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Background: Clinical assessment of metabolic acidosis in calves with neonatal diarrhea can be difficult because increased blood concentrations of d-lactate and not acidemia per se are responsible for most of the clinical signs exhibited by these animals., Objectives: To describe the correlation between clinical and laboratory findings and d-lactate concentrations. Furthermore, the theoretical outcome of a simplified treatment protocol based on posture/ability to stand and degree of dehydration was evaluated., Animals: A total of 121 calves with diagnosis of neonatal diarrhea admitted to a veterinary teaching hospital during an 8-month study period., Methods: Prospective blinded cohort study. Physical examinations were carried out following a standardized protocol. Theoretical outcome of treatment was calculated., Results: Type and degree of metabolic acidosis were age dependent. The clinical parameters posture, behavior, and palpebral reflex were closely correlated to base excess (r = 0.74, 0.78, 0.68; P < .001) and d-lactate concentrations (r = 0.59, 0.59, 0.71; P < .001), respectively. Thus, determining the degree of loss of the palpebral reflex was identified as the best clinical tool for diagnosing increase in serum d-lactate concentrations. Theoretical outcome of treatment revealed that the tested dosages of sodium bicarbonate are more likely to overdose than to underdose calves with diarrhea and metabolic acidosis., Conclusions and Clinical Importance: The degree of metabolic acidosis in diarrheic calves can be predicted based on clinical findings. The assessed protocol provides a useful tool to determine bicarbonate requirements, but a revision is necessary for calves with ability to stand and marked metabolic acidosis., (Copyright © 2011 by the American College of Veterinary Internal Medicine.)

Transient hyperinsulinism (HI) occurs in infants born to diabetic mothers, in infants experiencing perinatal asphyxia and in infants with intrauterine growth retardation. The precise mechanism of transient HI in these different aetiologies is not fully understood. Lactic acidosis is commonly seen in neonates as a secondary phenomenon due to hypoxia, hypovolaemia, anaemia and infection. The combination of transient HI and lactic acidosis is rare. We present the clinical and biochemical features of five infants presenting with transient HI associated with hyperlactataemia in the absence of markers of perinatal stress. This combination lasted for 3-4 weeks with complete resolution except in one patient in whom the hyperinsulinism lasted until 6 months before resolution. The precise mechanism of this association is not clear but may be related either to immaturity of the pyruvate dehydrogenase complex or to the accumulation of abnormal intramitochondrial intermediary metabolites. Infants presenting with HI should have a free flowing blood sample drawn for the measurement of plasma lactate levels.

The effects of agents used in the treatment of metabolic acidosis could depend on the induced changes in intracellular pH (pHi). To determine the effect of sodium bicarbonate on hepatic pHi and function, this agent was infused into anesthetized rats with acute metabolic acidosis due to either diabetic ketoacidosis (DKA) or HCl infusion. Hepatic pHi was measured by 31P-magnetic resonance spectroscopy (MRS). A substantial increase in pHi occurred (from 7.13 +/- 0.08 to 7.32 +/- 0.08, P < .05) despite an increase in mixed venous PCO2. Isolated livers from normal rats or those with DKA were perfused at pH 6.8 and normal PCO2. With infusion of sodium bicarbonate, there was again an increase in pHi (delta pHi, + 0.27 +/- 0.06, P < .02) despite increases in both portal and hepatic venous PCO2. Lactate uptake was increased twofold to threefold (P < .001) by bicarbonate infusion in perfusions from both types of animals. Glucose output was increased twofold (P < .001) only in livers from normal animals.

We administered dichloroacetate, which prevents or reverses hyperlactatemia in animals and lowers plasma lactate levels in human beings, to 13 patients with lactic acidosis of various causes. All had hypotension, and their acidemia had resisted treatment with sodium bicarbonate. The metabolic effects of dichloroacetate were evaluated in 11 patients. In seven dichloroacetate significantly reduced the level of arterial blood lactate (P less than 0.005) from the base-line value and raised the levels of arterial blood bicarbonate (P less than 0.02) and arterial pH (P less than 0.005). In six of these seven, the acidemia resolved completely with therapy. In 10 of the 13 patients systolic blood pressure increased by 10 to 40 mm Hg, and 4 patients had a 21 per cent increase in cardiac output (P less than 0.02). Despite improvement in their lactic acidemia, all patients but one died of their underlying disease. No serious drug-related toxicity occurred. We conclude that dichloroacetate is a safe and effective adjunct in the treatment of patients with lactic acidosis, although the ultimate prognosis may depend on the underlying disease.

Of 3 alcoholic patients with severe lactic acidosis, one had shoshin beriberi; the second--a beer drinker--presented with convulsions associated with hyponatraemia and complicated by rhabdomyolysis and was not thiamine-deficient; the third patient had convulsions associated with Korsakoff's syndrome and was thiamine-deficient. In all three patients treatment with thiamine administered alone corrected the lactic acidosis within less than 4 hours. In patient 1, this result was obtained after symptomatic treatment of shock and lactic acidosis had failed and more than 24 hours before the haemodynamic disorders were corrected. In patient 2, who had no haemodynamic nor haematosis disorders, the lactic acidosis was corrected within 2 hours, i.e. more than 24 hours before neurological improvement developed. In patient 3, the lactic acidosis was also corrected within 2 hours. These results suggest that thiamine should figure among the treatments of lactic acidosis in alcoholic patients. Since thiamine alone is capable of correcting severe lactic acidosis, at least in some of these patients, it deserves to be tried in other types of lactic acidosis.

Despite the host of complications which may be associated with intravenous sodium bicarbonate infusion, the use of this agent is a frequent necessity in patients with metabolic acidosis. No satisfactory formula for calculating bicarbonate dose had previously been described, although such an approach might be expected to reduce the incidence of these complications. The authors have devised a simple formula for bedside calculation of bicarbonate requirement in metabolic acidosis, designed to elevate th pH to the region about 7.30, and report their experience with the use of this formula in 13 instances. In all but one, the post-infusion pH was between 7.25 and 7.37, with a mean of 7.30 +/- 0.04 and no instances of serious overtitration. It is concluded that the formula is useful as a pragmatic aid in the management of patients with metabolic acidosis.

The metabolic and systemic effects of dichloroacetate (DCA) in the treatment of hypoxic lactic acidosis were evaluated in the dog and compared with the infusion of equal quantities of volume and sodium. Hypoxic lactic acidosis was induced by ventilating dogs with an hypoxic gas mixture of 8% oxygen and 92% nitrogen, resulting in arterial PO2 of less than 30 mmHg, pH below 7.20, bicarbonate less than 15 mM, and lactate greater than 7 mM. After, the development of hypoxic lactic acidosis dogs were treated for 60 min with either DCA as sodium salt or NaCl at equal infusions of volume and sodium. Dogs treated with DCA showed a significant increase of arterial blood pH and bicarbonate, and steady levels of lactate, whereas NaCl resulted in further declines of blood pH and bicarbonate, and rising blood lactate levels. Overall lactate production decreased during therapy with either regimen, but hepatic lactate extraction increased significantly with DCA, while it remained unchanged with NaCl. Tissue lactate levels in liver and skeletal muscle decreased significantly with DCA treatment but were unchanged with NaCl. Additionally, an increase in muscle intracellular pH was observed only in DCA treated dogs. A possible mechanism for the observed actions of DCA might be related to a significant increase in oxygen delivery to tissues. Such an effect was found with DCA administration, but was not observed with NaCl therapy. In conclusion, DCA therapy in hypoxic lactic acidosis has beneficial systemic effects compared with therapy with NaCl. DCA administration is accompanied by increases of blood pH and bicarbonate, a decrease in lactate production, and enhanced liver lactate extraction, and a lowering of tissue lactate levels.

This study was designed to evaluate the effects of dopamine and dobutamine on hemodynamics and plasma catecholamine levels during experimental lactic acid acidosis in dogs. During the normal acid-base state (pH 7.4, PCO2 40 mm Hg), cardiac output and stroke volume were significantly increased and systemic vascular resistance was decreased by the infusion of dopamine or dobutamine 20 mcg/kg/min. Dobutamine produced identical changes in cardiac output, stroke volume, and systemic vascular resistance even during severe lactic acid acidosis (pH 7.0, PCO2 40 mm Hg). Dopamine, however, failed to increase cardiac output and stroke volume and to decrease systemic vascular resistance during lactic acidosis. The plasma norepinephrine level was elevated from 0.49 to 3.01 ng/ml during normal acid-based state and from 1.76 to 9.53 ng/ml during severe lactic acid acidosis by the infusion of dopamine. Dobutamine infusion did not affect the plasma norepinephrine level during normal acid-base state but reduced the level during lactic acid acidosis. The marked increase in plasma norepinephrine following dopamine infusion may explain both the decrease in cardiac output and the increase in systemic vascular resistance in response to dopamine infusion during severe lactic acid acidosis. These results indicate that dobutamine may be more useful than dopamine in improving cardiac output during severe acidosis.

Three patients are reported on, who at the time of admittance showed a decompensated metabolic acidosis, elevated concentrations of serum lactate and a reduced kidney funktion. All the patients had taken guanidine derivates (phenformine, buformine) because of diabetes mellitus. The serum biguanid concentrations, however, were elevated in only two cases. Therapy of the lactic acidosis has to be directed at the underlying disease. In biguanid incluced acidosis, haemodialysis with simultaneous administration of sodium bicarbonate is indicated.

An 85-year-old female diabetic was admitted in coma, having been on antidiabetic treatment with the biguanide derivative "Silubin retard", 600 mg/d, for one-and-a-half months. The anion deficiency was 57 mmol/l, pH 6.9, suggesting the diagnosis of lactic acidosis in the absence of other causes of metabolic acidosis. Blood lactic acid levels of more than 16.65 mmol/l (150 mg/100 ml) confirmed the diagnosis. Administration of 875 mmol sodium bicarbonate over 12 hours corrected the deficiency. On admission to hospital there had been slight pre-renal failure. Myocardial infarction developed as a result of tissue hypoxia but did not prove clinically important. On the second day there were signs of a compensated disseminated intravascular coagulopathy with upper gastro intestinal haemorrhage. The woman died suddenly 18 days later of pulmonary embolism.

Severe lactic acidosis is associated with poor prognosis. Usually, the patient is treated with massive amounts of intravenous sodium bicarbonate, which in itself carries many undesirable consequences such as fluid overload and hypernatremia. We have successfully used peritoneal dialysis with a bicarbonate-buffered dialysate in the management of severe acidosis. Bicarbonate-buffered peritoneal dialysis provided an unlimited supply of physiologic buffer over a prolonged period without causing hypervolemia or hypernatremia. Furthermore, significant amounts of lactate were removed by dialysis. We, therefore, recommend the use of bicarbonate-buffered peritoneal dialysis as an adjunct in the treatment of severe lactic acidosis.

A 24-year-old Hispanic patient underwent surgery for multicentric granulocytic sarcomas. 17 days after reduction of the tumors he developed severe acute lactic acidosis, which responded only to aggressive chemotherapy but in a surprisingly short lapse of time.

The presence of lactic acidosis in the cerebrospinal fluid of patients suffering brain injury as the result of trauma, subarachnoid hemorrhage, neoplasia, or ischemia has been well documented. The authors theorized that this acidosis becomes harmful in itself, and that treatment with an alkalinizing agent (tris(hydroxymethyl)aminomethane: tromethamine) capable of penetrating the blood-brain barrier would be efficacious. Fifteen pairs of mongrel cats were subjected to a 2.85-atmosphere fluid-percussion injury (LD80), and were supported by respirators for up to 72 hours prior to being placed in cages for an additional 4 days of observation. Experimental cats underwent continuous infusion of tromethamine (begun 10 minutes after injury); control animals were infused with an equal volume of lactated Ringer's solution. Twenty percent of the control group survived until sacrificed on Day 7 post-injury. Survival in the tromethamine group was 60% (p less than 0.05), and morbidity also appeared to be reduced in the treated cats. Intracranial pressure (ICP) in treated cats was 60% (p less than 0.05) of that in the control cats after respirator support for 3 days. Tromethamine infusion was associated with improved survival, decreased morbidity, and decreased ICP when compared with results in control animals. The literature with regard to central nervous system acidosis has been reviewed in an attempt to clarify and define this problem.

Lactic acidosis is characterized by metabolic acidosis due to accumulation of H+ ions from lactic acid with blood lactate of at least 5 mM. The standard treatment is intravenous NaHCO3, with resultant mortality in excess of 50%. Despite the high mortality, the metabolic and systemic effects of NaHCO3 used in the treatment of lactic acidosis have not been extensively studied. The present experiments in diabetic dogs were designed to address these questions. Dogs with phenformin-induced lactic acidosis (blood lactate above 5 mM, arterial pH below 7.20) were treated with equimolar amounts of either NaCl or NaHCO3 or received no therapy. Intravenous NaHCO3 resulted in a decline of cardiac output and intracellular pH (pHi) of liver and erythrocytes, whereas treatment with NaCl did not. With NaHCO3 but not with NaCl infusion gut lactate production increased almost stoichiometrically, with no change in arterial pH or bicarbonate but with a doubling of lactate. Bicarbonate also resulted in a decrease of hepatic portal vein blood flow. The mean survival time and percent mortality were similar in NaCl- vs. NAHCO3(-) treated animals. Although both groups lived longer than did animals receiving no therapy, the differences were not significant. Thus, treatment of experimental lactic acidosis with either NaCl or NaHCO3 or with no therapy results in no change of blood pH and bicarbonate and in a similar mortality. In terms of systemic effects, however, NaHCO3 results in significant decrements of liver and erythrocyte pHi, hepatic portal vein blood flow, and cardiac output and in significant increments of gut lactate production, whereas NaCl does not. The data suggest that the rationale for therapy of lactic acidosis with NaHCO3 should probably be reevaluated.

Severe lactic acidosis is often associated with poor prognosis. Recognition and correction of the underlying process is the major step in the treatment of this serious condition. Intravenous administration of sodium bicarbonate has been the mainstay in the treatment of lactic acidosis. Aggressive use of this therapeutic modality, however, can lead to serious complications and should therefore be considered with caution. Peritoneal dialysis and hemodialysis provide large amounts of alkali without causing the hypernatremia or hypervolemia commonly associated with bicarbonate infusion. Peritoneal dialysis with bicarbonate-based dialysate, in particular, appears to be an ideal means of delivering physiologic buffer. Administration of methylene blue was initially thought to increase lactate metabolism by altering the cellular oxidative state. Its subsequent clinical use, however, showed little efficacy. Sodium nitroprusside has been advocated for the treatment of some forms of lactic acidosis as a method of alleviating regional hypoperfusion. Insulin therapy has been found to be quite useful in the treatment of phenformin-associated lactic acidosis and is recommended in this setting. Since dichloroacetate activates pyruvate dehydrogenase and enhances lactate metabolism, it may be a useful adjunct in the treatment of lactic acidosis.

Lactic acidosis not associated with hypoxic states has a high morbidity and mortality. Treatment of this condition has been supportive and the etiology poorly understood. We report a case of recurrent lactic acidosis in a patient with renal and hepatic insufficiency with hypoglycemia which was repeatedly reversed by restoring the glucose concentration to normal. This case and several others in the literature suggest a mechanism for the development of type II B hyperlactatemia and new approaches for therapy.

This concluding article of a two-part discussion deals with clinical presentations and management of the basic types of lactic acidosis - with and without appaent hypoxia - and the various complicating conditions that may coexist with them. Although symptomatic treatment is essential, cure can be effected only by seeking and treating the underlying cause of the electrolyte derangement.

A patient presented with widespread small cell carcinoma, abnormalities on liver function tests, and rapidly progressive lactic acidosis. The acidosis was totally corrected following chemotherapy. Prompt treatment in tumor-associated lactic acidosis may significantly prolong survival.

An "in vitro" model of one type of lactic acidosis was produced in rat hemi-diaphragms with inhibitors of pyruvate oxidation. In order to obtain this inhibition in the absence of hypoxia, two actions were sought; inhibiting the mitochondrial pyruvate transporter and lowering the rate of pyruvate diffusion into these mitochondria. alpha-Cyano-3-hydroxy cinnamate (CNCM) was utilized because it is a specific inhibitor of the mitochondrial pyruvate transporter. Aminooxyacetate (AOA) was employed because it leads indirectly to inhibition of the entry of cytoplasmic reducing power into mitochondria. As a result of the addition of this latter compound, pyruvate levels fell and this should decrease the rate of pyruvate diffusion into the mitochondria. Glucose was the only substrate provided to this tissue and its entry into the cells was promoted by insulin. The oxidation of U-14C glucose to 14CO2 was significantly reduced in the presence of CNCM and AOA, presumably reflecting the inhibition of pyruvate oxidation. Under these conditions, lactate accumulated and pyruvate fell; however, there was a significant accumulation of lactate plus pyruvate during the incubation period. This "in vitro" lactic acidosis was markedly diminished when acetate was also present. These results are consistent with the hypothesis that provision of an alternate substrate to the TCA cycle for ATP synthesis could lead to a decreased rate of glycolysis and thereby to a decreased rate of lactic acid accumulation in this "in vitro" model of lactic acidosis.

A male child presented on the first day of life with metabolic acidosis with elevated blood lactate (15 mM), pyruvate (0.4 mM), and free fatty acid (1.3 mM) levels and a blood pH of 7.16. The severity of the acidosis was diminished by intravenous administration of glucose in large doses and by bicarbonate. On two occasions, when the acidosis was particularly severe, peritoneal dialysis using an acetate buffer was required. Restriction of the dietary intake of saturated fatty acids or treatment with nicotinic acid also appeared to diminish the severity of acidosis. No improvement was achieved by the administration of thiamine or biotin. Tissues taken at postmortem showed normal activity of gluconeogenic enzymes and pyruvate dehydrogenase. The activity of pyruvate dehydrogenase in tissue homogenates preincubated with ATP was reduced by 60-75% both in liver of the patient and of the controls because of the inactivation of the enzyme by pyruvate dehydrogenase kinase. Addition of Ca++ and Mg++ to the inactivated enzyme caused a prompt return of the activity to normal in controls but not in the patient. This defect, which was apparent in muscle and liver but not in brain, we attribute to a markedly reduced activity of pyruvate dehydrogenase phosphatase in the patient.

Lactic acid is generated as the end product of anaerobic metabolism of glucose and is disposed by gluconeogenesis or oxidation. Changes in the lactate pyruvate ratio are not necessarily indicative of tissue hypoxia. The plasma lactate concentration is the result of lactate production and lactate removal (hepatic and renal gluconeogenesis; oxidation by muscle, liver and kidney). Lactic acidosis is defined as a state of metabolic acidosis (arterial pH less than 7.3) due to an increase in the blood concentration of lactate (greater than 2 mEq/l). Lactic acidosis may occur with evidence of tissue hypoxemia (type A) or in its absence (type B). Lactic acidosis has been described in association with phenformin therapy, hereditary enzymatic defects, hematological malignancy, prolonged fasting, shock with or without septicemia and occasionally without any underlying disease ("idiopathic" lactic acidosis). The therapy of lactic acidosis consists of administration of sodium bicarbonate and restoration of adequate tissue perfusion; hemodialysis may be helpful to control sodium excess and possibly to remove phenformin. The effectiveness of methylene blue, glucose and insulin are not yet established.

Four patients with severe lactic acidosis associated with septic shock were treated with sodium dichloroacetate (DCA) (50 mg/kg body wt), an activator of pyruvate dehydrogenase. All patients were in a group with an expected mortality rate of 90-100%, based on previous studies. In one patient, treatment with DCA was associated with a decrease in blood lactate levels from 11.2 mM before treatment to 0.8 mM 16 h later. Markedly elevated blood pyruvate and alanine levels also decreased to normal. After treatment, the arterial blood pH rose to 7.53, and vasopressor agents were no longer needed to support blood pressure. Some degree of biochemical improvement was also noted in the other cases in whom the blood lactate levels before treatment were 15, 17, and 31 mM. However, all three patients eventually died of refractory acidosis.

The administration of dichloroacetate (DCA) in cases of biguanide-induced lactic acidosis (LA) improves pyruvate oxidation and therefore increases energy production from glucose. Preliminary results of treatment of LA in humans are reported. A continuous fall in pyruvate was observed in all 3 cases after administration of at least 20 g of DCA (4 g i.v. bolus, then continuously 12 g/h). In Case 1, in which no supplementary measures for controlling the acidosis were applied, the acidosis did not improve and the patient died. In Case 2, despite administration of tris-buffer and dialysis, pH-values could not be raised sufficiently. The production of hydrogen ions persisted and lactate continued to rise. This patient also died. Case 3 was admitted in the beginning stages of a phenformin-induced LA, and in this case therapy was successful. The decline in pyruvate was accompanied by a slow fall in lactate, and a further fall in pH was averted. The clinical condition of the patient improved markedly after i.v. administration of a total of 34 g of DCA.

Cerebral ischemic insult is one of the most clinically significant conditions leading to irreversible brain cell damage and death. Animal studies have suggested that lowered intracellular pH due to the severe brain lactic acidosis following ischemia interferes with normal cell structure and function and leads to brain cell necrosis. Therefore, efforts directed to decreasing brain lactate may be beneficial in preventing brain cell damage and death. The goal of our study was to evaluate the effectiveness of postinsult treatment with dichloroacetate (DCA) in controlling increases in brain lactate following partial global ischemia (PGI) in rats. PGI was induced by bilateral carotid artery occlusion and induced hypotension. Animals that received DCA immediately after a 30-minute ischemic insult (n = 5) or 15 minutes after the end of an ischemic insult (n = 5) had cortical lactate levels that were significantly lower (P less than .005) than lactate levels in untreated insulted animals and that were not significantly different than those previously obtained with preinsult DCA treatment in rats subjected to 30 minutes of PGI. Treatment of rats with DCA following PGI may be effective in reducing cortical lactate levels and hence may limit irreversible damage to brain cells following cerebral ischemia.

A patient with phenformin-associated lactic acidosis was treated with insulin and showed marked improvement coincident with the expected onset of action of the insulin administered. Relative insulin deficiency was demonstrated although several phenomena characteristic of phenformin-associated lactic acidosis obscured its reflection in the usual indices. From data presented and a review of the literature the following pathogenesis is proposed for the observed metabolic derangement. A background of relative insulin deficiency would permit enhanced pyruvate (and hence lactate) formation from protein sources. Insulin deficiency would also lead to inhibition of pyruvate dehydrogenase which slows pyruvate removal. Phenformin accumulation (cf impaired renal function) further reduces pyruvate removal by decreasing its conversion to glucose, but in addition alters the redox state. For the lactic acidosis which results, insulin administration may thus constitute specific therapy. Diabetes 24:28-35, January, 1975.

The metabolic effects of NaHCO3 therapy in hypoxic lactic acidosis were evaluated in the anesthetized dog. Hypoxic lactic acidosis was induced by ventilating the dogs with a hypoxic gas mixture of 8% O2/92%N2, resulting in arterial PO2 of less than 30 mmHg, pH below 7.20, bicarbonate less than 12 mM, and lactate more than 7 mM. In this situation lactate accumulates because of overproduction of lactate by gut and carcass in the presence of a diminished capacity of the liver to extract lactate. After the development of hypoxic lactic acidosis the dogs were treated for 60 min with either NaHCO3 or NaCl or had no therapy. Sixty minutes of either treatment resulted in further declines of blood pH and bicarbonate that were similar in all three groups. NaHCO3-treated animals, however, showed an increase in blood lactate that were significantly higher than those treated with NaCl or those that had no therapy. This could be explained by a significantly higher gut lactate production with NaHCO3 therapy than in the NaCl-treated group. Concomitantly NaHCO3-treated animals showed a decrement in liver and gut blood flow that did not occur with NaCl treatment. Only NaHCO3 therapy was associated with a further decrease of liver intracellular pH, which could be attributed to both an increase in the CO2 load to the liver and increased tissue lactate levels, which were not observed with NaCl or no therapy. Additionally, liver lactate extraction was not improved by administration of NaHCO3 or NaCl.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium dichloroacetate prevents and fights against the severe hyperlactatemia and lactic acidosis induced by phenformin, intense muscular work, hypoxia and by adrenalin perfusion. The beneficent effects of sodium dichloroacetate and insulin are additive.