Higher Blood Lactate Research Articles

Outcomes of extracorporeal life support for low cardiac output syndrome after major cardiac surgery

Extracorporeal life support (ECLS) is a widely accepted modality for the treatment of postoperative low cardiac output syndrome (LCOS) after major cardiac surgery by providing temporary circulatory support for the stunned myocardium. We sought to identify the factors that affect outcomes of ECLS for postoperative LCOS. From 2005 to 2011, of a total of 9267 adult patients underwent major cardiac surgery, 93 patients (aged, 60.6±13.8 years; 47 women) underwent ECLS to treat postoperative LCOS. Thirty-nine (41.9%) patients were weaned off ECLS successfully, and 1 patient underwent heart transplantation. A final total of 23 patients (24.3%), including 1 heart transplantation recipient, survived until the endof the follow-up period (median, 611 days; range, 125-2247 days). On logistic regression analysis, old age (P = .001), a high blood lactate level before ECLS initiation (P<.001), cardiopulmonary bypass weaning failure after surgery (P<.001), and postoperative bleeding (P=.012) were independent factors associated with mortality. In contrast, administration of anticoagulant nafamostat mesilate (P=.040) was found to be associated with improved outcomes of ECLS. When the predictive value of pre-ECLS blood lactate level for mortality was assessed using the receiver operating characteristic curve, the greatest accuracy was obtained at the cutoff value of 7.9 mmol/L, with 63% sensitivity and 68% specificity. High lactate level before ECLS is an independent predictor of mortality after ECLS, necessitating earlier ECLS implementations before profound lactic acidosis develops. Moreover, nafamostat mesilate should be considered as alternative to heparin to reduce the risk of bleeding in these high-risk patients.

Prognostic Significance of Blood Lactate and Lactate Clearance in Trauma Patients

Lactate has been shown to be a prognostic biomarker in trauma. Although lactate clearance has already been proposed as an intermediate endpoint in randomized trials, its precise role in trauma patients remains to be determined. Blood lactate levels and lactate clearance (LC) were calculated at admission and 2 and 4 h later in trauma patients. The association of initial blood lactate level and lactate clearance with mortality was tested using receiver-operating characteristics curve, logistic regression using triage scores, Trauma Related Injury Severity Score as a reference standard, and reclassification method. The authors evaluated 586 trauma patients (mean age 38±16 yr, 84% blunt and 16% penetrating, mortality 13%). Blood lactate levels at admission were elevated in 327 (56%) patients. The lactate clearance should be calculated within the first 2 h after admission as LC0-2 h was correlated with LC0-4 h (R=0.55, P<0.001) but not with LC2-4 h (R=0.04, not significant). The lactate clearance provides additional predictive information to initial blood lactate levels and triage scores and the reference score. This additional information may be summarized using a categorical approach (i.e., less than or equal to -20 %/h) in contrast to initial blood lactate. The results were comparable in patients with high (5 mM/l or more) initial blood lactate. Early (0-2 h) lactate clearance is an important and independent prognostic variable that should probably be incorporated in future decision schemes for the resuscitation of trauma patients.

Determination of the Maximal Lactate Steady State in Obese Zucker Rats

This study aims to identify the maximum lactate steady state (MLSS) in obese rats in order to provide a more effective tool in the exercise training prescription for this important animal model. To make such determination, obese (Zucker, n=5) (390.0±18.8 g) and lean (Wistar, n=5) (227.3±26.2 g) rats were studied. After adaptation of animals to treadmill, the MLSS was determined by using 3 different velocities (10 m.min⁻¹, 12.5 m.min⁻¹ and 15 m.min⁻¹ for Zucker and 15 m.min⁻¹, 20 m.min⁻¹ and 25 m.min⁻¹ for Wistar). The MLSS was defined as the highest blood lactate concentration that increased up to 1 mmol.L⁻¹ during constant exercise. In obese rats, the MLSS was found in a velocity considerably lower than in lean controls (12.5 m.min⁻¹ and 20 m.min⁻¹), respectively (p<0.05). Therefore, the identification of MLSS in obese Zucker rats is an important tool for exercise prescription and evaluation in obese rat models.

Venous lactate levels can be used to identify patients with poor outcome following community-onset norovirus enteritis

Norovirus enteritis (NVE) can be fatal in frail patients. High blood lactate levels indicate hypoperfusion and predict mortality in many infectious diseases. The objective was to determine the frequency and association with mortality of elevated lactate levels in patients with community-onset NVE. A retrospective cohort study was performed. All hospitalized adult patients with community-onset NVE verified by polymerase chain reaction during the period August 2008 to June 2009 were included. Vital signs and venous lactate on arrival, co-morbid conditions, and time of death were registered. The outcome measure was 30-day all-cause mortality. Eighty-two patients with a median age of 77 y (interquartile range (IQR) 53-86 y) were included, of whom 47 (57%) were female and 49 (60%) had at least 1 major co-morbid condition. Lactate levels were above the upper limit of normal (ULN; 1.6 mmol/l) in 45 patients (55%). The overall 30-day mortality rate was 7% (6/82). Mortality was 18% (5/28) with lactate ≥ 2.4 mmol/l (> 50% above the ULN) on admission compared to 2% (1/54) with lactate < 2.4 mmol/l (p < 0.05). Patients who died had a higher median lactate level compared to survivors: 4.5 (IQR 2.7-7.9) mmol/l vs 1.7 (IQR 1.3-2.5) mmol/l, respectively (p < 0.01). The adjusted odds ratio for death within 30 days for a 1 mmol/l increase in lactate was 2.5 (95% confidence interval 1.003-6.3, p = 0.049). We observed a high proportion of patients with elevated lactate levels in community-onset NVE. Lactate elevation could predict mortality. Measurement of blood lactate may be a valuable tool in the clinical management of patients with a suspected norovirus infection.

Marcadores pronósticos de mortalidad en el postoperatorio de las cardiopatías congénitas

IntroductionOur aim is to identify risk factors for mortality after surgery for congenital heart disease in children, in order to establish indications for extracorporeal membrane oxygenation (ECMO). Patients and methodsOne hundred and eighty six children underwent cardiac surgery with extracorporeal circulation from April 2007 to June 2009. The following parameters were measured serially during their stay in Paediatric Intensive Care (PICU): Arterial and venous blood pH, pCO2, base excess, oxygen saturation, arterio-venous oxygen saturation difference, oxygen extraction ratio, ventilatory dead space and intrapulmonary shunting. ResultsHospital mortality was 13,4%. The following risk factors for mortality were identified: age, bypass time, inotropic score, lactate level upon arrival in PICU including its peak value and its rate of variation, mixed venous saturation, base excess, ventilatory dead space, oxygen extraction ratio, and intrapulmonary shunting. However, the strongest predictors of mortality were bypass time, lactate levels upon admission on PICU, and the peak lactate level. Multivariate analysis showed a lactate level of 6.3mmol/l and a high blood lactate for 24hours to be independent predictors of mortality. ConclusionsThe peak lactate level is a strong predictor of mortality. As such, it would be a useful indicator of the need for ECMO support.

Mutations of the Mitochondrial-tRNA Modifier MTO1 Cause Hypertrophic Cardiomyopathy and Lactic Acidosis

Dysfunction of mitochondrial respiration is an increasingly recognized cause of isolated hypertrophic cardiomyopathy. To gain insight into the genetic origin of this condition, we used next-generation exome sequencing to identify mutations in MTO1, which encodes mitochondrial translation optimization 1. Two affected siblings carried a maternal c.1858dup (p.Arg620Lysfs(∗)8) frameshift and a paternal c.1282G>A (p.Ala428Thr) missense mutation. A third unrelated individual was homozygous for the latter change. In both humans and yeast, MTO1 increases the accuracy and efficiency of mtDNA translation by catalyzing the 5-carboxymethylaminomethylation of the wobble uridine base in three mitochondrial tRNAs (mt-tRNAs). Accordingly, mutant muscle and fibroblasts showed variably combined reduction in mtDNA-dependent respiratory chain activities. Reduced respiration in mutant cells was corrected by expressing a wild-type MTO1 cDNA. Conversely, defective respiration of a yeast mto1Δ strain failed to be corrected by an Mto1(Pro622∗) variant, equivalent to human MTO1(Arg620Lysfs∗8), whereas incomplete correction was achieved by an Mto1(Ala431Thr) variant, corresponding to human MTO1(Ala428Thr). The respiratory yeast phenotype was dramatically worsened in stress conditions and in the presence of a paromomycin-resistant (P(R)) mitochondrial rRNA mutation. Lastly, in vivo mtDNA translation was impaired in the mutant yeast strains.

Mixed Acid-Base Disorders, Hydroelectrolyte Imbalance and Lactate Production in Hypercapnic Respiratory Failure: The Role of Noninvasive Ventilation

BackgroundHypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure.MethodsSixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO2 and PaCO2 and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV.ResultsNine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7%) mixed respiratory acidosis–metabolic alkalosis, 10/36 (27.8%) respiratory acidosis and 3/5 (60%) mixed respiratory-metabolic acidosis patients (p = 0.026), with durations of 45.1±9.8, 36.2±8.9 and 53.3±4.1 hours, respectively (p = 0.016). The duration of ventilation was associated with higher blood lactate (p<0.001), lower pH (p = 0.016), lower serum sodium (p = 0.014) and lower chloride (p = 0.038). Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis–metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder.ConclusionsMixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated.

Evaluation of Exertion and Capture Stress in Serum of Wild Dugongs (Dugong dugon)

Seven hundred fifty-one dugongs (Dugong dugon) were pursued, captured, and handled for up to 20 min for population sampling. Fifty of these dugongs were then removed from the water for up to 55 min for comprehensive medical examination. Fifty whole blood and separated serum samples were analyzed for potassium, sodium, chloride, creatinine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), urea, creatinine, glucose, anion gap, and total blood CO2. Serum biochemical variables of the dugong were compared with those obtained in previous studies of the related West Indian manatee, a mammal that does not appear to experience capture myopathy based on available data. Differences between these species included higher blood sodium and chloride in dugongs, which may reflect differences in salt balance and renal function, and higher blood lactate and CO2. Some biochemical analytes such as CK and AST, which may be indicative of rhabdomyolysis associated with capture stress myopathy (a potentially fatal condition for which dugongs have been thought to be highly susceptible) were high compared with levels previously measured in wild West Indian manatees (Trichechus latirostris). One of the 50 dugongs had marked elevations of CK and AST but showed no other clinical indications of rhabdomyolysis associated with capture myopathy such as hyperthermia. Rather, generally high levels of lactate, CK, and AST most probably reflect metabolic acidosis resulting from the exertion involved in the pursuit prior to capture. Earlier observations suggesting that dugongs were probably susceptible to capture stress myopathy (based on high serum potassium levels) were not supported by this study. Capture and handling methods currently used on dugongs in this research program do not appear to result in acute capture stress.

Lactate as a predictor of mortality in Malawian children with WHO-defined pneumonia

ObjectivesTo determine whether blood lactate measured at the time of presentation to hospital predicted outcome in children with pneumonia in Malawi, and to understand the factors associated with high blood...

Effect of creatine plus caffeine supplements on time to exhaustion during an incremental maximum exercise

This study investigated the effects of acute caffeine ingestion following short-term creatine supplementation on an incremental cycling to exhaustion task. Twelve active males performed the task under three conditions: baseline condition (BASE, no ergogenic aid), creatine plus caffeine condition (CRE + CAF), and creatine with placebo condition (CRE + PLA). Following the establishment of BASE condition, participants were administered CRE + CAF (0.3 g·kg−1·day−1 of creatine for 5 days followed by 6 mg·kg−1 of caffeine 1 h prior to testing) and CRE + PLA (0.3 g·kg−1·day−1 of creatine for 5 days followed by 6 mg·kg−1 of placebo 1 h prior to testing) in a double-blind, randomized crossover and counterbalancing protocol. No significant differences were observed in relative maximal oxygen consumption ([Vdot]O2max) (51.7±5.5, 52.8±4.9 and 51.3±5.6 ml·kg−1·min−1 for BASE, CRE + CAF and CRE + PLA, respectively; P>0.05) and absolute [Vdot]O2max (3.6±0.4, 3.7±0.4 and 3.5±0.5 l·min−1 for BASE, CRE + CAF and CRE + PLA, respectively; P>0.05). Blood samples indicated significantly higher blood lactate and glucose concentrations in the CRE + CAF among those in the BASE or CRE + PLA condition during the test (P<0.05). The time to exhaustion on a cycling ergometer was significantly longer for CRE + CAF (1087.2±123.9 s) compared with BASE (1009.2±86.0 s) or CRE + PLA (1040.3±96.1 s). This study indicated that a single dose of caffeine following short-term creatine supplementation did not hinder the creatine–caffeine interaction. In fact, it lengthened the time to exhaustion during an incremental maximum exercise test. However, this regime might lead to the accumulation of lactate in the blood.

Physiological Stress of Competing and Training in Figure Skating

Physiological Stress of Competing and Training in Figure Skating Esa Hynynen1, Ville Vesterinen1, Tommi Sipari1, Laura Tast2, Ari Nummela1 1 KIHU – Research Institute for Olympic Sports, Jyvaskyla, Finland 2 Finnish Figure Skating Association, Helsinki, Finland Despite the merits of many studies on biomechanics and injuries in figure skating, physiological demands of figure skating remain unclear. PURPOSE: This study was made to investigate the physiological stress of training and competing in figure skaters. METHODS: Five men and five women of the national team of Finland participated in this study. Heart rate was recorded during the short program and free skating competition. Fingertip blood samples were collected immediately after the program sessions to analyze blood lactate concentrations. The athletes also rated their perceived exertion (0-10) after program sessions. In addition, the same measurements were done in two training sessions (technique and program) in two men and two women. RESULTS: Figure skaters had higher blood lactate concentration after free skating when compared to the short program (12.0 ± 2.2 mM vs. 10.7 ± 2.2 mM, P < 0.05, respectively). They also rated their perceived exertion higher after free skating when compared to the short program (8.2 ± 1.1 vs. 6.4 ± 1.4, P < 0.01). No differences were found in the heart rate responses to competitions between the short program and free skating. Blood lactate concentrations were higher in competitions when compared to the technique training sessions (1.3 ± 2.2 mM, P < 0.01) and program training sessions (7.1 ± 2.6 mM, P < 0.05). The perceived exertion in technique training session was rated lower (5.0 ± 1.6) than in the competitions (P < 0.05) and in program training sessions (6.5 ± 1.7, P < 0.05). Also the average heart rate was higher during the competition (188 ± 7 bpm) than in technique training sessions (132 ± 20 bpm, P < 0.05) and program training sessions (175 ± 8 bpm, P < 0.05). CONCLUSION: The present findings of high heart rate and blood lactate concentrations suggest that the physiological stress is high during the competitions and during the program training. The longer duration of the free skating may explain the higher blood lactate concentrations and perceived exertion in comparison to the short program. The competition situation seems to accentuate the sympathetic activity as suggested by higher heart rate during program in competition than in training.

Continuing high early death rate in acute promyelocytic leukemia: a population-based report from the Swedish Adult Acute Leukemia Registry

Our knowledge about acute promyelocytic leukemia (APL) patients is mainly based on data from clinical trials, whereas population-based information is scarce. We studied APL patients diagnosed between 1997 and 2006 in the population-based Swedish Adult Acute Leukemia Registry. Of a total of 3897 acute leukemia cases, 3205 (82%) had non-APL acute myeloid leukemia (AML) and 105 (2.7%) had APL. The incidence of APL was 0.145 per 100,000 inhabitants per year. The median age at the time of diagnosis was 54 years; 62% were female and 38% male. Among younger APL patients, female sex predominated (89% of patients <40 years). Of the 105 APL patients, 30 (29%) died within 30 days (that is, early death (ED)) (median 4 days) and 28 (26%) within 14 days from diagnosis. In all, 41% of the EDs were due to hemorrhage; 35% of ED patients never received all-trans-retinoic acid treatment. ED rates increased with age but more clearly with poor performance status. ED was also associated with high white blood cells, lactate dehydrogenase, creatinine, C-reactive protein and low platelet count. Of non-ED patients, 97% achieved complete remission of which 16% subsequently relapsed. In total, 62% are still alive at 6.4 years median follow-up. We conclude that ED rates remain very high in an unselected APL population.

Spinal cord excitability is not influenced by elevated blood lactate levels

The aim of the present study was to examine the association of high blood lactate levels, induced with a maximal cycling or with an intravenous infusion, with spinal cord excitability. The study was carried out on 17 male athletes; all the subjects performed a maximal cycling test on a mechanically braked cycloergometer, while 6 of them were submitted to the intravenous infusion of a lactate solution (3 mg/kg in 1 min). Before the exercise or the injection, also at the end as well as 5 and 10 min after the conclusion, venous blood lactate was measured and excitability of the spinal α-motoneurons was evaluated by using the H reflex technique. In both experimental conditions, it has been observed that an exhaustive exercise is associated with a strong increase of blood lactate (but not of blood glucose) and with a significant reduction of spinal excitability. Since a similar augment of blood lactate induced by an intravenous infusion, in subjects not performing any exercise, is not associated with significant changes of spinal excitability, it can be concluded that the increase of blood lactate levels during a maximal exercise is not per se capable of modifying the excitability of spinal α-motoneurons.

Gender differences in changes of motor cortex excitability during elevated blood lactate levels

Gender differences in cortical excitability have been detected by using transcranial magnetic stimulation (TMS). The present study was carried out to compare the effects of high blood lactate levels, induced by performing a maximal exhausting exercise, on the excitability of the primary motor cortex in young male and female athletes. The study was carried out on 21 young males and 20 females from the Middle Distance Track Team of our university. Before the exercise, at the end, as well as 5 and 10 min after the conclusion, venous blood lactate and glucose were measured and excitability of the motor cortex was evaluated by using TMS. We observed a similar enhancement of excitability of primary motor cortex, concomitantly with an increase of blood lactate, in both young male and female athletes. However, the improvement was significantly higher (p < 0.05) in women (37.4% ± 3.97) than in men (42.0% ± 6.43), suggesting a greater sensitiveness of female cerebral cortex to blood lactate.

Heart Rate, Oxygwn Consumption and Blood Lactate Responses During Specific Training in Amateur Boxing

The study was undertaken with a view to investigate the physiological responses of amateur boxers during specific activity in the boxing arena, with special reference to their physiological evaluation in the laboratory. The study was carried out on 6 elite Indian National boxers in 3 phases. In phase 1, the VO2max of the boxers was evaluated in the laboratory following a graded running protocol on a treadmill. In Phase 2, the boxers were evaluated in the boxing arena, during simulated boxing on a punching bag for 4 rounds of 2 min duration with 1 min rest pauses in between. The movements were kept similar to actual boxing and the punching frequencies were kept fast and individualized. The physiological variables were recorded on a COSMED K4 RQ portable telemetric gas analyzer (Cosmed, Italy). In Phase 3, heart rate and blood lactate responses of the boxers were observed during sparring for 2X6 rounds in the boxing ring, for 3 times during the training phase, to observe the lactate tolerance capacity. After the end of activi ty in each phase, a blood sample was collected from the fingertip for estimation of whole blood lactate on an YSI portable 1500 sport model lactate analyzer (YSI, USA). The mean VO2max of the boxers was 59.5 ± 4.7 ml/kg/min on the treadmill. The mean peaks VO2 of the boxers in 2X4 simulated rounds were 56.1, 57.5, 57.7 and 59.3 ml/kg/min, respectively. The mean heart rate and blood lactate were 192 bpm and 13.6 mMol/L, and were observed to be higher than most of the intermittent team events. The present study highlighted that the amateur boxers participating in 2X4 rounds, should be able to tolerate a high blood lactate concentration (14-15 mMol/L) and a high heart rate (190-200 b/min) over a total duration of one bout (11 min). The on court training in amateur boxing imparted high demands on cardiorespiratory and metabolic variables. 1)

Aerobic capacity of rats recovered from fetal malnutrition with a fructose-rich diet

The objective of this study was to analyze the aerobic capacity, through the maximal lactate steady-state (MLSS) protocol, of rats subjected to fetal protein malnutrition and recovered with a fructose-rich diet. Pregnant adult Wistar rats that were fed a balanced (17% protein) diet or a low-protein (6% protein) diet were used. After birth, the offspring were distributed into groups according to diet until 60 days of age: balanced (B), balanced diet during the whole experimental period; balanced-fructose (BF), balanced diet until birth and fructose-rich diet (60% fructose) until 60 days; low protein-balanced (LB), low-protein diet until birth and balanced diet until 60 days; and low protein-fructose (LF), low protein diet until birth and fructose-rich diet until 60 days. It was verified that the fructose-rich diet reduced body growth, mainly in the BF group. There was no difference among the groups in the load corresponding to the MLSS (B, 7.5+/-0.5%; BF, 7.4+/-0.6%; LB, 7.7+/-0.4%; and LF, 7.7+/-0.6% relative to body weight). However, the BF group presented higher blood lactate concentrations (4.8+/-0.9 mmol.L(-1)) at 25 min in the load corresponding to the MLSS (B, 3.2+/-0.9 mmol.L(-1); LB, 3.4+/-0.9 mmol.L(-1); and LF, 3.2+/-1.0 mmol.L(-1)). Taken together, these results indicate that the ability of young rats to perform exercise was not altered by intrauterine malnutrition or a fructose-rich diet, although the high fructose intake after the balanced diet in utero increased blood lactate during swimming exercises in rats.

Elevated lactate in ethylene glycol poisoning: True or false?

Abstract Background There have been an increasing number of reports on false increase of lactate in ethylene glycol poisoning. We recently encountered two cases of ethylene glycol poisoning with very high blood lactate concentrations on ABL blood gas analyzers. Methods Patient plasma lactate concentrations were measured on different chemistry instruments in addition to ABL analyzer. Serum ethylene glycol and glycolic acid were also determined. Lactate values were determined from samples spiked with various amounts of glycolic acid. Results In case 1, all the chemistry instruments produced similar lactate results compared to that by ABL analyzer whereas in case 2, the lactate on the ABL was dramatically elevated compared to that from all the chemistry analyzers. There was no glycolic acid detected in case 1 but high glycolic acid was obtained in case 2. Increased concentrations of glycolic acid resulted in a significant positive interference on lactate measurements on the ABL analyzer but none on other instruments. Conclusions False increase of blood lactate by blood gas analyzers may occur but true increase of lactate can also be observed in ethylene glycol poisoning. Elevated lactate concentrations on blood gas analyzers should be confirmed by a chemistry analyzer in the differential diagnosis of ethylene glycol poisoning.

Effects of anesthesia and surgery on serial blood gas values and lactate concentrations in yellow perch (Perca flavescens), walleye pike (Sander vitreus), and koi (Cyprinus carpio)

OBJECTIVE-To evaluate serial blood gas values and lactate concentrations in 3 fish species undergoing surgery and to compare blood lactate concentrations between fish that survived and those that died during the short-term postoperative period. DESIGN-Prospective cohort study. Animals-10 yellow perch, 5 walleye pike, and 8 koi. PROCEDURES-Blood samples were collected from each fish at 3 time points: before anesthesia, during anesthesia, and immediately after surgery. Blood gas values and blood lactate concentrations were measured. Fish were monitored for 2 weeks postoperatively. RESULTS-All walleye and koi survived, but 2 perch died. Blood pH significantly decreased in perch from before to during anesthesia, but increased back to preanesthesia baseline values after surgery. Blood Pco(2) decreased significantly in perch from before anesthesia to immediately after surgery, and also from during anesthesia to immediately after surgery, whereas blood Pco(2) decreased significantly in koi from before to during anesthesia. Blood Po(2) increased significantly in both perch and koi from before to during anesthesia, and also in koi from before anesthesia to immediately after surgery. For all 3 species, blood lactate concentrations increased significantly from before anesthesia to immediately after surgery. Blood lactate concentration (mean +/- SD) immediately after surgery for the 8 surviving perch was 6.06 +/- 1.47 mmol/L, which was significantly lower than blood lactate concentrations in the 2 nonsurviving perch (10.58 and 10.72 mmol/L). CONCLUSIONS AND CLINICAL RELEVANCE-High blood lactate concentrations following surgery in fish may be predictive of a poor short-term postoperative survival rate.

A Brief Description of the Biomechanics and Physiology of a Strongman Event: The Tire Flip

The purpose of this study was to (a) characterize the temporal aspects of a popular strongman event, the tire flip; (b) gain some insight into the temporal factors that could distinguish the slowest and fastest flips; and (c) obtain preliminary data on the physiological stress of this exercise. Five resistance-trained subjects with experience in performing the tire flip gave informed consent to participate in this study. Each subject performed 2 sets of 6 tire flips with a 232-kg tire with 3 minutes of rest between sets. Temporal variables were obtained from video cameras positioned 10 m from the tire, perpendicular to the intended direction of the tire flip. Using the "stopwatch" function in Silicon Coach, the duration of each tire flip and that of the first pull, second pull, transition, and push phases were recorded. Physiological stress was estimated via heart rate and finger-prick blood lactate response. Independent T-tests revealed that the 2 faster subjects (0.38 +/- 0.17 s) had significantly (p < 0.001) shorter second pull durations than the 3 slower subjects (1.49 +/- 0.92 s). Paired T-tests revealed that the duration of the second pull for each subject's fastest 3 trials (0.55 +/- 0.35 s) were significantly (p = 0.007) less than their 3 slowest trials (1.69 +/- 1.35 s). Relatively high heart rate (179 +/- 8 bpm) and blood lactate (10.4 +/- 1.3 mmol/L(-1)) values were found at the conclusion of the second set. Overall, the results of this study suggest that the duration of the second pull is a key determinant of tire flip performance and that this exercise provides relatively high degrees of physiological stress.

Vertical Jump Performance and Blood Ammonia and Lactate Levels During Typical Training Sessions In Elite 400-m Runners

This study described the effects of 6 typical high-intensity intermittent running training sessions of varying distances (60-300 m) and intensities (80-105% of the individual best 400-m record time) on blood ammonia and lactate concentration changes and on vertical jumping height, in twelve 400-m elite male runners. At the end of the training sessions, similar patterns of extremely high blood lactate (14-23 mmol.L) and ammonia levels (50-100 mumol.L) were observed. Vertical jumping performance was maintained during the initial exercise bouts up to a break zone of further increase in the number of exercise bouts, which was associated, especially in subjects with the highest initial vertical jump, with a pronounced decrease (6-28%) in vertical jumping performance, as well as with blood lactate concentrations exceeding 8-12 mmol.L, and blood ammonia levels increasing abruptly from rest values. This break zone may be related to signs of energetic deficiency of the muscle contractile machinery associated with the ability to regenerate adenosine triphosphate at high rates. It is suggested that replacing some of these extremely demanding training sessions with other intermittent training sessions that preserve muscle generating capacity should allow elite athletes to practice more frequently at competitive intensity with lower fatigue.