Anion Gap

Acidosis is a common and deleterious aspect of maintenance dialysis. Traditionally, it is considered to be an elevated anion gap acidosis caused by the inability to excrete nonvolatile anions. Stewart's approach made it possible to identify real determinants of the acid-base status and allowed quantification of the components of these disturbances, especially the unmeasured anions. We performed a cross-sectional study to identify and quantify each component of acidosis in hemodialysis maintenance patients. Sixty-four maintenance hemodialysis patients and 14 controls were enrolled in this study. Gasometrical and biochemical analysis were performed before the midweek dialysis session. Quantitative physicochemical analysis was carried out using the Stewart methodology. Hemodialysis patients were found to have mild acidemia (mean pH: 7.33 +/- 0.06 versus 7.41 +/- 0.05) secondary to metabolic acidosis (serum bicarbonate: 18.8 +/- 0.26 versus 25.2 +/- 0.48 mEq/l). The metabolic acidos...

Acid-base abnormalities are common in critically ill patients. Our ability to describe acid-base disorders must be precise. Small differences in corrections for anion gap, different types of analytical processes, and the basic approach used to diagnose acid-base aberrations can lead to markedly different interpretations and treatment strategies for the same disorder. By applying a quantitive acid-base approach, clinicians are able to account for small changes in ion distribution that may have gone unrecognized with traditional techniques of acid-base analysis. Outcome prediction based on the quantitative approach remains controversial. This is in part due to use of various technologies to measure acid-base variables, administration of fluid or medication that can alter acid-base results, and lack of standardized nomenclature. Without controlling for these factors it is difficult to appreciate the full effect that acid-base disorders have on patient outcomes, ultimately making result...

Metabolic acidosis secondary to lactic acidosis may occur in acute, severe asthma and its presence suggests that respiratory muscle fatigue and tissue hypoxia play a major part in the pathogenesis. Non-anion gap metabolic acidosis (NAG acidosis) has also been reported in acute asthma but its impact on the clinical outcome has not been evaluated. The objective of this study was to evaluate the prevalence of NAG acidosis, characterize the laboratory findings, and determine its impact on clinical outcomes. Acid-base and electrolyte status and clinical outcomes were examined over a 1-yr (2005 calendar yr) period in 109 adult patients (38 males, 71 females; age range 21 to 91 yr) hospitalized for asthma exacerbation. The cohort was divided into 3 groups: I. No metabolic acidosis (n = 66), II. Anion gap (AG) acidosis (n = 11), and III. NAG acidosis (n = 32). For each of the groups, laboratory findings were consistent, demonstrating a tendency to hyperchloremia in the NAG acidosis group. O...

Objective: To assess the efficacy and safety of fomepizole, a competitive alcohol dehydrogenase inhibitor, in methanol poisoning and to test the hypothesis that fomepizole obviates the need for hemodialysis in selected patients. Design and setting: Retrospective clinical study in three intensive care units in university-affiliated teaching hospitals. Patients: All methanol-poisoned patients admitted to these ICUs and treated with fomepizole from

The effects of NaHCO3 and glucose on ruminal fermentation, acid-base balance and blood chemistry were assessed in sheep fed with 60% of concentrated. Four ruminally cannulated sheep (65 ± 10 kg initial BW) were used in a cross-over design in metabolic crates. Sheep were fed with a total mixed ration (concentrate 60% and forage 40%). Each period included adaptation of

Mixed metabolic-respiratory acid-base disorders may be diagnosed when the respiratory compensation for a primary metabolic acidosis or alkalosis is inappropriate or when there is inappropriate metabolic compensation for a primary respiratory disorder. The magnitude of the primary change in HCO3 concentration (in metabolic disorders) defines the limits of compensation. We emphasized the importance of the equality of the increment in the anion gap (delta AG) and the decrement in the serum bicarbonate concentration (delta HCO3) in diagnosing a simple high AG metabolic acidosis. The close relationship between these two changes in simple high AG acidoses is reviewed. When the delta HCO3 is greater than the delta AG, we suggest that a mixed high AG and hyperchloraemic acidosis is present. Other possible interpretations of these chemical changes are discussed. When the delta HCO3 is less than the delta AG, a mixed metabolic alkalosis and metabolic acidosis is likely to be present, but othe...

Pregnancy is a diabetogenic state characterized by relative insulin resistance, enhanced lipolysis, elevated free fatty acids and increased ketogenesis. In this setting, short period of starvation can precipitate ketoacidosis. This sequence of events is recognized as “accelerated starvation.” Metabolic acidosis during pregnancy may have adverse impact on fetal neural development including impaired intelligence and fetal demise. Short periods of starvation during pregnancy may present as severe anion gap metabolic acidosis (AGMA). We present a 41-year-old female in her 32nd week of pregnancy, admitted with severe AGMA with pH 7.16, anion gap 31, and bicarbonate of 5 mg/dL with normal lactate levels. She was intubated and accepted to medical intensive care unit. Urine and serum acetone were positive. Evaluation for all causes of AGMA was negative. The diagnosis of starvation ketoacidosis was established in absence of other causes of AGMA. Intravenous fluids, dextrose, thiamine, and fo...

♦ ♦ ♦ ♦ ♦ Objective: To investigate the association of clinical pa- rameters and serum anion gap with thyroid dysfunction and nodular goiter in continuous ambulatory peritoneal dialysis (CAPD) patients. ♦ ♦ ♦ ♦ ♦ Design: Cross-sectional study. ♦ ♦ ♦ ♦ ♦ Setting: Single dialysis unit and outpatient clinic. ♦ ♦ ♦ ♦ ♦ Patients: This study included 89 uremic patients on CAPD. Gender ratio was 50 males to 39 females (M/F = 1.28); mean age was 54.8 years. ♦ ♦ ♦ ♦ ♦ Main Outcome Measures: We investigated the preva- lence of nodular goiter and thyroid dysfunction with a 10-MHz high-frequency ultrasound scanner and immu- noassay kits. ♦ ♦ ♦ ♦ ♦ Results: Nodular goiter was detected in 52.8% (47/89) of the CAPD patients. Patients with nodular goiter were older than those without goiter (57.7 vs 51.5 years, p < 0.05). Nodular goiter was found more frequently in females than in males (66.7% vs 44.0%, p < 0.05). Patients with nodular goiter had longer duration of CAPD than patients without ...

Ethylene glycol poisoning is an important toxicological problem in medical practice because early diagnosis and treatment can prevent considerable morbidity and mortality. When ingested in the form of antifreeze or other automotive products, ethylene glycol results in central nervous system depression, cardiopulmonary compromise, and renal insufficiency. Metabolism of ethylene glycol to organic acids is required for metabolic derangement and organ damage. Laboratory features of ethylene glycol poisoning include increased anion gap metabolic acidosis, increased osmolal gap, calcium oxalate crystalluria, and detectable ethylene glycol in serum. This Case Conference integrates discussion of the toxicokinetic and analytical variables that affect the laboratory diagnosis of ethylene glycol intoxication.