Lactate, Blood

MANAGING LACTIC ACIDOSIS. When taking metformin, the patient is at risk for lactic acidosis. The nurse monitors die patient for symptoms of lactic acidosis, which include unexplained hyperventilation, myalgia, malaise, gastrointestinal symptoms, or unusual somnolence If the patient experiences these symptoms, the nurse should contact the primary care provider at once. Elevated blood lactate levels of greater than 5 mmol/L are associated with lactic acidosis and should be reported immediately. Once a patient s diabetes is stabilized on metformin therapy, the adverse GI reactions that often occur at the beginning of such therapy are unlikely to be related to the drug therapy. A later occurrence of GI symptoms is more likely to be related to lactic acidosis or other serious disease. 

Anselme, F., Collomp, K., Mercier, B., Ahmaidi, S., and Prefaut, C., Caffeine increases maximal anaerobic power and blood lactate concentration, European Journal of Applied Physiology, 65, 188, 1992. 

Wiles, J. D., Bird, S. R., Hopkins, J., and Riley, M., Effects of caffeinated coffee on running speed, respiratory factors, blood lactate, and perceived exertion during 1500-m treadmill running, British Journal of Sports Medicine, 26, 116, 1992. 

McNaughton, L., Two levels of caffeine ingestion on blood lactate and free fatty acid responses during incremental exercise, Research Quarterly, 58, 255, 1987. 

M10. Marecaux, G., Pinsky, M. R., Dupont, E., Kahn, R. J., and Vincent, J. L., Blood lactate levels are better prognostic indicators than TNF and IL-6 levels in patients with septic shock. Intensive Care Med. 22,404-408 (1996). 

Systemic Human >16 min Resp Cardio Metab 5 M 5 M 2 M 5 M (increased blood lactate during exercise) Bhambhani and Singh 1991... 

Human 2 x 30 min Cardio Metab 10 10 (increase in blood lactate Bhambhani et al. 1997... 

In a subsequent study Bhambhani et al. (1997) observed significant increases in blood lactate concentrations in male and female volunteers exposed to 10 ppm hydrogen sulfide, although there was not a significant change in the activities of muscle lactate dehydrogenase, citrate synthase, or cytochrome oxidase. 

Reliable measurements of L-lactate are of great interest in clinical chemistry, the dairy and vine industry, biotechnology, or sport medicine. In particular, blood lactate levels are indicative of various pathological states, including shock, respiratory insufficiencies, and heart and liver diseases. Silica sol-gel encapsulation of the lactate dehydrogenase and its cofactor was employed as a disposable sensor for L-lactate51. The sensor utilized the changes in absorbance or fluorescence from reduced cofactor nicotinamide adenine dinucleotide (NADH) upon exposure to L-lactate. 

Blood lactate concentrations may be used as another measure of tissue oxygenation and may show better correlation with outcome than 02 transport parameters in some patients. 

Lactic acidosis occurs rarely but is a fatal complication in 50% of cases. Lacfic acidosis is characterized by an increase in blood lactate levels (greater than 5 mmol/L), a decrease in blood pH, and electrolyte disturbances. Signs and symptoms of lacf ic acidosis include unexplained hypervenf ilaf ion, myalgia, malaise, and somnolence, which may advance to cardiovascular collapse (shock), acute CHF, acute Ml, and prerenal azotemia. 

Common (type-Ia/von Gierke), severe hypoglycemia, growth retardation, enlarged liver and kidney, hypoglycemia, elevated blood lactate, cholesterol, triglycerides, and uric acid... 

Blood lactate, pyruvate, ACAC, , glucose and redox ratio should be measured using the same sample for a reliable calculation of redox status. 

Table 1.4.6 Reference values for blood lactate, pyruvate, ACAC and according to age, fed state and fasting state. L P lactate-.pyruvate ratio...

Pitfalls associated with metabolic screening are numerous. They can result from proximal tubulopathy, causing a reduction in blood lactate and an increase in urinary lactate from diabetes mellitus, hampering entry of pyruvate into the citric acid cycle from tissue-specific involvement or partial deficiency, which may barely alter the redox status in plasma. When metabolic tests are negative, respiratory chain deficiency may be misdiagnosed. 

Blood Lactate Levels during Vigorous Exercise... 

Relationship between Fructose 1,6-Bisphosphatase and Blood Lactate Levels A congenital defect in the liver enzyme fructose 1,6-bisphosphatase results in abnormally high levels of lactate in the blood plasma. Explain. 

No rise in blood lactate during strenuous exercise... 

Lactic acid is the cause of one of many possible disorders in human acid-base metabolism. Lactic acidosis represents an accumulation of lactic acid in the blood and tissues. This condition gradually depletes the natural buffers in the body and there is a consequent lowering of pH. As described in the entry on Glycolysis, lactic acid is the end product til (hat pmcess. Lactic acid blood levels are determined by at least Tour factors. The rate of generation of lactic acid the rate of transport from tissues to plasma and from plasma to the liver (point of utilization of lactic acid) the rate uf utilization and excretion of lactic acid by the kidneys. Normally, all of these funclions are maintained in balance to give a normal blood lactate concentration of about I niFq/l. 

A 42-year-old man developed nausea and vomiting and felt suicidal. He had type 2 diabetes and was taking metformin (56). His blood lactate concentration was 8.9 mmol/1, bicarbonate 16 mmol/1, and pH 7.2. Severe hypotension required intensive care. The lactate concentration rose to 22 mmol/1 and the bicarbonate fell to 6.7 mmol/1 and the pH to 6.89. The metformin concentration was high at 191 mg/1. He survived, having been treated with intermittent hemodialysis. 

Five patients with metformin-associated severe lactic acidosis, seen between 1 September 1998 and 31 May 2001, have been reported (58). Two had attempted suicide. All had severe metabolic acidosis with a high anion gap and raised blood lactate concentrations. Four developed profound hypotension and three had acute respiratory failure. Three had normal preceding renal function. Three required conventional hemodialysis and two continuous renal replacement therapy. 

All patients admitted to a hospital during 6 months who had taken at least one dose of metformin were retrospectively evaluated for susceptibility factors for metformin-associated lactic acidosis (8). There were 263 hospitalizations in 204 patients. In 71 admissions there was at least one contraindication, such as renal or liver disease, renal dysfunction, congestive cardiac failure, metabolic acidosis, or an intravenous iodinated contrast medium given within 48 hours of metformin. In 29 (41%) metformin was continued despite the contraindication. The most frequent contraindication was a raised serum creatinine, but in only eight of the 32 admissions was metformin withdrawn. Of nine patients using metformin who died (not necessarily directly related to metformin), six had an absolute contraindication. In two patients who died and in one who survived, blood lactate was increased and this was temporally related to the use of metformin. 

Lactate is an important marker compound in many biomedical, food and beverage applications. Blood lactate is monitored in exercise control and sports medicine, and D-lactate is an indicator of bacterial activity in wine fermentation [59,60,63]. Lactate produced from anaerobic respiration of cattle muscle subsequent to slaughter has been investigated as an indicator of meat freshness [62],... 

M. Kyrolainen, H. Hakanson, B. Mattiasson and P. Vadgama, Minimal fouling enzyme electrode for continuous flow measurement of whole blood lactate, Biosens. Bioelectron., 11 (1997) 1073-1081. 

Reilly T, Woodbridge V. Effects of moderate dietary manipulation on swim performance and on blood lactate—swimming velocity curves. Int J Sports Med 1999 20 93-97. 

Figure 18 Dynamics of carbohydrate and lactate in the muscle and blood of horse-mackerel during cruise swimming. The fatigue point lies anywhere between 8 and 10 h after the start. The starting level is assumed to be 100% and the curves show the percentage increase or decrease. O, glycogen in white muscle A, glycogen in red muscle , lactate in white muscle V, lactate in red muscle O, glucose in blood , lactate in blood.

These hypoxia acclimation processes take days to weeks to settle down at new steady states. However, when complete, hypoxia acclimations are able to compensate for the 02 deficit of hypoxia better than acute adjustments. For example, after acclimation in lowlanders, the V02max is still affected by hypoxia, but to a lesser degree than previously. There is less energy deficit due to 02 lack and less postexercise blood lactate accumulation. 

Blood Lactate Levels during Vigorous Exercise The concentrations of lactate in blood plasma before, during, and after a 400 m sprint are shown in the graph. 

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