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Severe perioperative lactic acidosis: how clinically significant is it?

BACKGROUND: Lactic acidosis, generally defined as a plasma lactate concentration in excess of 5 mmol/L with a concomitant blood pH less than 7.25, is reported to have a direct association with mortality. OBJECTIVE: To report a case of unexplained perioperative lactic acidosis and to discuss the etiology, recognition, treatment, and importance of a transient rise in plasma lactate concentration. SUMMARY: Severe lactic acidosis developed in a 40-year-old man with Crohn's disease during major abdominal surgery. The plasma lactate concentration reached 16.9 mmol/L (normal range 1.5 to 2.2 mmol/L). This condition resolved within 14 hours without harm to the patient. CONCLUSIONS: When lactate accumulates in the perioperative period, the responsible condition is most often self-limiting. Reversible, subacute, marked lactic acidosis should not be assumed to predict mortality as it does in patients whose plasma lactate concentrations remain chronically elevated during severe systemic diseases such as sepsis.

Acidosis, Lactic↗

An unusual cause of severe metabolic acidosis.

A 50-year-old man was transferred to the intensive care unit with high anion gap metabolic acidosis. Investigations suggested a diagnosis of pyroglutamic acidaemia. Factors contributing to the acidosis were medications (paracetamol and flucloxacillin), sepsis and renal failure. The acidosis resolved with supportive therapy and withdrawal of the drugs. It is important to recognise this treatable aetiology of metabolic acidosis.

Acetaminophen↗

Phenformin and hyperamylasemia in lactic acidosis.

All cases of lactic acidosis occurring during a 23-month period in a metropolitan teaching hospital were reviewed to ascertain the frequency of hyperamylasemia. Serum amylase activity had been measured in 12 of 26 patients and was elevated in eight (67%). Hyperamylasemia was not significantly more frequent in patients with phenformin-associated lactic acidosis than in patients with lactic acidosis who had not received phenformin. Serum amylase activity did not correlate with the severity of acidosis (arterial pH) or with renal function (serum creatinine).

Acidosis↗

Lactate homeostasis and lactic acidosis.

The roles of changes in cellular redox, interorgan lactate flux and balance, and quantitative aspects of lactate metabolism in the pathogenesis of lactic acidosis are discussed. Altered metabolism of pyruvate is central to the development of lactic acidosis and hyperlactatemia. Lactic acidosis occurs as a result of a relative or absolute imbalance in lactate production and utilization. Lactate utilization for oxidative purposes and for the resynthesis of glucose is essential for the maintenance of acid-base balance. Because of its role in lactate homeostasis the liver may play a central role in acid-base balance. Impairment of hepatic utilization of lactate may produce lactic acidosis.

Acidosis↗

Impact of peritoneal dialysis modality and acidosis on nutritional status in peritoneal dialysis patients.

Continuous ambulatory (CAPD) and continuous cyclic peritoneal dialysis (CCPD) differ in solute transport, and variances in mass balance could impact nutritional parameters. Chronic acidosis may decrease albumin synthesis and increase catabolism. We prospectively studied 50 peritoneal dialysis patients (age: 55 +/- 16 yrs; CAPD = 33; CCPD = 17) over 24 months. Acidosis was defined by an anion gap > 18 mEq/L. Bioimpedance analysis was used to estimate body cell mass and fat-free mass. Patients on CAPD had a lower body mass index than CCPD patients (27 +/- 5 kg/m2 vs. 29 +/- 9 kg/m2 respectively; P = 0.039). However no differences were observed in body cell mass (25 +/- 8 kg vs. 26 +/- 9 kg respectively; P = 0.787) or fat-free mass (53 +/- 14 kg vs. 50 +/- 18 kg respectively; P = 0.404). Urea kinetic modeling showed no differences in Kpt/V or nPCR (0.26 +/- 0.06 vs. 0.24 +/- 0.07; P = 0.709 and 0.67 +/- 0.29 g/kg per day vs. 0.65 +/- 0.23 g/kg per day; P = 0.709 for CAPD and CCPD respectively). When categorized by the presence of acidosis no differences were observed in body cell mass (24 +/- 8 kg vs. 27 +/- 9 kg respectively; P = 0.131) or fat-free mass (54 +/- 15 kg vs. 50 +/- 16 kg respectively; P = 0.348), while body mass index was greater in acidotic than nonacidotic individuals (30 +/- 8 kg/m2 vs. 26 +/- 6 kg/m2 respectively; P = 0.005). Dietary protein intake assessed as nPCR was similar in both groups (0.64 +/- 0.26 vs. 0.71 +/- 0.28 g/kg per day; P = 0.319, for CAPD and CCPD respectively). We conclude that over a 24-month period neither peritoneal dialysis modality nor the presence of acidosis has a detrimental influence on nutritional parameters in well dialyzed patients.

Acidosis↗

[Metformin associated lactic acidosis--case reports and literature review].

BACKGROUND: The use of metformin in the treatment of diabetes mellitus type II is increasing. The drug has several advantageous metabolic effects, and is considered safe if not used in the presence of contraindications, in particular renal failure. MATERIAL AND METHODS: We present a patient with metformin associated lactic acidosis, to remind of a potentially lethal adverse reaction. We also review the literature about incidence and risk, prognosis and treatment of the disease. RESULTS: Our patient was a 72 year old woman with diabetes mellitus type II treated with metformin, who presented with acute renal failure, severe metabolic acidosis and circulatory failure. Treatment with bicarbonate buffer and vasopressors did not improve her condition, only after hemodialysis was her situation stabilised. INTERPRETATION: Metformin associated lactic acidosis must be considered in obscure metabolic acidosis in diabetic patients. The single most important therapeutic approach appears to be immediate hemodialysis.

Acidosis, Lactic↗

[Electrolyte abnormalities and metabolic acidosis in two Duchenne muscular dystrophy patients with advanced congestive heart failure].

We experienced two Duchenne muscular dystrophy patients with advanced congestive heart failure, who showed abrupt severe hyponatremia, hyperkalemia and metabolic acidosis. Two patients received respiratory management, parenteral nutrition, and drugs including angiotensin converting enzyme inhibitors (ACEI). The patient 1 who was 19 years old showed abdominal pain, hematuria, diarrhea and disorientation. Laboratory findings were as follows; Na 120 mEq/L, K 7.3 mEq/L, BUN > 140 mg/dl (scale over), ACTH 20.2 pg/ml, cortisol 25 micrograms/dl, renin 40.7 ng/ml/hr and aldosterone 203 ng/dl. Arterial blood gas analysis (ABG) showed metabolic acidosis (pH 7.232). Combination therapy with hydrocortisone, glucose-insulin therapy (GIT) and NaHCO3 successfully rescued this patient. The patient 2 (28 years of age) was admitted to our hospital because of congestive heart failure. Laboratory findings were as follows; Na 129 mEq/L, K 5.5 mEq/L, BUN 60 mg/dl, cortisol 21 micrograms/dl, renin 36 ng/ml/hr and aldosterone 47 ng/dl. He complained abdominal discomforts from the next day of admission. Ten days after the admission Na, K and BUN were 111 mEq/L, 6.2 mEq/L and 154 mg/dl, respectively. ABG showed compensated metabolic acidosis. He fell into shock during GIT therapy. Laboratory findings at that time were as follows; Na 108 mEq/L, K 3.2 mEq/L, ACTH 77.6 pg/ml, cortisol 24 micrograms/dl, renin 58 ng/ml/hr and aldosterone 24 ng/dl. Although hydrocortisone was introduced, he could not recover and died. There are some reports about life-threatening electrolyte abnormalities and metabolic acidosis in the patients receiving ACEI. These phenomena were more frequent in patients with renal dysfunction and/or congestive heart failure. Hyponatremia, hypovolemia, combination therapy with nonsteroidal anti-inflammatory drugs (NSAID) and/or potassium sparing diuretics were reported as risk factors. We could not prove the correlation between the acute changes in our cases and ACEI. However ACEI is suspicious, because many of these risk factors were observed in our cases. Aldosterone was extremely elevated in the patient 1 when potassium was severely elevated. On the other hand, the patient 2 showed lower aldosterone level after correction of potassium than that on admission. Potassium is regarded as a major secretion factor of aldosterone for patients receiving ACEI. The fact the patient 2 fell into shock during GIT, tells us that we should use steroid simultaneously when we try to correct potassium quickly in severe cases, because acute reduction of potassium may decrease aldosterone. Today, ACEI is a common drug for CHF, so we should pay attentions that ACEI could cause such acute changes. To prevent such acute changes, excessive restriction of water and sodium intake should be avoided. If possible, NSAID and potassium sparing diuretics also should be avoided. Steroid therapy must be introduced rapidly when needed.

Acidosis↗

Catabolism in uremia: the impact of metabolic acidosis.

Chronic metabolic acidosis stimulates the catabolism of bone and muscle in experimental animals and humans. The toxicity caused by acidosis involves changes in endocrine function and toxicity arising from the homeostatic responses that are activated by the body to maintain pH near normal levels. Glucocorticoids, insulin, insulin-like growth factor-1, and parathyroid hormone play important roles in the homeostatic responses of bone and muscle to acid. Bone buffering of acid and the resulting increase in renal calcium excretion leads to negative calcium balance. Activation of the ubiquitin-proteasome proteolytic system and branched-chain ketoacid dehydrogenase in muscle, along with hepatic glutamine synthesis in the liver and renal glutamine uptake, are homeostatic mechanisms that cause negative nitrogen balance and loss of muscle mass. Treating the acidosis of chronic renal insufficiency improves both bone and muscle metabolism by reducing the loss of calcium and protein and amino acids in the two organs, respectively. Thus, treating acidosis suppresses both bone and muscle catabolism in patients with normal and reduced renal function.

Acidosis↗

Life threatening hyperkalemia and acidosis secondary to trimethoprim-sulfamethoxazole treatment.

We present a 77-year-old male with moderate chronic renal insufficiency from diabetic nephropathy who developed severe metabolic acidosis and life threatening hyperkalemia on treatment with regular dose of trimethoprim-sulfamethoxazole (TMP-SMZ) for urinary tract infection. The metabolic acidosis and hyperkalemia resolved upon appropriate medical intervention and discontinuation of TMP-SMZ. While hyperkalemia has commonly been reported with high dose of TMP-SMZ, severe metabolic acidosis is quite uncommon with regular dose TMP-SMZ. We emphasize that patients with renal tubular acidosis (RTA), renal insufficiency, aldosterone deficiency, old age with reduced renal mass and function, and angiotensin converting enzyme (ACE)-inhibitor therapy are at high risk of developing these severe and potentially life threatening complications.

Acidosis, Renal Tubular↗

[The intensity of metabolic acidosis and serum lactate concentrations in relation to illness severity evaluated by SNAP in newborns admitted to intensive care unit].

Some authors questioned the prognostic value of indicators of metabolic acidosis (pH, HCO3, BE). On the other hand, the elevated serum lactates are considered to be sensitive markers of anaerobic metabolism in peripheral tissues with significant predictive value. The aim of the study was to analyse the relationship between SNAP index and serum lactates as well as the markers of metabolic acidosis in newborns treated in intensive care unit (ICU). 173 newborns up to the 72 hour of life admitted to the ICU were enrolled into the study. Mean birth weight was 2045 +/- 808 grams, mean gestational age--35 +/- 4 weeks. SNAP (evaluated on the first day of hospitalization) ranged from 0 to 41 points, with the mean value of 9 points. Based on the SNAP, the study group was divided into four subgroups: 0-8 points, 9-16 points, 17-24 points and more than 24 points. Observations were prolonged up to the 48 hour of hospital stay, with at least one measurement of serum lactates, blood gases and calculation of the anion gap. Elevated serum lactates were found even with the SNAP as low as 8 points, but significantly high concentration of lactates was observed in newborns with more than 24 points. Uncompensated metabolic acidosis was found in newborns with more than 9 points in SNAP. Any relationship was found between the SNAP at admission and HCO3 concentration or anion gap. Serum lactates correlated much better with the clinical status of the newborn in comparison to markers of metabolic acidosis (pH, HCO3, BE).

Acidosis, Lactic↗

Effect of NH4Cl acidosis on the function of renin-angiotensin-aldosterone system in newborn infants.

The present study was undertaken to assess the influence of acute metabolic acidosis on the activity of renin-angiotensin-aldosterone system and renal function in a group of seven one-week-old neonates with mean birth weight of 2164 g (range: 1300-3750 g) and mean gestational age of 34 weeks (range: 28-40 weeks) undergoing oral NH4Cl load. NH4Cl was given in a dose of 2.8 mEq/kg to evaluate renal acidification. Prior to and following NH4Cl administration blood acid-base parameters, plasma urinary electrolytes, creatinine and aldosterone concentration as well as plasma renin activity, glomerular filtration rate, urine flow rate and net acid secretion were measured. NH4Cl administration significantly depressed blood pH (P < 0.05), total CO2 content (P < 0.01) and base excess (P < 0.01) and resulted in a significant elevation of plasma potassium concentration (P < 0.05). Furthermore, NH4Cl ingestion significantly increased urine flow rate, sodium, chloride and net acid excretion. In response to NH4Cl acidosis no consistent change in plasma renin activity and plasma aldosterone concentration could be detected. There was, however, an about 50% increase in urinary aldosterone excretion from the control value of 4.1 +/- 1.2 micrograms/day to 6.8 +/- 2.3 micrograms/day (P < 0.05) after NH4Cl administration. These data suggest that the responsiveness of neonatal adrenals to stimulation by metabolic acidosis is blunted, acidosis therefore, may play a minor role in the neonatal hyperfunction of renin-angiotensin-aldosterone system.

Acidosis↗

[The arrhythmogenicity of alpha 1-adrenergic stimulation following myocardial acidosis].

Ischemia is associated with myocardial acidosis which recovers upon reperfusion. In such conditions, alpha 1-adrenergic stimulation is arrhythmogenic. We used single cardiac myocytes loaded with the pH fluorescent dye, SNARF-1, to determine if a modulation of pH could explain the effect of alpha 1-adrenergic stimulation. Cells were exposed to acidosis (CO2 15%) for 15 min and then normocapnia restored. During acidosis, alpha 1-adrenergic stimulation caused an increase in pH which was abolished by blocking Na+/H+ exchange with ethylisopropylamiloride (EIPA). After removal of acidosis aftercontractions were manifest in 8 out of 10 and 1 out of 5 cells in the presence of an alpha 1-adrenergic agonist and in control, respectively (p < 0.001). EIPA abolished the occurrence of after contractions. Thus, the arrhythmogenicity of alpha 1-adrenergic stimulation depends on activation of Na+/H+ exchanger.

Acidosis↗

Vasopressor agents; influence of acidosis on cardiac and vascular responsiveness.

Clinical observations have indicated that patients who are in shock and who have coexisting acidosis respond relatively poorly to sympathomimetic amines. In experiments with dogs, it was found that, in the presence of acidosis, the pressor action of epinephrine, norepinephrine and metaraminol was considerably reduced. The effect on cardiac rhythm was also considerably lessened after the pH value of the blood had been lowered. In view of these observations in animals, six human patients with profound shock and acidosis were studied. All had a considerably lessened pressor response to vasopressor agents; then, after elevation of the blood pH by intravenous infusion of a 1-molar solution of sodium lactate, responsiveness was restored. These observations emphasize the desirability of close observation of the acid-base status, and early treatment of acidosis, as an important aspect in the management of patients with shock.

Acidosis↗

Metformin-induced lactic acidosis: report of a case.

Lactic acidosis associated with diabetic patients receiving metformin therapy is rare but may cause significant morbidity and mortality. In nearly all reported cases of metformin-associated lactic acidosis, contraindications to its use were noted, especially renal insufficiency. We describe a 59-year-old diabetic man treated with metformin for more than three years. During the third year of use, he experienced progressive renal function impairment, and during the final month of use, he became azotemic. He was maintained on continuous ambulatory peritoneal dialysis. Several days prior to admission, he suffered from epigastralgia, nausea and vomiting, followed by progressive dyspnea which was Kussmaul in nature. Profound hypotension developed and he sank progressively into a coma. Wide-anion gap metabolic acidosis without ketonemia was detected. His blood lactate level was elevated and metformin-induced lactic acidosis was substantiated. An elevated plasma metformin level of greater than 50 mg/mL was determined later by high-performance chromatography. Rigorous treatment including bicarbonate therapy, bicarbonate hemodialysis and vasoactive agents as well as supportive measures were provided. With a return of pH to normal, the hypotension resolved and his consciousness level slowly improved. Our patient survived this disastrous event, but some neurologic sequelae remained. In order to avoid this life-threatening metabolic disturbance, patients with any contraindications should not be prescribed metformin.

Acidosis, Lactic↗

[Diagnosis, countermeasure and classification of acidosis].

Acidosis is the result of the net addition of hydrogen ion to the extracellular space or loss of bicarbonate from that space. Hydrogen ion may be added by the increased production of strong acids, an increase in CO2 concentration, or the addition of exogenous acids. The common approach to the differential diagnosis of metabolic acidosis is to divide the patients into two categories based on whether the anion gap in plasma is increased or not. Metabolic acidosis with normal anion gap (hyperchloremic) suggests that bicarbonate has been effectively replaced by chloride. In contrast, metabolic acidosis with an increased anion gap suggests addition to the body fluids of an acid other than hydrochloric acids or its equivalent.

Acidosis↗

Intrapartum amniotic fluid index and neonatal acidosis. A pilot study to determine the correlation.

The purpose of a prospective study was to determine if there was a significant association between an intrapartum amniotic fluid index (AFI) < or = 5.0 cm and neonatal acidosis (umbilical arterial pH < 7.20 or metabolic acidosis [umbilical arterial pH < 7.20 and base deficit > 10 mEq/L]). In early labor 101 gravidas at > or = 37 gestational weeks underwent a four-quadrant amniotic fluid assessment; at delivery, umbilical arterial acid-base levels were determined. Among women with AFI < or = 5.0 cm as compared to those with AFI > 5.0 cm, the fetuses were more likely to have neonatal acidosis (31.2% versus 17.6%, respectively) and metabolic acidosis (25.0% versus 10.5%, respectively), although the differences were not statistically significant.

Acidosis↗

Acidosis-induced p38 MAPK activation and its implication in regulation of cardiac contractility.

AIM: To determine the possible role of pH in mediating activation of p38 mitogen-activated protein kinase (MAPK) and the consequent function of activated p38 MAPK in regulating cardiac contractility. METHODS: Adult rat cardiomyocytes were isolated and cultured. Low pH media was used to induce intracellular acidosis and contraction of single cardiomyocyte was measured. RESULTS: Phosphorylation of p38 MAPK was increased during ischemia, and pHi was decreased. Intracellular acidosis activated p38 MAPK to a similar level as ischemia. Inhibition of p38 MAPK activation by SB203580, a specific inhibitor of p38 MAPK, reversed acidosis-mediated reduction of myocyte contractility. CONCLUSION: In adult rat cardiomyocytes, intracellular acidification activated p38 MAPK and decreased cardiac contractility. Pretreatment of cardiomyocytes with SB203580 completely blocked p38 MAPK activation and partially reversed acidosis-mediated decline of cardiac contractility.

Acidosis↗

Renal tubular acidosis and severe hypophosphataemia due to toluene inhalation.

A 21-year-old woman developed severe muscle paralysis after sniffing toluene-containing thinner solution for 2 weeks. Her serum chemistries revealed severe hypokalaemia and a normal anion gap hyperchloraemic metabolic acidosis secondary to renal tubular acidosis. Her initial presentation mimicked hypokalaemic periodic paralysis, but toxicology screening of her blood and urine revealed the correct diagnosis of toluene poisoning. Her electrolyte and acid-base status returned to normal 4 days after cessation of toluene sniffing. On another occasion, apart from renal tubular acidosis, the patient also developed severe hypophosphataemia with the phosphate level decreasing to 0.15 mmol/L. Hypophosphataemia with such a low phosphate level after toluene poisoning has been rarely reported in the literature. Toluene inhalation can result in multiple electrolyte and acid-base abnormalities, and should be considered in the diagnosis of any young patient who presents with unexplained hypokalaemia and normal anion gap metabolic acidosis.

Acidosis, Renal Tubular↗