Serum Lactate Concentrations Research Articles

Description of a novel fatigue syndrome of finished feedlot cattle following transportation.

Ensuring appropriate animal welfare is a high priority for the beef industry, and poorly defined abnormalities in the mobility of cattle at abattoirs have gained considerable attention recently. During the summer of 2013, abattoirs throughout the United States reported concerns about nonambulatory or slow and difficult to move cattle and cattle that sloughed hoof walls. This report describes various cattle that developed these mobility problems soon after arrival at an abattoir. Affected cattle had various clinical signs including tachypnea with an abdominal component to breathing, lameness, and reluctance to move. Some cattle sloughed 1 or more hoof walls while in lairage pens and were euthanized. Other cattle recovered after being rested overnight. Affected cattle had serum lactate concentration and creatine kinase activity increased from reference ranges. Histologic findings included diffuse necrosis of the epidermal laminae with degenerate collagen and perivascular infiltration of neutrophils in the underlying deep dermis, and were similar for digits that had and had not sloughed the hoof wall. With the exception of the sloughed hoof walls, the clinical signs and serum biochemical abnormalities observed in affected cattle were similar to those observed in pigs with fatigued pig syndrome, and we propose that fatigued cattle syndrome be used to describe such cattle. Although anecdotal evidence generated concern that cattle fed the β-adrenergic receptor agonist zilpaterol hydrochloride were at greater risk of developing mobility problems, compared with cattle not fed zilpaterol, this condition is likely multifactorial. Strategies to prevent this condition are needed to protect the welfare of cattle.

Effect of High-Intensity Interval Training (HIT) for 4 Weeks with and without L-Arginine Supplementation on the Performance of Women’s Futsal Players

Aims: In recent years, consumption of nutrition supplements such as LArginine has increased in athletes in order to increase efficiency and reduce fatigue. The purpose of the present study was to examine the effects of 4 weeks of high-intensity interval training (HIT) with and without L-Arginine supplementation on anaerobic and aerobic performance in women’s futsal players. Materials & Methods: In this research study (2013), 20 healthy women futsal players in Kermanshah City, Iran, were selected by available sampling method. Subjects were randomly divided into two groups; training-supplement (n=10) and training-placebo (n=10). Both groups, in addition to futsal specific training, performed RAST (anaerobic sprint test) test as high-intensity interval training protocol, 2 sessions per week for 4 weeks. Before and after the training protocol, subjects performed Bruce and RAST tests in order to measure aerobic and anaerobic power, respectively. Blood samples were collected 30 seconds after the RAST test to measure the levels of serum lactate concentration. All data were analyzed using independent T and paired T tests. Findings: After the training, both groups showed significant increasing in VO2max and anaerobic power (p<0.05) and significant decreasing in blood lactate concentrations (p<0.05); percentage of changes were greater for the first than the second group in all three factors. Conclusion: Using high-intensity interval training in combination with LArginine lead to improvement of aerobic and anaerobic fitness in women futsal players.

The Use of the Ratio between the Veno-arterial Carbon Dioxide Difference and the Arterial-venous Oxygen Difference to Guide Resuscitation in Cardiac Surgery Patients with Hyperlactatemia and Normal Central Venous Oxygen Saturation.

Background:After cardiac surgery, central venous oxygen saturation (ScvO2) and serum lactate concentration are often used to guide resuscitation; however, neither are completely reliable indicators of global tissue hypoxia. This observational study aimed to establish whether the ratio between the veno-arterial carbon dioxide and the arterial-venous oxygen differences (P(v−a)CO2/C(a−v)O2) could predict whether patients would respond to resuscitation by increasing oxygen delivery (DO2).Methods:We selected 72 patients from a cohort of 290 who had undergone cardiac surgery in our institution between January 2012 and August 2014. The selected patients were managed postoperatively on the Intensive Care Unit, had a normal ScvO2, elevated serum lactate concentration, and responded to resuscitation by increasing DO2 by >10%. As a consequence, 48 patients responded with an increase in oxygen consumption (VO2) while VO2 was static or fell in 24.Results:At baseline and before resuscitative intervention in postoperative cardiac surgery patients, a P(v−a)CO2/C(a−v)O2 ratio ≥1.6 mmHg/ml predicted a positive VO2 response to an increase in DO2 of >10% with a sensitivity of 68.8% and a specificity of 87.5%.Conclusions:P(v−a)CO2/C(a−v)O2 ratio appears to be a reliable marker of global anaerobic metabolism and predicts response to DO2 challenge. Thus, patients likely to benefit from resuscitation can be identified promptly, the P(v−a)CO2/C(a−v)O2 ratio may, therefore, be a useful resuscitation target.

Prediction of ATLS hypovolemic shock class in rats using the perfusion index and lactate concentration.

It is necessary to quickly and accurately determine Advanced Trauma Life Support (ATLS) hemorrhagic shock class for triage in cases of acute hemorrhage caused by trauma. However, the ATLS classification has limitations, namely, with regard to primary vital signs. This study identified the optimal variables for appropriate triage of hemorrhage severity, including the peripheral perfusion index and serum lactate concentration in addition to the conventional primary vital signs. To predict the four ATLS classes, three popular machine learning algorithms with four feature selection methods for multicategory classification were applied to a rat model of acute hemorrhage. A total of 78 anesthetized rats were divided into four groups for ATLS classification based on blood loss (in percent). The support vector machine one-versus-one model with the Kruskal-Wallis feature selection method performed best, with 80.8% accuracy, relative classifier information of 0.629, and a kappa index of 0.732. The new hemorrhage-induced severity index (lactate concentration/perfusion index), diastolic blood pressure, mean arterial pressure, and the perfusion index were selected as the optimal variables for predicting the four ATLS classes by support vector machine one-versus-one with the Kruskal-Wallis method. These four variables were also selected for binary classification to predict ATLS classes I and II versus III and IV for blood transfusion requirement. The suggested ATLS classification system would be helpful to first responders by indicating the severity of patients, allowing physicians to prepare suitable resuscitation before hospital arrival, which could hasten treatment initiation.

Intraoperative change of lactate level is associated with postoperative outcomes in pediatric cardiac surgery patients: retrospective observational study.

BackgroundA change of serum lactate concentrations appeared to be useful for predicting outcomes in various acute ill settings. However, there is little information on intraoperative change of lactate level in pediatric cardiac surgery patients.MethodsWe conducted a retrospective observational study of 459 children who received pediatric cardiac surgery to determine the association between change of lactate level after cardiopulmonary bypass (CPB) and patient prognosis (length of ICU stay and incidence of postoperative serious adverse events (SAEs)). We defined change of lactate level after CPB (LAC⊿) as (final lactate level measurement in the operating room) – (lactate level measured at the end of CPB). To study the independent association of LAC⊿ with length of ICU stay, we used linear regression model.ResultsThere were 1145 lactate measurements after CPB in this study cohort. After weaning from CPB, the serum lactate levels significantly increased from 2.1 mmol/L to 2.5 mmol/L (p < 0.001). Patients with higher LAC⊿ had significantly longer stay in ICU (p = 0.017) and higher incidence of SAEs (p = 0.002). In multivariate linear regression analysis, higher LAC⊿ showed a significant independent association with longer length of ICU stay.ConclusionsIncreased lactate level after CPB was associated with the longer duration of ICU stay and increased risk of postoperative SAEs in pediatric cardiac surgery patients. Future studies should be conducted to determine the clinical utility of intraoperative trend of lactate levels.Electronic supplementary materialThe online version of this article (doi:10.1186/s12871-015-0007-y) contains supplementary material, which is available to authorized users.

Effects of therapeutic hypothermia and kinetics of serum protein S100B after cardiopulmonary resuscitation

Introduction. Post-resuscitation care is regulated by international guidelines. A milestone of these is the application of therapeutic hypothermia (TH). The aims of our study were: to determine the 30-day-mortality for our patients, to monitor the efficacy and effects of TH, and to investigate serum protein S100B – as an early prognostic marker.Materials and Methods. In our study, 57 patients, treated after cardiopulmonary resuscitation (CPR) on a multidisciplinary intensive care unit, were included. Patients were divided into groups who received and who didn’t receive TH. 30-day-mortality was determined as an end-point. Effects of TH were monitored using statistical analysis according to clinical parameters and laboratory tests. Serum protein S100B levels were measured with ELISA technique on 20 randomised patients atadmission and the 1st, 3rd and 5th day after CPR. Results. Total 30-day-mortality was 74%. TH did not reduced the 30-day-mortality (73% vs. 74%, p>0.05). We found a significant correlation between TH and serum lactate concentration after admission (0h,p=0.006) and at 12 (p=0.045) and 36 (p=0.049) hours after CPR. On the3rd (p=0.005) and 4th (p=0.043) day after CPR, as a result of TH, platelet count was significantly higher compared to normothermic samples. There was no significant difference in protein S100B levels between the normothermic and TH group and protein S100B levels did not correlate with 30-day-mortality.Conclusion. Despite recommendations of international guidelines, we cannot prove the beneficial effect of TH, or a correlation of protein S100B levels with a positive outcome.

Does Inferior-Vena-Cava Collapsibility Correlate with Fluid Regimen and Outcome in Patients Undergoing Liver Resection?

Aim: We retrospectively investigated whether inferior-vena-cava diameter variations due to mechanical ventilation, correlates with fluid regimen and outcome in hepatic resection. Methods: We analyzed data from 91 cases of liver resection during which inferior vena cava collapsibility was measured in duplicate, before and after the resection phase of the operation (IVCI1 and IVCI2). IVCI was calculated according to the following formula: [IVCDmax-IVCDmin]/[0.5 × (IVCDmax+IVCDmin)], where IVCDmax and IVCDmin stand for the maximal and minimal IVCD within one a respiratory cycle. IVCI variation (ΔIVCI) was defined as: (IVCI pre-resection-IVCI post-resection)/IVCI pre-resection. Fluid management focused to maintain CVP <6 mmHg during the parenchymal dissection in an effort to reduce the backflow bleeding and limit the blood loss. Therefore, fluid administration included a volume input 3-5 ml/kg/h of crystalloid solutions from the induction of anesthesia until parenchymal dissection was concluded. Additional fluid administration was at the judgment of the anesthesiologist. Then we searched for any correlation between IVCI and other hemodynamic parameters, fluid regimen administration and the post-operative outcome. Results: Among 91 patients enrolled in the study, 57 (63%) were male and 34 (37%) female aged from 34 to 85 years (median 62 years). The median ASA was 2 (range 1-3). The median operation time was 374 min (range 150-720). Liver transaction was accomplished employing the Pringle maneuver and the median total liver ischemic time was 82 min (range 9-182). After liver resection ending many variables differed significantly from starting values: IVCI from 0.26 ± 0.21 to 0.18 ± 0.16 (p<0.001); HR from 68 ± 14 to 78 ± 13 bpm (p<0.001); CI from 2.6 ± 0.7 to 3.0 ± 0.8 L/min/m2 (p<0.001). All BGA values changed significantly (p<0.001). Serum lactate concentration showed a significant increase during the parenchymal dissection changing from 0.95 ± 0.5 to 4.1 ± 2.0 mmol/L (p<0.001). Serum hemoglobin lowered from 11.3 ± 1.7 g/dl to 9.8 ± 1.8 g/dl (p<0.001). In contrast, CVP and SVV did not change significantly. Both IVCI1 and IVC2 showed a weak correlation with CI (r=-0.166 and r=-0.087), CVP (r=-0.049 and r=-0.083) and SVV (r=0.138 and r=0.121). According to postoperative outcome patients were divided in two groups: Group 1 (complicated) and Group 2 (non-complicated). The IVCI resulted not significantly different between two groups (0.12 ± 0.11 vs 0.16 ± 0.13; p=0.105) which were homogeneous for global fluid regimen (7.25 ± 2.63 ml/kg/h vs 7.98 ± 2.93 ml/kg/h; p=0.341). Conclusions: Although retrospectively, it seems clear that, during hepatic resection, IVCI is not sensible to fluid administration and is not correlated with postoperative outcome.

Incidence and risk factors of linezolid-induced lactic acidosis

The use of linezolid has increased with the emergence of multidrug-resistant bacteria. Serum lactic acidosis has been reported as a serious side effect of linezolid use, therefore we evaluated the incidence and characteristics of linezolid-related lactic acidosis. Patients admitted to an 860-bed university hospital were enrolled. The patients were divided into two groups, those who used linezolid and those who used teicoplanin (control group). The study was conducted by review of the medical charts. Seventy-two patients were included in the linezolid group. The control group comprised 72 patients matched to those in the linezolid group for age and indication for antibiotic use. Lactic acidosis occurred in five cases (6.8%) in the linezolid group. None of the patients who used teicoplanin developed lactic acidosis, which was a comparable result. The median change in anion gap in the linezolid group was -0.8 mmol/l (interquartile range (IQR) -3.55 to 1.28 mmol/l), which was significantly higher than in the teicoplanin group, 0.05 mmol/l (IQR -1.75 to 2.3 mmol/l) (p=0.026). The number of increased anion gap events in patients who used linezolid for more than 6 weeks was higher than in the group who used linezolid for less than 6 weeks (p=0.0014). However, no statistically significant difference was observed according to age, estimated glomerular filtration rate, or diabetes. Linezolid showed an association with treatment-related lactic acidosis. A longer duration of linezolid use (>6 weeks) was one of the risk factors for metabolic acidosis. We suggest checking serum lactate concentrations regularly, especially in those on long-term use.

Pretransplant and perioperative predictors of early heart transplantation outcomes.

AimTo identify predictors of 3-month mortality after heart transplantation in a Croatian academic center.MethodsA retrospective review of institutional database identified 117 heart transplantations from January 2008 to July 2014. Two children <14 years were excluded from the study. The remaining 115 patients were dichotomized into survivors and non-survivors adjudicated at 3-months postoperatively, and their demographic, clinical, and longitudinal hemodynamic data were analyzed.Results3-month survival after heart transplantation was 86%. Non-survivors were older (59 ± 8 vs 50 ± 14 years, P = 0.009), more likely to have previous cardiac surgery (44% vs 19%; odds ratio [OR] 3.28, 95% confidence interval [CI] 1.08-9.90; P = 0.029), lower body mass index (BMI) (25 ± 4 vs 28 ± 2 kg/m2, P = 0.001), and be diabetics (44% vs 23%; OR 2.57, 95% CI 0.86-7.66; P = 0.083). Creatinine clearance was marginally superior among survivors (59 ± 19 vs 48 ± 20 mL/min, P = 0.059). Donor age and sex did not affect outcomes. Non-survivors were more likely to have had ischemic cardiomyopathy (69% vs 32%, P = 0.010). Postoperative utilization of epinephrine as a second line inotropic agent was a strong predictor of mortality (63% vs 7%; OR 21.91; 95% CI 6.15-78.06; P < 0.001). Serum lactate concentrations were consistently higher among non-survivors, with the difference being most pronounced 2 hours after cardiopulmonary bypass (9.8 ± 3.5 vs 5.2 ± 3.2 mmol/L, P < 0.001). The donor hearts exhibited inferior early hemodynamics in non-survivors (cardiac index 3.0 ± 1.0 vs 4.0 ± 1.1 L/min/m2, P = 0.001), stroke volume (49 ± 24 vs 59 ± 19 mL, P = 0.063), and left and right ventricular stroke work indices (18 ± 8 vs 30 ± 11 g/beat/m2, P < 0.001 and 5 ± 3 vs 7 ± 4 g/beat/m2, P = 0.060, respectively). Non-survivors were more likely to require postoperative re-sternotomy (50% vs 12%; OR 7.25, 95% CI 2.29-22.92; P < 0.001), renal replacement therapy (RRT) (69% vs 9%; OR 22.00, 95% CI 6.24-77.54; P < 0.001), and mechanical circulatory assistance (MCS) (44% vs 5%; OR 14.62, 95% CI 3.84-55.62; P < 0.001). Binary logistic regression revealed recipient age (P = 0.024), serum lactates 2 hours after CPB (P = 0.007), and epinephrine use on postoperative day 1 (P = 0.007) to be independently associated with 3-month mortality.ConclusionPretransplant predictors of adverse outcome after heart transplantation were recipient age, lower BMI, ischemic cardiomyopathy, reoperation and diabetes. Postoperative predictors of mortality were inferior donor heart hemodynamics, epinephrine use, and serum lactate concentrations. Non-survivors were more likely to require re-sternotomy, MCS, and RRT.

Exercise in a hot environment influences plasma anti-inflammatory and antioxidant status in well-trained athletes

Exercise in thermally stressful environmental conditions can enhance oxidative stress. We sought to measure the plasma antioxidant defenses and cytokine response together with oxidative damage post-exercise in a temperate versus a hot environment. The plasma concentrations of vasoactive endothelin-1 and vascular angiogenic growth factor were also evaluated. Male athletes (n=9) volunteered to participate. The athletes randomly performed two bouts of treadmill exercise of 45min at 75–80% of maximal oxygen uptake in a climatic-controlled chamber under two different conditions: temperate environment (10–12°C, 40–55% humidity) and hot, humid environment (30–32°C, 75–78% humidity). Venous blood samples were obtained immediately pre- and post-bout and on recovery after 2h. Serum glucose, malondialdehyde and lactate concentrations were significantly increased post-exercise in hot but maintained in the temperate environment; these post-exercise values were significantly higher after exercise in hot than in temperate. Urinary 8-hydroxy-2′-deoxyguanosine concentration, plasma phosphocreatine kinase and catalase activities, creatinine and monocyte chemoattractant protein-1, and interleukin-6 significantly increased post-exercise in hot but maintained in temperate environment. The post-exercise circulating values of antioxidant enzyme paraoxonase-1 and endothelin were significantly higher in the hot than in temperate environment. Exercise in a hot and humid environment resulted in mild hyperthermia with elevated perceived exertion and thermal stress. Hyperthermic environment induced hyperglycemia, lactatecidemia and more cellular and oxidative damage than exercise in a temperate environment but also induced a post-exercise antioxidant and anti-inflammatory response in plasma. These results suggest that environmental temperature needs to be taken into account when evaluating exercise-related oxidative stress and inflammation.

A Randomized Controlled Study on the Effects of Acetate‐Free Biofiltration on Organic Anions and Acid‐Base Balance in Hemodialysis Patients

Metabolic acidosis correction is achieved by the transfer of bicarbonate and other buffer anions in dialysis. The aim of this study was to evaluate changes in the main anions of intermediary metabolism on standard hemodiafiltration (HDF) and on acetate-free biofiltration (AFB). A prospective, in-center, crossover study was carried out with 22 patients on maintenance dialysis. Patients were randomly assigned to start with 12 successive sessions of standard HDF with bicarbonate (34 mmol/L) and acetate dialysate (3 mmol/L) or 12 successive sessions of AFB without base in the dialysate. Acetate increased significantly during the standard HDF session from 0.078 ± 0.062 mmol/L to 0.156 ± 0.128 mmol/L (P < 0.05) and remained unchanged at 0.044 ± 0.034 mmol and 0.055 ± 0.028 mmol/L in AFB modality. Differences in the acetate levels were observed at two hours (P < 0.005), at the end (P < 0.005) and thirty minutes after the session between HDF and AFB (P < 0.05). There were significantly more patients above the normal range in HDF group than AFB group (68.1% vs 4.5% P < 0.005) postdialysis and 30 minutes later. Serum lactate and pyruvate concentrations decreased during the sessions without differences between modalities. Citrate decreased only in the AFB group (P < 0.05). Acetoacetate and betahydroxybutyrate increased in both modalities, but the highest betahydroxybutyrate values were detected in HDF (P < 0.05). The sum of postdialysis unusual measured organic anions (OA) were higher in HDF compared to AFB (P < 0.05). AFB achieves an optimal control of acid-base equilibrium through a bicarbonate substitution fluid. It also prevents hyperacetatemia and restores internal homeostasis with less production of intermediary metabolites.

Serial hemodynamic measurements in post-cardiac arrest cardiogenic shock treated with therapeutic hypothermia.

Mortality from cardiogenic shock complicating acute myocardial infarction (MI) remains high despite contemporary treatment. Therapeutic Hypothermia (TH) offers cardiovascular and systemic effects that may prove beneficial in this population, however, current data are limited. This study sought to evaluate the effect of therapeutic hypothermia on serial hemodynamics obtained in subjects with post-cardiac arrest cardiogenic shock. We analyzed serial hemodynamics of 14 consecutive patients with cardiogenic shock after cardiac arrest treated with TH. Study inclusion required baseline hemodynamics obtained prior to initiation of TH confirming cardiogenic shock defined as cardiac index ≤2.2 L/min/m(2) with a systolic blood pressure of ≤90 mmHg, a vasopressor requirement, or need for mechanical circulatory support. In our 14 patients, the mean age was 58 ± 13.1 years, mean ejection fraction was 21 ± 8%, six had an acute MI, 12 required vasopressors, and 10 required mechanical support prior to initiation of TH. When compared to baseline, patients had significant improvements in Fick cardiac index, mixed venous O2 saturations, and serum lactate concentrations while heart rate was reduced following initiation of TH. There was no significant change in mean arterial pressure, however vasopressor requirement was reduced. In patients with cardiogenic shock following cardiac arrest, initiation of TH was associated with favorable changes in invasive hemodynamics suggesting safety in this population. Given potential for favorable hemodynamic and systemic effects of TH in cardiogenic shock, further prospective study of TH as a potentially novel adjunctive therapy to early reperfusion in post-MI cardiogenic shock should be considered.

SERUM LACTATE IS A USEFUL PREDICTOR OF DEATH IN SEVERE SEPSIS AND SEPTIC SHOCK

Article type Review article Article history The severe sepsis and septic shock are as common and lethal that emergency physicians routinely confront. Actually, more than two thirds of sepsis patients present initially to the ED. Only a few laboratory tests for markers of sepsis are currently available. The serum lactate level can help in determining prognosis and to risk-stratify patients with severe sepsis. This independent review of the literature includes 83 studies published in all electronic-based database such as Elsevier, PubMed, and SID during the last 18 years (40-320 patients in each). Data gathered from English language articles and books published between 1995 and 2013. The serum lactate concentrations measured in almost all patients with severe sepsis raised at admission and were higher in patients who had the worst outcomes such as higher Apache-II and SOFA score. Serum lactate was associated with mortality independent of clinically apparent organ dysfunction and shock in patients with severe sepsis admitted to the emergency department and intensive care unit. This review focuses on the association between initial and serial serum lactate level and mortality in patients presenting to the emergency department with severe sepsis.

Metabolomic analysis of amino acid and energy metabolism in rats supplemented with chlorogenic acid.

This study was conducted to investigate effects of chlorogenic acid (CGA) supplementation on serum and hepatic metabolomes in rats. Rats received daily intragastric administration of either CGA (60mg/kg body weight) or distilled water (control) for 4weeks. Growth performance, serum biochemical profiles, and hepatic morphology were measured. Additionally, serum and liver tissue extracts were analyzed for metabolomes by high-resolution (1)H nuclear magnetic resonance-based metabolomics and multivariate statistics. CGA did not affect rat growth performance, serum biochemical profiles, or hepatic morphology. However, supplementation with CGA decreased serum concentrations of lactate, pyruvate, succinate, citrate, β-hydroxybutyrate and acetoacetate, while increasing serum concentrations of glycine and hepatic concentrations of glutathione. These results suggest that CGA supplementation results in perturbation of energy and amino acid metabolism in rats. We suggest that glycine and glutathione in serum may be useful biomarkers for biological properties of CGA on nitrogen metabolism in vivo.

The impact of racing on serum concentrations of acute-phase proteins in racing dromedary camels

This study was designed to evaluate the impact of racing on serum concentrations of haptoglobin (Hp) and serum amyloid A (SAA) acute-phase proteins (APPs) in racing camels (Camelus dromedarius). Blood samples were collected 24 h prior to a 5-km race (T0) and within 2 h of completion of the race (T1). The white blood cell counts (WBCCs) were determined in EDTA blood samples. In the serum samples, the concentrations of cortisol, lactate, Hp, and SAA were determined within 2 weeks of sampling. Compared to pre-race values, the post-race WBCCs did not differ significantly. The mean serum cortisol concentrations increased significantly post-race; however, the mean serum lactate concentrations decreased significantly following the race. The serum concentrations of Hp and SAA APPs increased significantly post-race. The elevations of Hp and SAA suggest that an acute-phase reaction occurred in the camels after the race, thus shedding light on the impact of racing on the release of APPs.

Effect of synthetic colloid administration on hemodynamic and laboratory variables in healthy dogs and dogs with systemic inflammation.

To compare the effects of administering equal volumes of isotonic crystalloids and synthetic colloids on hemodynamic and laboratory variables in healthy dogs and dogs with systemic inflammation. Randomized, placebo-controlled, blinded study. Comparative clinical research facility. Sixteen adult purpose-bred Beagles. Dogs were first randomized to receive either lipopolysaccharide (LPS; 5 μg/kg, IV) or an equal volume of placebo (0.9% NaCl, IV). Dogs were then randomized into 1 of 2 groups receiving fluid resuscitation with either 40 mL/kg IV isotonic crystalloid (0.9% NaCl) or synthetic colloid (tetrastarch). After a 14-day washout, the study was repeated such that dogs received the opposite treatment (LPS or placebo) and the same resuscitation fluid regimen. Vital signs (heart rate (HR), oscillometric blood pressure) were measured and blood samples were collected for PCV, total plasma protein (TPP), serum lactate concentration, and colloid osmotic pressure (COP) measurements. Healthy (placebo) dogs had similar decreases in PCV and TPP after administration of either fluid. Tetrastarch administration was associated with a larger increase in HR, systolic blood pressure, and mean blood pressure. Dogs with systemic inflammation had similar increases in systolic blood pressure and decreases in PCV, TPP, and lactate after administration of either fluid. Tetrastarch administration caused greater immediate increase in HR and mean blood pressure compared to 0.9% NaCl. In all dogs, 0.9% NaCl administration decreased COP and tetrastarch administration increased COP. Resuscitation with equal volumes of 0.9% NaCl and tetrastarch caused similar changes in hemodynamic and laboratory variables in dogs with LPS-induced systemic inflammation; however, larger increases in HR and blood pressure were seen within the first 2 hours following tetrastarch administration compared to 0.9% NaCl. Tetrastarch administration increased COP in all dogs, despite a decrease in TPP.

α1‐Syntrophin–deficient mice exhibit impaired muscle force recovery after osmotic shock

α1-syntrophin, a member of the dystrophin complex, recruits membrane molecules, including aquaporin-4, at the sarcolemma. The physiological functions of α1-syntrophin are poorly understood. We examined the physiological characteristics of α1-syntrophin-deficient muscles under osmotic stress conditions to test the possibility that mutant muscles are less tolerant of osmotic shock. Isolated muscle bundles from mutant mice showed markedly reduced force production after hypo-osmotic shock. In addition, the mutant muscle bundles showed delayed recovery of specific gravity after being exposed to hypo-osmotic conditions. Two consecutive exercise tests on the treadmill revealed their performance in the second test was significantly lower than for wild-type mice. Furthermore, mutant mice had higher serum lactate concentrations after treadmill exercise. Although the lack of α1-syntrophin from the sarcolemma does not lead to muscle degeneration, our results suggest that it may be partly involved in the pathophysiology of dystrophin-deficient Duchenne muscular dystrophy.

Severe lactic acidosis in critically ill patients with acute kidney injury treated with renal replacement therapy

PurposeSevere lactic acidosis (SLA) is frequent in intensive care unit (ICU) patients with acute kidney injury (AKI) treated with renal replacement therapy (RRT). The aim of the study is to describe the epidemiology of SLA in this setting. Materials and methodsAn observational single-center cohort analysis was performed on AKI patients treated with RRT. At initiation of RRT, SLA patients (serum lactate concentration >5 mmol/L and pH <7.35) were compared with non-SLA patients. ResultsOf the 454 patients dialyzed during the study period, 342 patients matched inclusion criteria (116 with and 226 patients without SLA). In SLA patients, lactate stabilized/decreased in 69.7% at 4 hours (P = .001) and in 81.8% during the period of 4 to 24 hours (P < .001) after initiation of RRT. Mortality during this 24-hour period was 31.0%. Intensive care unit mortality was 83.6% compared with 47.3% in non-SLA patients. Initial lactate concentration was not related to ICU mortality in SLA patients. ConclusionsSevere lactic acidosis was frequent in AKI patients treated with RRT. Severe lactic acidosis patients were more severely ill and had higher mortality compared with patients without. During the first 24 hours of RRT, a correction of lactate concentration and acidosis was observed. In SLA patients, lactate concentration at initiation of RRT was not able to discriminate between survivors and nonsurvivors.

Effects of Pre- or Post-Exercise Low-Level Laser Therapy (830 nm) on Skeletal Muscle Fatigue and Biochemical Markers of Recovery in Humans: Double-Blind Placebo-Controlled Trial

The purpose of this study was to investigate the effect of low-level laser therapy (LLLT) before and after exercise on quadriceps muscle performance, and to evaluate the changes in serum lactate and creatine kinase (CK) levels. The study was randomized, double blind, and placebo controlled. A sample of 27 healthy volunteers (male soccer players) were divided into three groups: placebo, pre-fatigue laser, and post-fatigue laser. The experiment was performed in two sessions, with a 1 week interval between them. Subjects performed two sessions of stretching followed by blood collection (measurement of lactate and CK) at baseline and after fatigue of the quadriceps by leg extension. LLLT was applied to the femoral quadriceps muscle using an infrared laser device (830 nm), 0.0028 cm(2) beam area, six 60 mW diodes, energy of 0.6 J per diode (total energy to each limb 25.2 J (50.4 J total), energy density 214.28 J/cm(2), 21.42 W/cm(2) power density, 70 sec per leg. We measured the time to fatigue and number and maximum load (RM) of repetitions tolerated. Number of repetitions and time until fatigue were primary outcomes, secondary outcomes included serum lactate levels (measured before and 5, 10, and 15 min after exercise), and CK levels (measured before and 5 min after exercise). The number of repetitions (p=0.8965), RM (p=0.9915), and duration of fatigue (p=0.8424) were similar among the groups. Post-fatigue laser treatment significantly decreased the serum lactate concentration relative to placebo treatment (p<0.01) and also within the group over time (after 5 min vs. after 10 and 15 min, p<0.05 both). The CK level was lower in the post-fatigue laser group (p<0.01). Laser application either before or after fatigue reduced the post-fatigue concentrations of serum lactate and CK. The results were more pronounced in the post-fatigue laser group.

Albuterol Administration Is Commonly Associated With Increases in Serum Lactate in Patients With Asthma Treated for Acute Exacerbation of Asthma

Controversy exists around the incidence and cause of hyperlactatemia during asthma exacerbations. We evaluated the incidence, potential causes, and adverse events of hyperlactatemia in patients with acute asthma exacerbation. This study was a subanalysis of subjects receiving placebo from a prospective, randomized trial evaluating an IV b -adrenergic agonist in acute asthma exacerbation. Plasma albuterol, serum lactate, and bicarbonate concentrations were measured at baseline and 1.25 h, and dyspnea score and spirometry were measured at baseline and hourly for 3 h. All subjects had a therapeutic trial comprising 5 to 15 mg nebulized albuterol, 0.5 to 1 mg nebulized ipratropium, and at least 50 mg oral prednisone or its equivalent prior to initiation of the study. Following randomization, subjects were treated with continued albuterol and IV magnesium at the discretion of their treating physician. Subjects were followed to hospital admission or discharge with follow-up at 24 h and 1 week. One hundred seventy-fi ve subjects were enrolled in the parent trial, with 84 in the placebo group. Sixty-fi ve had complete data. Mean SD albuterol administration prior to baseline was 12.3 5.3 mg. Mean baseline lactate was 18.5 8.4 mg/dL vs 26.5 11.8 mg/dL at 1.25 h ( P , .001). Forty-fi ve subjects (69.2%) had hyperlactatemia. Mean baseline bicarbonate level was 22.6 2.9 mEq/L vs 21.9 4.0 mEq/L at 1.25 h ( P 5 .11). Plasma albuterol concentration correlated with lactate concentration ( b 5 0.45, P , .001) and maintained a significant association after adjusting for asthma severity ( b 5 0.41, P 5 .001). Hyperlactatemia did not increase the risk of hospitalization or relapse ( P 5 .26) or was associated with lower FEV 1 % predicted at 3 h ( P 5 .54). Plasma albuterol was significantly correlated with serum lactate concentration after adjusting for asthma severity. Hyperlactatemia was not associated with poorer pulmonary function as measured by 3-h FEV 1 % predicted or increased hospitalization or relapse at 1 week.