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Non Anion Gap Metabolic Acidosis Treatment

Attending Rounds: Patient With Hypokalemia And Metabolic Acidosis

Attending Rounds: Patient With Hypokalemia And Metabolic Acidosis

Attending Rounds: Patient with Hypokalemia and Metabolic Acidosis Department of Medicine, Yale School of Medicine, New Haven, Connecticut Dr. Asghar Rastegar, Department of Medicine, Yale School of Medicine, 333 Cedar Street, 1074 LMP, P.O. Box 208030, New Haven, CT 06520-8030; Phone: 203-737-2078, Fax: 203-785-7030; E-mail: . Summary Hypokalemic paralysis represents a medical emergency requiring both rapid diagnosis and treatment. In this Attending Rounds a patient with hypokalemia and metabolic acidosis is presented to emphasize the role of routine laboratory studies in the assessment of such patients so that a correct diagnosis can be made and appropriate treatment can be initiated promptly. A 39-year-old woman who had been in excellent health presented with a chief complaint of weakness in her lower extremities. She gave a history of intermittent vomiting for the past 2 months that was worse over the past 3 days. Two weeks before admission she was found to be positive for Helicobacter pylori antigen and was treated with amoxicillin, clarithromycin, and lansoperazole. One day before admission she was seen in the emergency department complaining of 3 days of vomiting. The serum lipase was mildly elevated, and she was diagnosed with mild pancreatitis. The serum potassium concentration was 3.1 mEq/L. She was treated with intravenous fluids and prochlorperazine and sent home. On the day of admission, she noted onset of bilateral lower extremity weakness, inability to walk without a cane, and profound fatigue. She also stated that she had been having intermittent leg cramps and that she recalled having been told previously that she had a low serum potassium level on several occasions. Her past medical history was unremarkable aside from migraine headaches during her mens Continue reading >>

Acid-base Physiology

Acid-base Physiology

8.4.1 Is this the same as normal anion gap acidosis? In hyperchloraemic acidosis, the anion-gap is normal (in most cases). The anion that replaces the titrated bicarbonate is chloride and because this is accounted for in the anion gap formula, the anion gap is normal. There are TWO problems in the definition of this type of metabolic acidosis which can cause confusion. Consider the following: What is the difference between a "hyperchloraemic acidosis" and a "normal anion gap acidosis"? These terms are used here as though they were synonymous. This is mostly true, but if hyponatraemia is present the plasma [Cl-] may be normal despite the presence of a normal anion gap acidosis. This could be considered a 'relative hyperchloraemia'. However, you should be aware that in some cases of normal anion-gap acidosis, there will not be a hyperchloraemia if there is a significant hyponatraemia. In a disorder that typically causes a high anion gap disorder there may sometimes be a normal anion gap! The anion gap may still be within the reference range in lactic acidosis. Now this can be misleading to you when you are trying to diagnose the disorder. Once you note the presence of an anion gap within the reference range in a patient with a metabolic acidosis you naturally tend to concentrate on looking for a renal or GIT cause. 1. One possibility is the increase in anions may be too low to push the anion gap out of the reference range. In lactic acidosis, the clinical disorder can be severe but the lactate may not be grossly high (eg lactate of 6mmol/l) and the change in the anion gap may still leave it in the reference range. So the causes of high anion gap acidosis should be considered in patients with hyperchloraemic acidosis if the cause of the acidosis is otherwise not apparent. Continue reading >>

What Is Metabolic Acidosis?

What Is Metabolic Acidosis?

Metabolic acidosis happens when the chemical balance of acids and bases in your blood gets thrown off. Your body: Is making too much acid Isn't getting rid of enough acid Doesn't have enough base to offset a normal amount of acid When any of these happen, chemical reactions and processes in your body don't work right. Although severe episodes can be life-threatening, sometimes metabolic acidosis is a mild condition. You can treat it, but how depends on what's causing it. Causes of Metabolic Acidosis Different things can set up an acid-base imbalance in your blood. Ketoacidosis. When you have diabetes and don't get enough insulin and get dehydrated, your body burns fat instead of carbs as fuel, and that makes ketones. Lots of ketones in your blood turn it acidic. People who drink a lot of alcohol for a long time and don't eat enough also build up ketones. It can happen when you aren't eating at all, too. Lactic acidosis. The cells in your body make lactic acid when they don't have a lot of oxygen to use. This acid can build up, too. It might happen when you're exercising intensely. Big drops in blood pressure, heart failure, cardiac arrest, and an overwhelming infection can also cause it. Renal tubular acidosis. Healthy kidneys take acids out of your blood and get rid of them in your pee. Kidney diseases as well as some immune system and genetic disorders can damage kidneys so they leave too much acid in your blood. Hyperchloremic acidosis. Severe diarrhea, laxative abuse, and kidney problems can cause lower levels of bicarbonate, the base that helps neutralize acids in blood. Respiratory acidosis also results in blood that's too acidic. But it starts in a different way, when your body has too much carbon dioxide because of a problem with your lungs. Continue reading >>

Metabolic Acidosis; Non-gap

Metabolic Acidosis; Non-gap

Non-gap metabolic acidosis, or hyperchloremic metabolic acidosis, are a group of disorders characterized by a low bicarbonate, hyperchloremia and a normal anion gap (10-12). A non-gapped metabolic acidosis fall into three categories: 1) loss of base (bicarbonate) from the gastrointestinal (GI) tract or 2) loss of base (bicarbonate) from the kidneys, 3) intravenous administration of sodium chloride solution. Bicarbonate can be lost from the GI tract (diarrhea) or from the kidneys (renal tubular acidosis) or displaced by chloride. A. What is the differential diagnosis for this problem? Proximal renal tubular acidosis: (low K+) Distal renal tubular acidosis: (low or high K+) Prostaglandin Inhibitors, (aspirin, nonsteroidal anti-inflammatory drugs, cyclooxygenase 2 inhibitors) Adrenal insufficiency (primary or secondary) (high K+) Pseudoaldosteronism, type 2 (Gordon's syndrome) B. Describe a diagnostic approach/method to the patient with this problem. Metabolic acidosis can be divided into two groups based on anion gap. If an anion gap is elevated (usually greater than 12), see gapped metabolic acidosis. Diagnosis of the cause of non-gapped metabolic acidosis is usually clinically evident - as it can be attributed to diarrhea, intravenous saline or by default, renal tubular acidosis. Occasionally, it may not be clear whether loss of base occurs due to the kidney or bowel. In such a case, one should calculate the urinary anion gap. The urinary anion gap (UAG) = sodium (Na+)+K+- chloride (Cl-). Caution if ketonuria or drug anions are in the urine as it would invalidate the calculation. As an aid, UAG is neGUTive when associated with bowel causes. Non-gapped metabolic acidosis can further be divided into two categories: 1. Historical information important in the diagnosis of Continue reading >>

Normal Anion Gap Acidosis

Normal Anion Gap Acidosis

In renal physiology , normal anion gap acidosis, and less precisely non-anion gap acidosis, is an acidosis that is not accompanied by an abnormally increased anion gap . The most common cause of normal anion gap acidosis is diarrhea with a renal tubular acidosis being a distant second. The differential diagnosis of normal anion gap acidosis is relatively short (when compared to the differential diagnosis of acidosis): Diarrhea : due to a loss of bicarbonate. This is compensated by an increase in chloride concentration, thus leading to a normal anion gap, or hyperchloremic, metabolic acidosis. The pathophysiology of increased chloride concentration is the following: fluid secreted into the gut lumen contains higher amounts of Na+ than Cl; large losses of these fluids, particularly if volume is replaced with fluids containing equal amounts of Na+ and Cl, results in a decrease in the plasma Na+ concentration relative to the Clconcentration. This scenario can be avoided if formulations such as lactated Ringers solution are used instead of normal saline to replace GI losses. [2] Continue reading >>

Metabolic Acidosis: Pathophysiology, Diagnosis And Management: Causes Of Metabolic Acidosis

Metabolic Acidosis: Pathophysiology, Diagnosis And Management: Causes Of Metabolic Acidosis

Recommendations for the treatment of acute metabolic acidosis Gunnerson, K. J., Saul, M., He, S. & Kellum, J. Lactate versus non-lactate metabolic acidosis: a retrospective outcome evaluation of critically ill patients. Crit. Care Med. 10, R22-R32 (2006). Eustace, J. A., Astor, B., Muntner, P M., Ikizler, T. A. & Coresh, J. Prevalence of acidosis and inflammation and their association with low serum albumin in chronic kidney disease. Kidney Int. 65, 1031-1040 (2004). Kraut, J. A. & Kurtz, I. Metabolic acidosis of CKD: diagnosis, clinical characteristics, and treatment. Am. J. Kidney Dis. 45, 978-993 (2005). Kalantar-Zadeh, K., Mehrotra, R., Fouque, D. & Kopple, J. D. Metabolic acidosis and malnutrition-inflammation complex syndrome in chronic renal failure. Semin. Dial. 17, 455-465 (2004). Kraut, J. A. & Kurtz, I. Controversies in the treatment of acute metabolic acidosis. NephSAP 5, 1-9 (2006). Cohen, R. M., Feldman, G. M. & Fernandez, P C. The balance of acid base and charge in health and disease. Kidney Int. 52, 287-293 (1997). Rodriguez-Soriano, J. & Vallo, A. Renal tubular acidosis. Pediatr. Nephrol. 4, 268-275 (1990). Wagner, C. A., Devuyst, O., Bourgeois, S. & Mohebbi, N. Regulated acid-base transport in the collecting duct. Pflugers Arch. 458, 137-156 (2009). Boron, W. F. Acid base transport by the renal proximal tubule. J. Am. Soc. Nephrol. 17, 2368-2382 (2006). Igarashi, T., Sekine, T. & Watanabe, H. Molecular basis of proximal renal tubular acidosis. J. Nephrol. 15, S135-S141 (2002). Sly, W. S., Sato, S. & Zhu, X. L. Evaluation of carbonic anhydrase isozymes in disorders involving osteopetrosis and/or renal tubular acidosis. Clin. Biochem. 24, 311-318 (1991). Dinour, D. et al. A novel missense mutation in the sodium bicarbonate cotransporter (NBCe1/ SLC4A4) Continue reading >>

Metabolic Acidosis - Endocrine And Metabolic Disorders - Merck Manuals Professional Edition

Metabolic Acidosis - Endocrine And Metabolic Disorders - Merck Manuals Professional Edition

(Video) Overview of Acid-Base Maps and Compensatory Mechanisms By James L. Lewis, III, MD, Attending Physician, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham Metabolic acidosis is primary reduction in bicarbonate (HCO3−), typically with compensatory reduction in carbon dioxide partial pressure (Pco2); pH may be markedly low or slightly subnormal. Metabolic acidoses are categorized as high or normal anion gap based on the presence or absence of unmeasured anions in serum. Causes include accumulation of ketones and lactic acid, renal failure, and drug or toxin ingestion (high anion gap) and GI or renal HCO3− loss (normal anion gap). Symptoms and signs in severe cases include nausea and vomiting, lethargy, and hyperpnea. Diagnosis is clinical and with ABG and serum electrolyte measurement. The cause is treated; IV sodium bicarbonate may be indicated when pH is very low. Metabolic acidosis is acid accumulation due to Increased acid production or acid ingestion Acidemia (arterial pH < 7.35) results when acid load overwhelms respiratory compensation. Causes are classified by their effect on the anion gap (see The Anion Gap and see Table: Causes of Metabolic Acidosis ). Lactic acidosis (due to physiologic processes) Lactic acidosis (due to exogenous toxins) Toluene (initially high gap; subsequent excretion of metabolites normalizes gap) HIV nucleoside reverse transcriptase inhibitors Biguanides (rare except with acute kidney injury) Normal anion gap (hyperchloremic acidosis) Renal tubular acidosis, types 1, 2, and 4 The most common causes of a high anion gap metabolic acidosis are Ketoacidosis is a common complication of type 1 diabetes mellitus (see diabetic ketoacidosis ), but it also occurs with chronic alcoholism (see alcoholic ketoacidos Continue reading >>

Therapy 3 Acid Base Disorders

Therapy 3 Acid Base Disorders

O2 sat and PO2 does NOT affect acid-base balance Anion gap: measure that expresses the balance between circulating anions and cations [AG = Na - (HCO3 + Cl)] Recognize common causes, including medications, of primary acid-base disturbances 1. Anion gap (non volatile organic aicds) : albumin, Na, lipids, lithium 2. non-anion gap (only HCO3 and Cl involved) a. Drug - induced hyperkalemia: K-sparring diuretics, TMP, Heparin, ACE, ARB Recognize the presence and degree of physiologic compensation of acid base disorders Acute buffering of respiratory acidosis is accomplished by tissue buffers (protein, hemoglobin) Lungs adjust minute ventilation (rate and tidal volume) to change [CO2] to compensate for metabolic disorders Kidneys retain or excrete bicarbonate to compensate for changes in [CO2] Identify appropriate patient cases where treatment of acid-base disorders is indicated a. Treatment of reversible cause (ex. opioid discontinuation) b. Mechanical ventilation to aid in CO2 exchange c. NOT give sodium bicarbonate- Shift in equilibrium will result in more CO2 production d. Last line: May give THAM if unresponsive to ventilation 2. Chronic, compensated respiratory acidosis does not require treatment 1. Acute non-anion gap metabolic acidosis may require treatment to replace bicarbonate deficit a. Bicarbonate deficit can be corrected orally over hours to days 2. Chronic metabolic acidosis does not usually require emergent therapy 1. Treatment centers on correcting the underlying disorder 2. NON-effective: Giving bicarbonate only shifts the carbonic acid/bicarbonate buffer system to generating CO2 3. Often will correct numbers but NOT the underlying cause 2. Type 2 & 3: NO benefit from bicarb therapy Calculate a bicarbonate or other alkali replacement dose for an appropriate Continue reading >>

High Anion Gap Metabolic Acidosis - Today's Pearl - Statpearls

High Anion Gap Metabolic Acidosis - Today's Pearl - Statpearls

High anion gap metabolic acidosis (HAGMA) is a subcategory of acidosis ofmetabolic (i.e., non-respiratory) etiology. Differentiation of acidosis into a particular subtype, whether high anion gap metabolic acidosisor non-aniongap metabolic acidosis(NAGMA), aids in the determinationof the etiology and hence appropriate treatment. Although there have been many broadly inclusive mnemonic devices for high anion gap metabolic acidosis, the use of "GOLD MARK" has gained popularity for its focus on causes common to the 21st century. Glycols (ethylene glycol, propylene glycol) Oxoproline (pyroglutamic acid, the toxic metabolite of excessive acetaminophen or paracetamol) L-Lactate (standard lactic acid seen in lactic acidosis) D-Lactate (exogenous lactic acid produced by gut bacteria) Methanol (this is inclusive of alcohols in general) Ketones (diabetic, alcoholic and starvation ketosis) Of note, metformin has been omitted from this list due to a lack of evidence for metformin-induced lactic acidosis. In fact, aCochrane review found substantial evidence that metformin was not a cause of lactic acidosis. The same could not be said ofthe older biguanide, phenformin, which does increase the incidence of lactic acidosis by approximately tenfold. Furthermore, the addition of massive rhabdomyolysis would be appropriate given the potentially large amounts of hydrogen ions released by muscle breakdown. High anion gap metabolic acidosis is one of the most common metabolic derangements seen in critical care patients. Exact numbers are not readily available. The most common method of evaluation of metabolic acidosis involves the Henderson-Hasselbalch equation and the Lewis model interpretation of biological acidosis which evaluates the plasma concentration of hydrogen ions. An alternative Continue reading >>

Normal Anion Gap Acidosis

Normal Anion Gap Acidosis

Terry W. Hensle, Erica H. Lambert, in Pediatric Urology , 2010 Nonanion gap acidosis occurs in situations in which HCO3 is lost from the kidney or the gastrointestinal tract or both. When this occurs, Cl (along with Na+) is reabsorbed to replace the HCO3; this leads to the hyperchloremia, which leaves the anion gap in normal range.10 Diarrhea causes a hyperchloremic, hypokalemic metabolic acidosis. Treatment depends on the severity of the acidosis incurred. In mild to moderate acidosis (pH >7.2), fluid and electrolyte replacement is often all that is required. Once adequate renal perfusion is restored, excess H+ can be excreted efficiently, restoring the pH to normal. In severe acidosis (pH <7.2), the addition of intravenous bicarbonate may be needed to correct the metabolic deficit. Before bicarbonate is administered, a serum potassium level should be obtained. The addition of bicarbonate can worsen hypokalemia, leading to neuromuscular complications. Hyperchloremic acidosis also occurs with renal insufficiency and renal tubular acidosis.9,20 Katherine Ahn Jin, in Comprehensive Pediatric Hospital Medicine , 2007 As in any condition, the first priority in management is stabilizing the ABCs, as necessary. Management of metabolic acidosis is directed toward treating the underlying cause. In general, treating the causes of anion gap acidosis can regenerate bicarbonate within hours; however, nonanion gap acidosis can take days to resolve and may require exogenous bicarbonate therapy. Insulin, hydration, and electrolyte repletion will correct the acidosis in diabetic ketoacidosis. In addition to treating the underlying condition, lactic acidosis can be resolved by increasing tissue oxygenation using crystalloid, blood products, afterload reduction, inotropic agents (e.g., d Continue reading >>

Approach To The Adult With Metabolic Acidosis

Approach To The Adult With Metabolic Acidosis

INTRODUCTION On a typical Western diet, approximately 15,000 mmol of carbon dioxide (which can generate carbonic acid as it combines with water) and 50 to 100 mEq of nonvolatile acid (mostly sulfuric acid derived from the metabolism of sulfur-containing amino acids) are produced each day. Acid-base balance is maintained by pulmonary and renal excretion of carbon dioxide and nonvolatile acid, respectively. Renal excretion of acid involves the combination of hydrogen ions with urinary titratable acids, particularly phosphate (HPO42- + H+ —> H2PO4-), and ammonia to form ammonium (NH3 + H+ —> NH4+) [1]. The latter is the primary adaptive response since ammonia production from the metabolism of glutamine can be appropriately increased in response to an acid load [2]. Acid-base balance is usually assessed in terms of the bicarbonate-carbon dioxide buffer system: Dissolved CO2 + H2O <—> H2CO3 <—> HCO3- + H+ The ratio between these reactants can be expressed by the Henderson-Hasselbalch equation. By convention, the pKa of 6.10 is used when the dominator is the concentration of dissolved CO2, and this is proportional to the pCO2 (the actual concentration of the acid H2CO3 is very low): TI AU Garibotto G, Sofia A, Robaudo C, Saffioti S, Sala MR, Verzola D, Vettore M, Russo R, Procopio V, Deferrari G, Tessari P To evaluate the effects of chronic metabolic acidosis on protein dynamics and amino acid oxidation in the human kidney, a combination of organ isotopic ((14)C-leucine) and mass-balance techniques in 11 subjects with normal renal function undergoing venous catheterizations was used. Five of 11 studies were performed in the presence of metabolic acidosis. In subjects with normal acid-base balance, kidney protein degradation was 35% to 130% higher than protein synthesi Continue reading >>

The Anion Gap

The Anion Gap

The anion gap is a tool used to: Confirm that an acidosis is indeed metabolic Narrow down the cause of a metabolic acidosis Monitor the progress of treatment In a metabolic acidosis the anion gap is usually either ‘Normal’ or ‘High’. In rare cases it can be ‘low’, usually due to hypoalbuminaemia. An ABG machine will often give a print out of the anion gap, but it can also be useful to know how it is calculated. In blood, there are many cations and anions. However, the vast majority of the total number are potassium, sodium, chloride, or bicarbonate. The ‘anion’ gap is an artificial measure, which is calculated by subtracting the total number of anions (negatively charged ions – bicarbonate and chloride) from the total number of cations (sodium and potassium). Thus, the formula is: ([Na+]+ [K+]) –([Cl–]+ [HCO3–]) In reality, the concentration of potassium anions is negligible, and this often omitted. There are usually more measurable cations than anions, and thus a normal anion gap is value is positive. A normal value is usually 3-16, but may vary slightly depending on the technique used by the local laboratory. If the anion gap is <30, then there may not be ‘true’ high anion gap metabolic acidosis. In a healthy normal individual, the main unmeasured anions are albumin and phosphate. Almost all of the gap can be attributed to albumin. This means that in patients with hypoalbuminaemia and metabolic acidosis, there may be a normal anion gap. Be wary in severely unwell patients because they often have a low albumin. You can adjust for this in your calculation. Corrected anion gap: [AG] + (0.25 x (40-albumin)) In an unwell patient with a high anion gap metabolic acidosis (HAGMA) the anion gap is increased due: Accumulation of organic acids Inabili Continue reading >>

Is Correcting Hyperchloremic Acidosis Beneficial?

Is Correcting Hyperchloremic Acidosis Beneficial?

You are here: Home / PULMCrit / Is correcting hyperchloremic acidosis beneficial? Is correcting hyperchloremic acidosis beneficial? An elderly woman presents with renal failure due to severe dehydration from diarrhea. She has a hyperchloremic acidosis from diarrhea with a chloride of 115 mEq/L, bicarbonate of 15 mEq/L, and a normal anion gap. During her volume resuscitation, should isotonic bicarbonate be used to correct her hyperchloremic acidosis? Does correcting her hyperchloremic acidosis actually help her, or does this just make her numbers better? The use of bicarbonate for treatment of metabolic acidosis is controversial. However, this controversy centers primarily around use of bicarbonate for management of lactic acidosis or ketoacidosis.Treatment of these disorders requires reversing the underlying disease process, with bicarbonate offering little if any benefit.Hyperchloremic metabolic acidosis is different.Whether due to bicarbonate loss or volume repletion with normal saline, the primary problems is a bicarbonate deficiency.Treating this with bicarbonate is a logical and accepted approach: Giving bicarbonate to a patient with a true bicarbonate deficit is not controversial. Controversy arises when the decrease in bicarbonate concentration is the result of its conversion to another base, which, given time, can be converted back to bicarbonate However, clinicians are often reluctant to treat hyperchloremic metabolic acidosis with bicarbonate, since the benefits of treatment are unclear.This post will attempt to clarify the rationale for treatment. Resuscitation with balanced crystalloids improves renal function There is growing evidence that resuscitation with normal saline impairs renal blood flow and function ( Young 2014 ).For example, Chowdhury 2012 inve Continue reading >>

Metabolic Acidosis Treatment & Management

Metabolic Acidosis Treatment & Management

Approach Considerations Treatment of acute metabolic acidosis by alkali therapy is usually indicated to raise and maintain the plasma pH to greater than 7.20. In the following two circumstances this is particularly important. When the serum pH is below 7.20, a continued fall in the serum HCO3- level may result in a significant drop in pH. This is especially true when the PCO2 is close to the lower limit of compensation, which in an otherwise healthy young individual is approximately 15 mm Hg. With increasing age and other complicating illnesses, the limit of compensation is likely to be less. A further small drop in HCO3- at this point thus is not matched by a corresponding fall in PaCO2, and rapid decompensation can occur. For example, in a patient with metabolic acidosis with a serum HCO3- level of 9 mEq/L and a maximally compensated PCO2 of 20 mm Hg, a drop in the serum HCO3- level to 7 mEq/L results in a change in pH from 7.28 to 7.16. A second situation in which HCO3- correction should be considered is in well-compensated metabolic acidosis with impending respiratory failure. As metabolic acidosis continues in some patients, the increased ventilatory drive to lower the PaCO2 may not be sustainable because of respiratory muscle fatigue. In this situation, a PaCO2 that starts to rise may change the plasma pH dramatically even without a significant further fall in HCO3-. For example, in a patient with metabolic acidosis with a serum HCO3- level of 15 and a compensated PaCO2 of 27 mm Hg, a rise in PaCO2 to 37 mm Hg results in a change in pH from 7.33 to 7.20. A further rise of the PaCO2 to 43 mm Hg drops the pH to 7.14. All of this would have occurred while the serum HCO3- level remained at 15 mEq/L. In lactic acidosis and diabetic ketoacidosis, the organic anion can r Continue reading >>

Hyperchloremic Acidosis

Hyperchloremic Acidosis

Normal albumin-corrected anion gap acidosis Hyperchloremic acidosis is a common acid-base disturbance in critical illness, often mild (standard base excess >-10 mEq/L). Definitions of hyperchloremic acidosis vary. The best are not based on chloride concentrations, but on the presence of metabolic acidosis plus the absence of significant concentrations of lactate or other unmeasured anions. 2. standard base excess less than -3 mEq/L or bicarbonate less than 22 mmol/L, 3. Albumin corrected anion gap normal (5-15 mEq/L). A normal strong ion gap is an alternative indicator of the absence of unmeasured anions, although rarely used clinically and offering little advantage over the albumin corrected anion gap. The degree of respiratory compensation is relevant. It is appropriate if PaCO2 approximates the two numbers after arterial pH decimal point (e.g. pH=7.25, PaCO2=25 mm Hg; this rule applies to any primary metabolic acidosis down to a pH of 7.1). Acidosis is severe if standard base excess is less than -10 mEq/L, or pH is less than 7.3, or bicarbonate is less than 15 mmol/L. Common causes in critical illness are large volume saline administration, large volume colloid infusions (e.g. unbalanced gelatine or starch preparations) following resolution of diabetic keto-acidosis or of other raised anion gap acidosis, and post hypocarbia. Hyperchloremic acidosis often occurs on a background of renal impairment/tubular dysfunction. It is usually well tolerated, especially with appropriate respiratory compensation. The prognosis is largely that of the underlying condition. If associated with hyperkalemia, think of hypo-aldosteronism (Type 4 RTA), especially if diabetic. With persistent hypokalemia, think of RTA Types 1 and 2. Hyperchloremic acidosis is usually well tolerated in the Continue reading >>

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