Dysoxia and lactate

Thresholds for Red Blood Cell Transfusion in Preterm Infants: Evidence to Practice

Rapid blood loss with circulatory shock is dangerous for the preterm infant as cardiac output and oxygen-carrying capacity are simultaneously imperilled. This requires prompt restoration of circulating blood volume with emergency transfusion. It is recommended that clinicians use both clinical and laboratory responses to guide transfusion requirements in this situation. For preterm infants with anemia of prematurity, it is recommended that clinicians use a restrictive algorithm from one of two recently published clinical trials. Transfusion outside these algorithms in very preterm infants is not evidence-based and is actively discouraged.

Analysis of Intraoperative Variables Responsible for the Increase in Lactic Acid in Patients Undergoing Debulking Surgery

Background: Cytoreductive surgery (CRS) is a complex procedure with a high incidence of perioperative complications. Elevated lactacidaemia levels have been associated with complications and perioperative morbidity and mortality. This study aims to analyse the intraoperative variables of patients undergoing CRS and their relationship with lactacidaemia levels. Methods: This retrospective, observational study included 51 patients with peritoneal carcinomatosis who underwent CRS between 2014 and 2016 at the Abdomino-Pelvic Oncological Surgery Reference Unit (URCOAP) of the General University Hospital of Castellón (HGUCS). The main variable of interest was the level of lactic acid at the end of surgery. Intraoperative variables, including preoperative haemoglobin, duration of surgery, intraoperative bleeding, fluid therapy administered, administration of blood products, and intraoperative peritoneal cancer index (PCI), were analysed. Results: Positive correlations were found between lactic acid levels and PCI, duration of intervention, fluid therapy, intraoperative bleeding, and transfusion of blood products. Additionally, a negative correlation was observed between haemoglobin levels and lactic acid levels. Notably, the strongest correlations were found with operative PCI (ρ = 0.532; p-value < 0.001) and duration of surgery (ρ = 0.518; p-value < 0.001). Conclusions: PCI and duration of surgery are decisive variables in determining the prognosis of patients undergoing debulking surgery. This study suggests that, for each minute of surgery, lactic acid levels increase by 0.005 mmol/L, and for each unit increase in PCI, lactic acid levels increase by 0.060 mmol/L.

Telfairia occidentalis stimulates hepatic glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms

Background

Telfairia occidentalis (TO), a plant consumed for its nutritional and medicinal values, exhibits hypoglycaemic effect. However, the metabolic fate of the glucose following TO-induced insulin secretion and consequent hypoglycaemia is not clear.

Objective

This study determined the effect of ethyl acetate and n-hexane fractions of TO leaf extracts on some biochemical parameters in the glucose metabolic pathway to explain the possible fate of blood glucose following TO-induced hypoglycaemia.

Methods

Eighteen male Wistar rats (180-200 g) divided into control, n-hexane TO fraction- and ethyl acetate TO fraction-treated groups (n = 6/group) were used. The control animals received normal saline while the treated groups received TO at 100 mg/kg for seven days. After 24 h following the last dose, the animals were anaesthetised using ketamine; blood samples were collected and livers harvested to determine some biochemical parameters.

Results

Ethyl acetate TO fraction significantly increased plasma insulin, liver glucokinase activity and plasma pyruvate concentration, but significantly decreased plasma glucose and liver glycogen, without significant changes in plasma lactate, glucose-6-phosphate, liver glucose-6-phosphatase and lactate dehydrogenase activities when compared with control. N-hexane TO fraction significantly reduced liver glucose-6-phosphatase activity and glycogen but significantly increased plasma pyruvate, without significant changes in plasma glucose, insulin, glucose-6-phosphate and lactate concentrations; and liver glucokinase and lactate dehydrogenase activities.

Conclusion

The present study showed that insulin-mediated TO-induced hypoglycaemia resulted in the stimulation of glycolysis and pyruvate production via insulin-dependent and insulin-independent mechanisms.

The effect of oral triiodothyronine supplementation on lactate and pyruvate after paediatric cardiac surgery

OBJECTIVE

To determine if triiodothyronine alters lactate, glucose, and pyruvate metabolism, and if serum pyruvate concentration could serve as a predictor of low cardiac output syndrome in children after cardiopulmonary bypass procedures.

METHODS

This study was ancillary to the Oral Triiodothyronine for Infants and Children undergoing Cardiopulmonary bypass (OTICC) trial. Serum pyruvate was measured in the first 48 patients and lactate and glucose were measured in all 208 patients enrolled in the OTICC study on the induction of anaesthesia, 1 and 24 hours post-aortic cross-clamp removal. Patients were also defined as having low cardiac output syndrome according to the OTICC trial protocol.

RESULT

Amongst the designated patient population for pyruvate analysis, 22 received placebo, and 26 received triiodothyronine (T3). Lactate concentrations were nearly 20 times greater than pyruvate. Lactate and pyruvate levels were not significantly different between T3 and placebo group. Glucose levels were significantly higher in the placebo group mainly at 24-hour post-cross-clamp removal. Additionally, lactate and glucose levels peaked at 1-hour post-cross-clamp removal in low cardiac output syndrome and non-low cardiac output syndrome patients, but subsequently decreased at a slower rate in low cardiac output syndrome. Lactate and pyruvate concentrations correlated with glucose only prior to surgery.

CONCLUSION

Thyroid supplementation does not alter systemic lactate/pyruvate metabolism after cardiopulmonary bypass and reperfusion. Pyruvate levels are not useful for predicting low cardiac output syndrome. Increased blood glucose may be regarded as a response to hypermetabolic stress, seen mostly in patients with low cardiac output syndrome.

Polymeric Tissue Adhesives

Polymeric tissue adhesives provide versatile materials for wound management and are widely used in a variety of medical settings ranging from minor to life-threatening tissue injuries. Compared to the traditional methods of wound closure (i.e., suturing and stapling), they are relatively easy to use, enable rapid application, and introduce minimal tissue damage. Furthermore, they can act as hemostats to control bleeding and provide a tissue-healing environment at the wound site. Despite their numerous current applications, tissue adhesives still face several limitations and unresolved challenges (e.g., weak adhesion strength and poor mechanical properties) that limit their use, leaving ample room for future improvements. Successful development of next-generation adhesives will likely require a holistic understanding of the chemical and physical properties of the tissue-adhesive interface, fundamental mechanisms of tissue adhesion, and requirements for specific clinical applications. In this review, we discuss a set of rational guidelines for design of adhesives, recent progress in the field along with examples of commercially available adhesives and those under development, tissue-specific considerations, and finally potential functions for future adhesives. Advances in tissue adhesives will open new avenues for wound care and potentially provide potent therapeutics for various medical applications.

Evaluation of the relationship between lactacidemia and postoperative complications after surgery for peritoneal carcinomatosis

Background

Cytoreductive surgery was developed as a treatment for peritoneal carcinomatosis. However, this surgery is associated with important complications. The present study aimed to assess the relationship between lactacidemia and the rate of associated complications during the immediate postoperative period in the intensive care unit (ICU) in patients undergoing cytoreductive surgery.

Methods

This was a retrospective observational study. A total of 57 patients underwent cytoreductive surgery. All patients were admitted to the ICU immediately after the surgery. Data on lactic acid levels at the time of admission and discharge from the ICU were collected. Postsurgical complications that occurred during the ICU stay were recorded according to failure-to-rescue analysis and their severity stratified according to the Clavien-Dindo classification.

Results

The lactic acid levels at admission to the ICU were significantly higher in patients who developed complications, with an almost tripled unadjusted relative risk (2.9, 95% CI: 1.6, 5.3), than in those who did not develop complications for the lactacidemia threshold established in the cumulative sum curve graphs. After adjustment for confounding effects, the relative risk became even higher (3.1, 95% CI: 1.8, 3.6). Lactic acid levels were still significantly higher in this group at the time of discharge from the ICU.

Conclusions

Serum lactate level is a risk factor for postoperative complications in patients undergoing cytoreductive surgery for peritoneal carcinomatosis. This study suggests that the risk of developing severe complications almost triples with a lactic acid level of 2.5 mmol/L or higher at the time of admission in the ICU.

Lower limit of adequate oxygen delivery for the maintenance of aerobic metabolism during cardiopulmonary bypass in neonates

BACKGROUND

The objective of cardiopulmonary bypass (CPB) is to maintain an adequate balance between oxygen delivery (Ḋo2) and consumption. The critical Ḋo2 is that at which consumption becomes supply dependent. This study aimed to identify the critical Ḋo2 in neonates, who have higher metabolic rates than adults.

METHODS

In a retrospective cohort of neonates, Ḋo2 was calculated from CPB parameters recorded during aortic cross-clamping. High lactate concentration measured after aortic unclamping (lactOFF) was used to identify anaerobic metabolism. Data were analysed using mixed linear and proportional odds regression models. The relationship between Ḋo2 and temperature was analysed in a subgroup of patients with lactOFF <2.5 mM, thought to have had balanced oxygen delivery and consumption. The estimated regression coefficient was further used to adjust hypothetical Ḋo2 thresholds, and Ḋo2 excursions below the threshold were quantified as magnitude-durations. The lowest threshold that provided magnitude-durations and linked with an increase in lactOFF was used as the lowest suitable (critical) Ḋo2 at 37°C.

RESULTS

Overall, 22 896 time points were analysed in 180 neonates. In 40 patients with lactOFF <2.5 mM, Ḋo2 varied by 22.87 (0.70) ml min-1 m-2 °C-1. When varying the Ḋo2 threshold between 340 and 380 ml min-1 m-2, excursions below the threshold were linked with incremental lactOFF. A 100 ml m-2 excursion below the 340 ml min-1 m-2Ḋo2 threshold increased the risk of a 1 mM increment in lactOFF by 22% (odds ratio: 1.22; 95% confidence interval: 1.02-1.45).

CONCLUSIONS

It was found that 340 ml min-1 m-2 is likely to represent the lowest suitable Ḋo2 required in neonates to maintain aerobic metabolism during normothermic CPB.

Sepsis: an overview of the signs, symptoms, diagnosis, treatment and pathophysiology

Sepsis is a common phenomenon surrounded by uncertainty and misunderstanding. The urgency for treatment is complicated by the vagueness of signs and symptoms and lack of a conclusive diagnostic test. This article unpicks the signs and symptoms of sepsis with guidance for emergency department nurses who are responsible for assessing patients with potential sepsis. The article also relates monitoring, investigation and treatment expectations to the underlying pathophysiology and refers to the individual and global implications of the condition.

Biomarkers in Pediatric Cardiac Critical Care

OBJECTIVES

In this review, we discuss the physiology, pathophysiology, and clinical role of troponin, lactate, and B-type natriuretic peptide in the assessment and management of children with critical cardiac disease.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSION

Lactate, troponin, and B-type natriuretic peptide continue to be valuable biomarkers in the assessment and management of critically ill children with cardiac disease. However, the use of these markers as a single measurement is handicapped by the wide variety of clinical scenarios in which they may be increased. The overall trend may be more useful than any single level with a persistent or rising value of more importance than an elevated initial value.

[Venous saturation : Between oxygen delivery and consumption]

Venous saturation is an important parameter to assess the ratio between oxygen delivery and oxygen consumption for both intensive care medicine and during perioperative care. Mixed venous saturation (SvO₂) is the most reliable parameter in this setting. Due to the high invasiveness of measuring mixed venous saturation, the less invasive central venous saturation (ScvO₂) has been entrenched for determining the balance of oxygen delivery and consumption. However, central venous saturation is inferior compared to mixed venous saturation as it does not cover the lower part of the body, including splanchnic perfusion. Nevertheless, studies have shown that central venous saturation is a reliable marker for goal-directed therapy in intensive care medicine, especially in patients with septic or hemorrhagic shock. Furthermore, central venous saturation has deep impact as a prognostic factor concerning morbidity and mortality. It has to be mentioned that not only decreased venous saturations but also elevated venous saturations are associated with poor outcome. Besides mixed venous and central venous saturation, intensivists and anesthesiologists focus on the central venous-arterial pCO₂ difference (dCO₂). An elevated dCO₂ is associated with poor outcome in patients after cardiac surgery or patients with sepsis. Yet, further investigations have to be performed to implement the dCO₂ as a reliable marker in daily routine.

The Use of Sodium Bicarbonate in the Treatment of Acidosis in Sepsis: A Literature Update on a Long Term Debate

Introduction. Sepsis and its consequences such as metabolic acidosis are resulting in increased mortality. Although correction of metabolic acidosis with sodium bicarbonate seems a reasonable approach, there is ongoing debate regarding the role of bicarbonates as a therapeutic option. Methods. We conducted a PubMed literature search in order to identify published literature related to the effects of sodium bicarbonate treatment on metabolic acidosis due to sepsis. The search included all articles published in English in the last 35 years. Results. There is ongoing debate regarding the use of bicarbonates for the treatment of acidosis in sepsis, but there is a trend towards not using bicarbonate in sepsis patients with arterial blood gas pH > 7.15. Conclusions. Routine use of bicarbonate for treatment of severe acidemia and lactic acidosis due to sepsis is subject of controversy, and current opinion does not favor routine use of bicarbonates. However, available evidence is inconclusive, and more studies are required to determine the potential benefit, if any, of bicarbonate therapy in the sepsis patient with acidosis.

Effect of pH on the rate of curing and bioadhesive properties of dopamine functionalized poly(ethylene glycol) hydrogels

The remarkable underwater adhesion strategy employed by mussels has inspired bioadhesives that have demonstrated promise in connective tissue repair, wound closure, and local delivery of therapeutic cells and drugs. While the pH of oxygenated blood and internal tissues is typically around 7.4, skin and tumor tissues are significantly more acidic. Additionally, blood loss during surgery and ischemia can lead to dysoxia, which lowers pH levels of internal tissues and organs. Using 4-armed PEG end-capped with dopamine (PEG-D) as a model adhesive polymer, the effect of pH on the rate of intermolecular cross-linking and adhesion to biological substrates of catechol-containing adhesives was determined. Adhesive formulated at an acidic pH (pH 5.7-6.7) demonstrated reduced curing rate, mechanical properties, and adhesive performance to pericardium tissues. Although a faster curing rate was observed at pH 8, these adhesives also demonstrated reduced mechanical and bioadhesive properties when compared to adhesives buffered at pH 7.4. Adhesives formulated at pH 7.4 demonstrated a good balance of fast curing rate, elevated mechanical properties and interfacial binding ability. UV-vis spectroscopy evaluation revealed that the stability of the transient oxidation intermediate of dopamine was increased under acidic conditions, which likely reduced the rate of intermolecular cross-linking and bulk cohesive properties for hydrogels formulated at these pH levels. At pH 8, competing cross-linking reaction mechanisms and reduced concentration of dopamine catechol due to auto-oxidation likely reduced the degree of dopamine polymerization and adhesive strength for these hydrogels. pH plays an important role in the adhesive performance of mussel-inspired bioadhesives and the pH of the adhesive formulation needs to be adjusted for the intended application.

Pharmacokinetics, hemodynamic and metabolic effects of epinephrine to prevent post-operative low cardiac output syndrome in children

Introduction

The response to exogenous epinephrine (Ep) is difficult to predict given the multitude of factors involved such as broad pharmacokinetic and pharmacodynamic between-subject variabilities, which may be more pronounced in children. We investigated the pharmacokinetics and pharmacodynamics of Ep, co-administered with milrinone, in children who underwent open heart surgical repair for congenital defects following cardiopulmonary bypass, including associated variability factors.

Methods

Thirty-nine children with a high risk of low cardiac output syndrome were prospectively enrolled. Ep pharmacokinetics, hemodynamic and metabolic effects were analyzed using the non-linear mixed effects modeling software MONOLIX. According to the final model, an Ep dosing simulation was suggested.

Results

Ep dosing infusions ranged from 0.01 to 0.23 μg.kg^-1.min^-1 in children whose weight ranged from 2.5 to 58 kg. A one-compartment open model with linear elimination adequately described the Ep concentration-time courses. Bodyweight (BW) was the main covariate influencing clearance (CL) and endogenous Ep production rate (q0) via an allometric relationship: CL(BWi) = θ_CL x (BWi)^3/4 and q0(BWi) = θ_q0 x (BWi )^3/4. The increase in heart rate (HR) and mean arterial pressure (MAP) as a function of Ep concentration were well described using an Emax model. The effect of age was significant on HR and MAP basal level parameters. Assuming that Ep stimulated the production rate of plasma glucose, the increases in plasma glucose and lactate levels were well described by turnover models without any significant effect of age, BW or exogenous glucose supply.

Conclusions

According to this population analysis, the developmental effects of BW and age explained a part of the pharmacokinetic and pharmacodynamics between-subject variabilities of Ep administration in critically ill children. This approach ultimately leads to a valuable Ep dosing simulation which should help clinicians to determine an appropriate a priori dosing regimen.

Diagnostic dilemma: rare case of recurrent d-lactic acidosis leading to recurrent acute cardiac failure

d-Lactic acidosis is a rare form of anion gap acidosis and requires a high index of suspicion for appropriate diagnosis and treatment. We report a rare case of short bowel syndrome with recurrent episodes of antibiotic-induced d-lactic acidosis with the presentation of transient severe left ventricular failure. The patient's cardiac function returned to normal with the resolution of acidosis under conservative management and a low carbohydrate diet. d-Lactic acidosis has been known to be associated with only neurological symptoms, and cardiac failure has not been previously reported.

Interstitium: the next diagnostic and therapeutic platform in critical illness

BACKGROUND

For decades we have been testing blood either ex vivo or else placing monitors directly in the bloodstream to "see" what might be going on in tissues. In the last 20 yrs, conceptual and practical advances in interstitial monitoring have begun to challenge traditional approaches. In this review we explore how interstitial monitoring might be used as a platform for future diagnostics and therapy in critical illness.

RESULTS

From a diagnostic perspective, interstitial analysis has been instructive about the pathophysiology of critical illness. Valuable insights have been gained into the pathophysiology of critical illness. To this end, examples from the areas of interstitial oxygenation and acid base, endocrine pathophysiology, and head injury monitoring have been used. From a therapeutic perspective, the main focus has been on antibiotic therapy and an improved understanding of pharmacokinetics and pharmacodynamics in critical illness.

CONCLUSIONS

Monitoring of the interstitium is feasible and can be achieved through minimally invasive techniques. It has improved the understanding of the pathophysiology of critical illness, holds potential in the diagnosis and management of sepsis, may allow early prediction of organ deterioration, and finally offers the possibility of reduction of blood testing and minimizing blood loss. While all of these hold promise, randomized trials will need to be conducted based on interstitial end points rather than plasma end points. This will pave the way for a more rational approach to the therapy of critically ill patients.

Hypoxia--implications for pharmaceutical developments

Cells sense oxygen availability using not only the absolute value for cellular oxygen in regard to its energetic and metabolic functions, but also the gradient from the cell surface to the lowest levels in the mitochondria. Signals are used for regulatory purposes locally as well as in the generation of cellular, tissue, and humoral remodeling. Lowered oxygen availability (hypoxia) is theoretically important in the consideration of pharmacology because (1) hypoxia can alter cellular function and thereby the therapeutic effectiveness of the agent, (2) therapeutic agents may potentiate or protect against hypoxia-induced pathology, (3) hypoxic conditions may potentiate or mitigate drug-induced toxicity, (4) hypoxia may alter drug metabolism and thereby therapeutic effectiveness, and (5) therapeutic agents might alter the relative coupling of blood flow and energy metabolism in an organ. The prototypic biochemical effect of hypoxia is related to its known role as a cofactor in a number of enzymatic reactions, e.g., oxidases and oxygenases, which are affected independently from the bioenergetic effect of low oxygen on energetic functions. The cytochrome P-450 family of enzymes is another example. Here, there is a direct effect of oxygen availability on the conformation of the enzyme, thereby altering the metabolism of drug substrates. Indirectly, the NADH/NAD+ ratio is increased with 10% inspired oxygen, leading not only to reduced oxidation of ethanol but also to reduction of azo- and nitro-compounds to amines and disulfides to sulfhydryls. With chronic hypoxia, many of these processes are reversed, suggesting that hypoxia induces the drug-metabolizing systems. Support for this comes from observations that hypoxia can induce the hypoxic inducible factors which in turn alters transcription and function of some but not all cytochrome P-450 isoforms. Hypoxia is identified as a cofactor in cancer expression and metastatic potential. Thus, the effects of hypoxia play an important role in pharmacology, and the signaling pathways that are affected by hypoxia could become new targets for novel therapy or avenues for prevention.

An evaluation of serial blood lactate measurement as an early predictor of shock and its outcome in patients of trauma or sepsis

Context:

Attainment of hemodynamic parameters to within a normal range may leave patients in compensatory shock. In such patients, serial blood lactate evaluation can be useful in predicting shock.

Aims:

To ascertain the role of serum lactate as a predictor of shock and its outcome in patients of trauma and sepsis.

Settings and Design:

A prospective, non-interventional study.

Materials and Methods:

The study included 50 patients (5 to 60 years old) of trauma admitted within 12 hours of injury and patients of suspected or proven sepsis. Those with chronic medical illnesses, alcohol intoxication, or poisoning were excluded. Blood lactate levels were analyzed at admission and 12, 24, and 36 hours of inclusion with records of corresponding hemodynamic variables, investigations, and interventions. The outcome was recorded as survival or non-survival.

Statistical Analysis Used:

Statistical analysis was done with a student's t test and repeated measure ANOVA (Analysis of Variance).

Results:

An analysis revealed higher mean lactate levels in non-survivors as compared with survivors. Mean lactate levels in non-survivors did not attain normal levels, while that of survivors reached normal levels by 24 hrs in trauma patients and 36 hrs in sepsis patients. The predicted mortality rates by a lactate level >40 mg/dl at admission, 12, 24, and 36 hours were 52.6%, 61.5%, 83.3%, and 100%, respectively for both the subgroups combined. Non-survivors had a higher incidence of MODS (Multi Organ Dysfunction Syndrome).

Conclusions:

Serial lactate values followed over a period of time can be used to predict impending complications or grave outcome in patients of trauma or sepsis. Interventions that decrease lactate values to normal early may improve chances of survival and can be considered effective therapy. Lactate values need to be followed for a longer period of time in critical patients.

The lactate:pyruvate ratio following open cardiac surgery in children

OBJECTIVE

To explore the relationship between lactate:pyruvate ratio, hyperlactataemia, metabolic acidosis, and morbidity.

DESIGN AND SETTING

Prospective observational study in the paediatric intensive care unit (PICU) of a university hospital.

PATIENTS

Ninety-seven children after open cardiac surgery. Most children (94%) fell into low-moderate operative risk categories; observed PICU mortality was 1%.

INTERVENTIONS

Blood was sampled on admission for acid-base analysis, lactate, and pyruvate. Metabolic acidosis was defined as standard bicarbonate lower than 22 mmol/l, raised lactate as higher than 2 mmol/l, and raised lactate:pyruvate ratio as higher than 20.

MEASUREMENTS AND RESULTS

Median cardiopulmonary bypass and aortic cross-clamp times were 80 and 46 min. Metabolic acidosis occurred in 74%, hyperlactataemia in 42%, and raised lactate:pyruvate ratio in 45% of children. In multivariate analysis lactate:pyruvate ratio increased by 6.4 in children receiving epinephrine infusion and by 0.4 per 10 min of aortic cross-clamp. Duration of inotropic support increased by 0.29 days, ventilatory support by 0.27 days, and PICU stay by 0.42 days, for each 1 mmol/l increase in lactate. Neither standard bicarbonate nor lactate:pyruvate ratio were independently associated with prolongation of PICU support.

CONCLUSIONS

Elevated lactate:pyruvate ratio was common in children with mild metabolic acidosis and low PICU mortality. Hyperlactataemia, but not elevated lactate:pyruvate ratio or metabolic acidosis, was associated with prolongation of PICU support. Routine measurement of lactate:pyruvate ratio is not warranted for children in low-moderate operative risk categories.

The role of hypoxia inducible factor-1 in cell metabolism--a possible target in cancer therapy

In many cancer types, intratumoural hypoxia is linked to increased expression and activity of the transcription factor hypoxia-inducible factor (HIF-1alpha), which is associated with poor patient prognosis. This increased the interest in HIF-1alpha as a cancer drug target. Further, HIF-1alpha has also a central role in the adaptive cellular programme responding to hypoxia in normal tissues. Many of the HIF-1alpha-regulated genes encode enzymes of metabolic pathways. Therefore, studying the link and the feedback mechanisms between metabolism and HIF-1alpha is of major importance to find new and specific therapeutic strategies.

Normal serum alanine concentration differentiates transient neonatal lactic acidemia from an inborn error of energy metabolism

BACKGROUND

Elevated blood lactate levels are common in the critically ill neonate; however, sometimes they are difficult to interpret. Persistent or recurrent lactic acidemia might point to an inborn error of metabolism, like disturbances of the oxidative phosphorylation. Chronic lactic acidemia results in increased serum alanine levels. Serum alanine levels in newborns with transient lactic acidemia have not yet been studied.

OBJECTIVE

We designed a pilot study to evaluate the use of serum alanine levels as an additional metabolic marker to differentiate the transient effect of circulatory failure from a possible mitochondrial dysfunction.

METHODS

We prospectively evaluated 10 newborns with transient lactic acidemia after mild dysoxia, and 10 newborns with recurrent lactic acidemia consecutively diagnosed with a disorder in oxidative phosphorylation.

RESULTS

No significant serum alanine level elevation was found in transient lactic acidemia. Increased serum alanine was a sensitive marker in mitochondrial dysfunction.

CONCLUSIONS

We propose to measure the serum alanine level in hypotonic newborns with lactic acidemia to facilitate the decision making in further diagnostics and management.

Too much lactate or too little liver?

We describe a 67-year-old woman with cholangiocarcinoma who was scheduled for cholecystectomy, trisegmentectomy, bile duct resection, and regional lymphadenectomy. Her case was complicated by hyperlactatemia, sepsis, and multiorgan failure. The discussion reviews the possible causes of the hyperlactatemia and reviews measures that could be used to reduce this risk.

Adjunctive therapies in sepsis: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for adjunctive therapies in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and to improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Glycemic control (maintenance of glucose <150 mg/dL) is recommended. The beneficial effect of glycemic control appears to be related control of glucose and not the administration of insulin. Glycemic control should be combined with a nutritional protocol. The dialysis dose is important in sepsis-induced acute renal failure. Continuous hemofiltration offers easier management of fluid balance in hemodynamically unstable septic patients but in the absence of hemodynamic instability is equivalent to intermittent hemodialysis. It is uncertain whether high-volume hemofiltration improves prognosis in sepsis. Bicarbonate therapy is not recommended for the purpose of improving hemodynamics or reducing vasopressor requirements in the presence of lactic academia and pH >7.15.

The cellular fate of glucose and its relevance in type 2 diabetes

Type 2 diabetes is a complex disorder with diminished insulin secretion and insulin action contributing to the hyperglycemia and wide range of metabolic defects that underlie the disease. The contribution of glucose metabolic pathways per se in the pathogenesis of the disease remains unclear. The cellular fate of glucose begins with glucose transport and phosphorylation. Subsequent pathways of glucose utilization include aerobic and anaerobic glycolysis, glycogen formation, and conversion to other intermediates in the hexose phosphate or hexosamine biosynthesis pathways. Abnormalities in each pathway may occur in diabetic subjects; however, it is unclear whether perturbations in these may lead to diabetes or are a consequence of the multiple metabolic abnormalities found in the disease. This review is focused on the cellular fate of glucose and relevance to human type 2 diabetes.

Mortality and the nature of metabolic acidosis in children with shock

HYPOTHESIS

Mortality in children with shock is more closely related to the nature, rather than the magnitude (base deficit/excess), of a metabolic acidosis.

OBJECTIVE

To examine the relationship between base excess (BE), hyperlactataemia, hyperchloraemia, 'unmeasured' strong anions, and mortality.

DESIGN

Prospective observational study set in a multi-disciplinary Paediatric Intensive Care Unit (PICU).

PATIENTS

Forty-six children, median age 6 months (1.5-14.4), median weight 5 kg (3.2-8.8), admitted to PICU with shock.

INTERVENTIONS

Predicted mortality was calculated from the paediatric index of mortality (PIM) score. The pH, base excess, serum lactate, corrected chloride, and 'unmeasured' strong anions (Strong Ion Gap) were measured or calculated at admission and 24 h.

MEASUREMENTS AND RESULTS

Observed mortality ( n=16) was 35%, with a standardised mortality ratio (SMR) of 1.03 (95% CI 0.71-1.35). There was no significant difference in admission pH or BE between survivors and nonsurvivors. There was no association between elevation of 'unmeasured' anions and mortality, although there was a trend towards hyperchloraemia in survivors ( P=0.08). Admission lactate was higher in nonsurvivors (median 11.6 vs 3.3 mmol/l; P=0.0003). Area under the mortality receiver operating characteristic curve for lactate was 0.83 (955 CI 0.70-0.95), compared to 0.71 (95% CI 0.53-0.88) for the PIM score. Admission lactate level >5 mmol/l had maximum diagnostic efficiency for mortality, with a likelihood ratio of 2.0.

CONCLUSION

There is no association between the magnitude of metabolic acidosis, quantified by the base excess, and mortality in children with shock. Hyperlactataemia, but not elevation of 'unmeasured' anions, is predictive of a poor outcome.

Septic shock

Infection is problematic because it affects many patients (adults and children), is a major cause of death in intensive care units (ICU) worldwide, and uses a large amount of hospital resources. The mortality rate among patients with septic shock varies but approximates 40% in infected patients admitted to ICUs. Because of the large number of adults dying of sepsis, many resources are expended. Children are physiologically different from adults, but nonetheless, many similarities exist with respect to the response to septic shock.