was over 2 times lower in TD erythrocytes than in control RBC. Such drop of energy production was not compensated by delivery of energy from fatty acid degradation. In leucocytes from TD rats, the β‐oxidation was also suppressed. Observed significant decrease of serum insulin from 2.25 ± 0.25 ng/ml (day 0) to 1.94 ± 0.17 ng/ml (day 30) might have significant impact on observed energy production disorders. The results from this study indicate that the thiamine deficiency significantly reduces feed intake and causes modest abnormalities in glucose and fatty acid utilization.

Vitamin and trace element deficiencies in the pediatric dialysis patient

Pediatric dialysis patients are at risk of nutritional illness secondary to deficiencies in water-soluble vitamins and trace elements. Unlike 25-OH vitamin D, most other vitamins and trace elements are not routinely monitored in the blood and, consequently, the detection of any deficiency may not occur until significant complications develop. Causes of vitamin and trace element deficiency in patients on maintenance dialysis patient are multifactorial, ranging from diminished nutritional intake to altered metabolism as well as dialysate-driven losses of water-soluble vitamins and select trace elements. In this review we summarize the nutritional sources of key water-soluble vitamins and trace elements with a focus on the biological roles and clinical manifestations of their respective deficiency to augment awareness of potential nutritional illness in pediatric patients receiving maintenance dialysis. The limited pediatric data on the topic of clearance of water-soluble vitamins and trace elements by individual dialysis modality are reviewed, including a brief discussion on clearance of water-soluble vitamins and trace elements with continuous renal replacement therapy.

Thiamine Deficiency: An Important Consideration in Critically Ill Patients

Thiamine is an essential cofactor for 4 enzymes involved in the production of energy (ATP) and the synthesis of essential cellular molecules. The total body stores of thiamine are relatively small, and thiamine deficiency can develop in patients secondary to inadequate nutrition, alcohol use disorders, increased urinary excretion and acute metabolic stress. Patients with sepsis are frequently thiamine deficient, and patients undergoing surgical procedures can develop thiamine deficiency. This deficiency can cause congestive heart failure, peripheral neuropathy, Wernicke's encephalopathy, Korsakoff's syndrome and gastrointestinal beriberi. In addition, thiamine deficiency can contribute to the development of intensive care unit complications, such as heart failure, delirium, critical care neuropathy, gastrointestinal dysfunction and unexplained lactic acidosis. Consequently, clinicians need to consider thiamine deficiency in patients admitted to intensive care units and the development of thiamine deficiency during the management of critically ill patients. Intravenous thiamine can correct lactic acidosis, improve cardiac function and treat delirium.

Is refeeding syndrome relevant for critically ill patients?

PURPOSE OF REVIEW

To summarize recent relevant studies regarding refeeding syndrome (RFS) in critically ill patients and provide recommendations for clinical practice.

RECENT FINDINGS

Recent knowledge regarding epidemiology of refeeding syndrome among critically ill patients, how to identify ICU patients at risk, and strategies to reduce the potential negative impact on outcome are discussed.

SUMMARY

RFS is a potentially fatal acute metabolic derangement that ultimately can result in marked morbidity and even mortality. These metabolic derangements in ICU patients differ from otherwise healthy patients with RFS, as there is lack of anabolism. This is because of external stressors inducing a hypercatabolic response among other reasons also reflected by persistent high glucagon despite initiation of feeding. Lack of a proper uniform definition complicates diagnosis and research of RFS. However, refeeding hypophosphatemia is commonly encountered during critical illness. The correlations between risk factors proposed by international guidelines and the occurrence of RFS in ICU patients remains unclear. Therefore, regular phosphate monitoring is recommended. Based on recent trials among critically ill patients, only treatment with supplementation of electrolytes and vitamins seems not sufficient. In addition, caloric restriction for several days and gradual increase of caloric intake over days is recommendable.

Thiamine in septic shock patients with alcohol use disorders: An observational pilot study

PURPOSE

Alcohol-use disorders (AUDs) have been associated with increased sepsis-related mortality. As patients with AUDs are often thiamine deficient, we investigated practice patterns relating to thiamine administration in patients with AUDs presenting with septic shock and explored the association between receipt of thiamine and mortality.

MATERIALS

We performed a retrospective cohort study of patients presenting with septic shock between 2008 and 2014 at a single tertiary care center. We identified patients with an AUD diagnosis, orders for microbial cultures and use of antibiotics, vasopressor dependency, and lactate levels≥4mmol/L. We excluded those who received thiamine later than 48h of sepsis onset.

RESULTS

We included 53 patients. Thirty-four (64%) patients received thiamine. Five patients (15%) received their first thiamine dose in the emergency department. The median time to thiamine administration was 9 (quartiles: 4, 18) hours. The first thiamine dose was most often given parenterally (68%) and for 100mg (88%). In those receiving thiamine, 15/34 (44%) died, compared to 15/19 (79%) of those not receiving thiamine, p=0.02.

CONCLUSIONS

A considerable proportion of patients with AUDs admitted for septic shock do not receive thiamine. Thiamine administration in this patient population was associated with decreased mortality.

Pyruvate Dehydrogenase Activity Is Decreased in the Peripheral Blood Mononuclear Cells of Patients with Sepsis. A Prospective Observational Trial

RATIONALE

Rodent studies have shown that pyruvate dehydrogenase (PDH) levels are low in sepsis. This may cause cells to shift to anaerobic metabolism, resulting in increased lactate production. Alterations in PDH during sepsis have never been studied in humans.

OBJECTIVES

The objective of this pilot study was to measure PDH activity and quantity in patients with severe sepsis.

METHODS

We conducted a pilot case-control study at a single urban tertiary care center. We compared PDH activity and quantity between patients with severe sepsis admitted to the intensive care unit and healthy control subjects. PDH activity and quantity were measured in isolated peripheral blood mononuclear cells. We measured PDH activity and quantity in control subjects at baseline and in patients with sepsis at 0 (baseline), 24, 48, and 72 hours.

MEASUREMENTS AND MAIN RESULTS

We enrolled 56 patients with sepsis and 20 control subjects with at least one blood sample being drawn from each patient. PDH activity and quantity in the sepsis group were significantly lower than the control group (P < 0.001). In multivariable linear regression adjusting for age, race, sex, and assay plate, the difference remained significant. Patients with sepsis who died had significantly lower PDH activity compared with those who survived (P = 0.03).

CONCLUSIONS

PDH activity and quantity is decreased in peripheral blood mononuclear cells of humans with severe sepsis when compared with healthy control subjects, and may be associated with mortality. Whether decreased PDH activity plays a role in lactate metabolism or whether pharmacologic modification of PDH activity may improve outcomes remains unknown.

Thiamine Levels During Intensive Insulin Therapy in Critically Ill Patients

Introduction:

Thiamine is an essential cofactor in carbohydrate metabolism, and deficiency can therefore cause various organ dysfunctions. Little is known about the prevalence and possible worsening of thiamine deficiency in critically ill patients. In this study, we investigated the prevalence of thiamine deficiency at admission to the intensive care unit (ICU) and hypothesized that intensive insulin therapy, aimed at regulating glucose levels, increases thiamine utilization and therefore might cause or worsen deficiency in patients with limited thiamine stores.

Materials and Methods:

An observational prospective cohort study was carried out in a medical–surgical ICU in a general teaching hospital in Apeldoorn, the Netherlands. All adults who were treated during that time with intensive insulin therapy were included. Deficiency was defined as a thiamine level <100 nmol/L. No thiamine supplementation was administered except for normal amounts present in standard enteral feeding.

Results:

A total of 58 patients were available for analysis. Median thiamine level at admission was 111 nmol/L. Deficiency was present in 39.7% of patients and was significantly associated with the presence of gastrointestinal pathology and with recent surgery. Thiamine levels increased a median of 14 nmol/L in 48 hours. Only 3.4% of patients showed a predefined relevant decline in thiamine levels.

Conclusion:

Intensive insulin therapy does not appear to cause or worsen thiamine deficiency. However, based on the high prevalence of deficiency at admission, it might be warranted to supplement thiamine in all patients admitted to the ICU, especially when there is an underlying gastrointestinal disease or recent surgery.

Thiamine Deficiency in Tropical Pediatrics: New Insights into a Neglected but Vital Metabolic Challenge

In humans, thiamine is a micronutrient prone to depletion that may result in severe clinical abnormalities. This narrative review summarizes current knowledge on thiamine deficiency (TD) and bridges the gap between pathophysiology and clinical presentation by integrating thiamine metabolism at subcellular level with its function to vital organs. The broad clinical spectrum of TD is outlined, with emphasis on conditions encountered in tropical pediatric practice. In particular, TD is associated with type B lactic acidosis and classic forms of beriberi in children, but it is often unrecognized. Other severe acute conditions are associated with hypermetabolism, inducing a functional TD. The crucial role of thiamine in infant cognitive development is also highlighted in this review, along with analysis of the potential impact of TD in refeeding syndrome during severe acute malnutrition (SAM). This review aims to increase clinical awareness of TD in tropical settings where access to diagnostic tests is poor, and advocates for an early therapeutic thiamine challenge in resource-limited settings. Moreover, it provides evidence for thiamine as treatment in critical conditions requiring metabolic resuscitation, and gives rationale to the consideration of increased thiamine supplementation in therapeutic foods for malnourished children.

Randomized, Double-Blind, Placebo-Controlled Trial of Thiamine as a Metabolic Resuscitator in Septic Shock: A Pilot Study

OBJECTIVE

To determine if intravenous thiamine would reduce lactate in patients with septic shock.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Two US hospitals.

PATIENTS

Adult patients with septic shock and elevated (> 3 mmol/L) lactate between 2010 and 2014.

INTERVENTIONS

Thiamine 200 mg or matching placebo twice daily for 7 days or until hospital discharge.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was lactate levels 24 hours after the first study dose. Of 715 patients meeting the inclusion criteria, 88 patients were enrolled and received study drug. There was no difference in the primary outcome of lactate levels at 24 hours after study start between the thiamine and placebo groups (median: 2.5 mmol/L [1.5, 3.4] vs. 2.6 mmol/L [1.6, 5.1], p = 0.40). There was no difference in secondary outcomes including time to shock reversal, severity of illness and mortality. 35% of the patients were thiamine deficient at baseline. In this predefined subgroup, those in the thiamine treatment group had statistically significantly lower lactate levels at 24 hours (median 2.1 mmol/L [1.4, 2.5] vs. 3.1 [1.9, 8.3], p = 0.03). There was a statistically significant decrease in mortality over time in those receiving thiamine in this subgroup (p = 0.047).

CONCLUSION

Administration of thiamine did not improve lactate levels or other outcomes in the overall group of patients with septic shock and elevated lactate. In those with baseline thiamine deficiency, patients in the thiamine group had significantly lower lactate levels at 24 hours and a possible decrease in mortality over time.