diabetestalk.net

Respiratory And Metabolic Acidosis And Alkalosis

Acid-base Disorders

Acid-base Disorders

Content currently under development Acid-base disorders are a group of conditions characterized by changes in the concentration of hydrogen ions (H+) or bicarbonate (HCO3-), which lead to changes in the arterial blood pH. These conditions can be categorized as acidoses or alkaloses and have a respiratory or metabolic origin, depending on the cause of the imbalance. Diagnosis is made by arterial blood gas (ABG) interpretation. In the setting of metabolic acidosis, calculation of the anion gap is an important resource to narrow down the possible causes and reach a precise diagnosis. Treatment is based on identifying the underlying cause. Continue reading >>

Acid Base Disorders

Acid Base Disorders

Arterial blood gas analysis is used to determine the adequacy of oxygenation and ventilation, assess respiratory function and determine the acid–base balance. These data provide information regarding potential primary and compensatory processes that affect the body’s acid–base buffering system. Interpret the ABGs in a stepwise manner: Determine the adequacy of oxygenation (PaO2) Normal range: 80–100 mmHg (10.6–13.3 kPa) Determine pH status Normal pH range: 7.35–7.45 (H+ 35–45 nmol/L) pH <7.35: Acidosis is an abnormal process that increases the serum hydrogen ion concentration, lowers the pH and results in acidaemia. pH >7.45: Alkalosis is an abnormal process that decreases the hydrogen ion concentration and results in alkalaemia. Determine the respiratory component (PaCO2) Primary respiratory acidosis (hypoventilation) if pH <7.35 and HCO3– normal. Normal range: PaCO2 35–45 mmHg (4.7–6.0 kPa) PaCO2 >45 mmHg (> 6.0 kPa): Respiratory compensation for metabolic alkalosis if pH >7.45 and HCO3– (increased). PaCO2 <35 mmHg (4.7 kPa): Primary respiratory alkalosis (hyperventilation) if pH >7.45 and HCO3– normal. Respiratory compensation for metabolic acidosis if pH <7.35 and HCO3– (decreased). Determine the metabolic component (HCO3–) Normal HCO3– range 22–26 mmol/L HCO3 <22 mmol/L: Primary metabolic acidosis if pH <7.35. Renal compensation for respiratory alkalosis if pH >7.45. HCO3 >26 mmol/L: Primary metabolic alkalosis if pH >7.45. Renal compensation for respiratory acidosis if pH <7.35. Additional definitions Osmolar Gap Use: Screening test for detecting abnormal low MW solutes (e.g. ethanol, methanol & ethylene glycol [Reference]) An elevated osmolar gap (>10) provides indirect evidence for the presence of an abnormal solute which is prese Continue reading >>

Simple Method Of Acid Base Balance Interpretation

Simple Method Of Acid Base Balance Interpretation

A FOUR STEP METHOD FOR INTERPRETATION OF ABGS Usefulness This method is simple, easy and can be used for the majority of ABGs. It only addresses acid-base balance and considers just 3 values. pH, PaCO2 HCO3- Step 1. Use pH to determine Acidosis or Alkalosis. ph < 7.35 7.35-7.45 > 7.45 Acidosis Normal or Compensated Alkalosis Step 2. Use PaCO2 to determine respiratory effect. PaCO2 < 35 35 -45 > 45 Tends toward alkalosis Causes high pH Neutralizes low pH Normal or Compensated Tends toward acidosis Causes low pH Neutralizes high pH Step 3. Assume metabolic cause when respiratory is ruled out. You'll be right most of the time if you remember this simple table: High pH Low pH Alkalosis Acidosis High PaCO2 Low PaCO2 High PaCO2 Low PaCO2 Metabolic Respiratory Respiratory Metabolic If PaCO2 is abnormal and pH is normal, it indicates compensation. pH > 7.4 would be a compensated alkalosis. pH < 7.4 would be a compensated acidosis. These steps will make more sense if we apply them to actual ABG values. Click here to interpret some ABG values using these steps. You may want to refer back to these steps (click on "linked" steps or use "BACK" button on your browser) or print out this page for reference. Step 4. Use HC03 to verify metabolic effect Normal HCO3- is 22-26 Please note: Remember, the first three steps apply to the majority of cases, but do not take into account: the possibility of complete compensation, but those cases are usually less serious, and instances of combined respiratory and metabolic imbalance, but those cases are pretty rare. "Combined" disturbance means HCO3- alters the pH in the same direction as the PaCO2. High PaCO2 and low HCO3- (acidosis) or Low PaCO2 and high HCO3- (alkalosis). Continue reading >>

Uncompensated, Partially Compensated, Or Combined Abg Problems

Uncompensated, Partially Compensated, Or Combined Abg Problems

Arterial Blood Gas (ABG) analysis requires in-depth expertise. If the results are not understood right, or are wrongly interpreted, it can result in wrong diagnosis and end up in an inappropriate management of the patient. ABG analysis is carried out when the patient is dealing with the following conditions: • Breathing problems • Lung diseases (asthma, cystic fibrosis, COPD) • Heart failure • Kidney failure ABG reports help in answering the following questions: 1. Is there acidosis or alkalosis? 2. If acidosis is present, whether it is in an uncompensated state, partially compensated state, or in fully compensated state? 3. Whether acidosis is respiratory or metabolic? ABG reports provide the following descriptions: PaCO2 (partial pressure of dissolved CO2 in the blood) and PaO2 (partial pressure of dissolved O2 in the blood) describe the efficiency of exchange of gas in the alveolar level into the blood. Any change in these levels causes changes in the pH. HCO3 (bicarbonate in the blood) maintains the pH of the blood within normal range by compensatory mechanisms, which is either by retaining or increasing HCO3 excretion by the kidney. When PaCO2 increases, HCO3 decreases to compensate the pH. The following table summarizes the changes: ABG can be interpreted using the following analysis points: Finding acidosis or alkalosis: • If pH is more it is acidosis, if pH is less it is alkalosis. Finding compensated, partially compensated, or uncompensated ABG problems: • When PaCO2 is high, but pH is normal instead of being acidic, and if HCO3 levels are also increased, then it means that the compensatory mechanism has retained more HCO3 to maintain the pH. • When PaCO2 and HCO3 values are high but pH is acidic, then it indicates partial compensation. It means t Continue reading >>

Disorders Of Acid-base Balance

Disorders Of Acid-base Balance

Module 10: Fluid, Electrolyte, and Acid-Base Balance By the end of this section, you will be able to: Identify the three blood variables considered when making a diagnosis of acidosis or alkalosis Identify the source of compensation for blood pH problems of a respiratory origin Identify the source of compensation for blood pH problems of a metabolic/renal origin Normal arterial blood pH is restricted to a very narrow range of 7.35 to 7.45. A person who has a blood pH below 7.35 is considered to be in acidosis (actually, physiological acidosis, because blood is not truly acidic until its pH drops below 7), and a continuous blood pH below 7.0 can be fatal. Acidosis has several symptoms, including headache and confusion, and the individual can become lethargic and easily fatigued. A person who has a blood pH above 7.45 is considered to be in alkalosis, and a pH above 7.8 is fatal. Some symptoms of alkalosis include cognitive impairment (which can progress to unconsciousness), tingling or numbness in the extremities, muscle twitching and spasm, and nausea and vomiting. Both acidosis and alkalosis can be caused by either metabolic or respiratory disorders. As discussed earlier in this chapter, the concentration of carbonic acid in the blood is dependent on the level of CO2 in the body and the amount of CO2 gas exhaled through the lungs. Thus, the respiratory contribution to acid-base balance is usually discussed in terms of CO2 (rather than of carbonic acid). Remember that a molecule of carbonic acid is lost for every molecule of CO2 exhaled, and a molecule of carbonic acid is formed for every molecule of CO2 retained. Figure 1. Symptoms of acidosis affect several organ systems. Both acidosis and alkalosis can be diagnosed using a blood test. Metabolic Acidosis: Primary Bic Continue reading >>

Metabolic Acidosis Or Respiratory Alkalosis? Evaluation Of A Low Plasmabicarbonate Using The Urine Anion Gap.

Metabolic Acidosis Or Respiratory Alkalosis? Evaluation Of A Low Plasmabicarbonate Using The Urine Anion Gap.

1. Am J Kidney Dis. 2017 Sep;70(3):440-444. doi: 10.1053/j.ajkd.2017.04.017. Epub2017 Jun 7. Metabolic Acidosis or Respiratory Alkalosis? Evaluation of a Low PlasmaBicarbonate Using the Urine Anion Gap. Batlle D(1), Chin-Theodorou J(2), Tucker BM(3). (1)Division of Nephrology & Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL. Electronic address: [email protected] (2)Division of Nephrology & Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL. (3)Section of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, CT. Hypobicarbonatemia, or a reduced bicarbonate concentration in plasma, is afinding seen in 3 acid-base disorders: metabolic acidosis, chronic respiratoryalkalosis and mixed metabolic acidosis and chronic respiratory alkalosis.Hypobicarbonatemia due to chronic respiratory alkalosis is often misdiagnosed as a metabolic acidosis and mistreated with the administration of alkali therapy.Proper diagnosis of the cause of hypobicarbonatemia requires integration of thelaboratory values, arterial blood gas, and clinical history. The informationderived from the urinary response to the prevailing acid-base disorder is useful to arrive at the correct diagnosis. We discuss the use of urine anion gap, as asurrogate marker of urine ammonium excretion, in the evaluation of a patient withlow plasma bicarbonate concentration to differentiate between metabolic acidosis and chronic respiratory alkalosis. The interpretation and limitations of urineacid-base indexes at bedside (urine pH, urine bicarbonate, and urine anion gap)to evaluate urine acidification are discussed.Copyright 2017 National Kidney Foundation, Inc. Published by E Continue reading >>

Metabolic Alkalosis

Metabolic Alkalosis

Practice Essentials Metabolic alkalosis is a primary increase in serum bicarbonate (HCO3-) concentration. This occurs as a consequence of a loss of H+ from the body or a gain in HCO3-. In its pure form, it manifests as alkalemia (pH >7.40). As a compensatory mechanism, metabolic alkalosis leads to alveolar hypoventilation with a rise in arterial carbon dioxide tension (PaCO2), which diminishes the change in pH that would otherwise occur. Normally, arterial PaCO2 increases by 0.5-0.7 mm Hg for every 1 mEq/L increase in plasma bicarbonate concentration, a compensatory response that is very quick. If the change in PaCO2 is not within this range, then a mixed acid-base disturbance occurs. For example, if the increase in PaCO2 is more than 0.7 times the increase in bicarbonate, then metabolic alkalosis coexists with primary respiratory acidosis. Likewise, if the increase in PaCO2 is less than the expected change, then a primary respiratory alkalosis is also present. The first clue to metabolic alkalosis is often an elevated bicarbonate concentration that is observed when serum electrolyte measurements are obtained. Remember that an elevated serum bicarbonate concentration may also be observed as a compensatory response to primary respiratory acidosis. However, a bicarbonate concentration greater than 35 mEq/L is almost always caused by metabolic alkalosis. Metabolic alkalosis is diagnosed by measuring serum electrolytes and arterial blood gases. If the etiology of metabolic alkalosis is not clear from the clinical history and physical examination, including drug use and the presence of hypertension, then a urine chloride ion concentration can be obtained. Calculation of the serum anion gap may also help to differentiate between primary metabolic alkalosis and metabolic compe Continue reading >>

Abg: Respiratory Acidosis/metabolic Alkalosis

Abg: Respiratory Acidosis/metabolic Alkalosis

Home / ABA Keyword Categories / A / ABG: Respiratory acidosis/metabolic alkalosis ABG: Respiratory acidosis/metabolic alkalosis A combined respiratory acidosis / metabolic alkalosis will result in elevated PaCO2 and serum bicarbonate. Which process is the primary disorder (e.g. primary respiratory acidosis with metabolic compensation versus primary metabolic alkalosis with respiratory compensation) is dependent on the pH in an acidotic patient, the acidosis is primary (and the alkalosis is compensatory) and vice versa. Compensation behaves in accordance with the following rules: Metabolic Acidosis: As bicarbonate goes from 10 to 5, pCO2 will bottom out at 15. pCO2 = 1.5 x [HCO3-] + 8 (or pCO2 = 1.25 x [HCO3-]) Metabolic Alkalosis: compensation here is less because CO2 is driving force for respiration. pCO2 = 0.7 x [HCO3-] + 21 (or pCO2 = 0.75 x [HCO3-]) Acutely: [HCO3-] = 0.1 x pCO2 or pH = 0.008 x pCO2 Chronically: [HCO3-] = 0.4 x pCO2 or pH = 0.003 x pCO2 Respiratory Alkalosis: Metabolic compensation will automatically be retention of chloride (i.e., hyperchloremic, usually referred to as loss of bicarb although it is the strong ion difference that matters). If you have an anion gap, then youve automatically got a little bit of an acidosis on top of the compensation (because the compensation should be a NON-gap acidotic process. Acutely: [HCO3-] = 0.2 x pCO2 (or pH = 0.008 x pCO2) Chronically: [HCO3-] = 0.4 x pCO2 (or pH = 0.017 x pCO2) Continue reading >>

Metabolic Vs. Respiratory Acidosis

Metabolic Vs. Respiratory Acidosis

Watch short & fun videos Start Your Free Trial Today Log in or sign up to add this lesson to a Custom Course. Custom Courses are courses that you create from Study.com lessons. Use them just like other courses to track progress, access quizzes and exams, and share content. Organize and share selected lessons with your class. Make planning easier by creating your own custom course. Create a new course from any lesson page or your dashboard. Click "Add to" located below the video player and follow the prompts to name your course and save your lesson. Click on the "Custom Courses" tab, then click "Create course". Next, go to any lesson page and begin adding lessons. Edit your Custom Course directly from your dashboard. Name your Custom Course and add an optional description or learning objective. Create chapters to group lesson within your course. Remove and reorder chapters and lessons at any time. Share your Custom Course or assign lessons and chapters. Share or assign lessons and chapters by clicking the "Teacher" tab on the lesson or chapter page you want to assign. Students' quiz scores and video views will be trackable in your "Teacher" tab. You can share your Custom Course by copying and pasting the course URL. Only Study.com members will be able to access the entire course. We are going to learn about the two different types of acidosis and how they develop. This lesson will explain the differences and similarities that exist between the symptoms and treatments. What comes to mind when you think about acid? You might think about foods that contain acid, such as citrus fruit, or you may think about the battery in your car that contains acid. What probably didn't come to mind is your blood. Our blood is nowhere near as acidic as battery acid or citrus fruit, but the Continue reading >>

Metabolic And Respiratory Acidosis And Alkalosis

Metabolic And Respiratory Acidosis And Alkalosis

There are two main types of pH imbalances in the body: acidosis and alkalosis. An increase in H+ ion levels in the blood causes pH levels to fall resulting in acidosis. A decrease in H+ levels causes pH levels to rise, making the blood more basic, or alkaline. These conditions can be caused by two kinds of disturbances to the buffers that control the body’s pH levels, which alter the acid-base balance. Metabolic and respiratory acidosis and alkalosis are the results of disruptions to the bicarbonate and carbonic acid components of the chemical buffers. Metabolic and respiratory acidosis result when pH levels fall due to an increase in H+ ions or a loss of bases causing the bodily fluids to become slightly acidic. Insufficient bicarbonate levels lower the pH levels of fluids in the digestive tract, resulting in metabolic acidosis. Respiratory acidosis is caused by excessive carbonic acid in the respiratory system, which lowers pH levels through the retention of CO2. Alkalosis is the result of opposite changes to the acid-base balance: excessive bicarbonate levels in the digestive system increases pH as H+ ion concentrations decrease, which causes fluids to become more basic. Insufficient carbonic acid levels are caused by excessive exhalation of CO2, resulting in respiratory alkalosis. Treatment for metabolic and respiratory acidosis and alkalosis varies depending on the underlying cause of the imbalance. Respiratory acidosis caused by hypoventilation can be treated with oxygen therapy and the help of breathing machines to help restore normal oxygen/carbon dioxide exchange, allowing the kidneys time to increase production of bicarbonate and reestablish the acid-base balance of the blood. Respiratory alkalosis caused by hyperventilation can be treated with inhalation of Continue reading >>

Respiratory Alkalosis

Respiratory Alkalosis

Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide.[1][3] This condition is one of the four basic categories of disruption of acid–base homeostasis.[medical citation needed] Signs and symptoms[edit] Signs and symptoms of respiratory alkalosis are as follows:[4] Palpitation Tetany Convulsion Sweating Causes[edit] Respiratory alkalosis may be produced as a result of the following causes: Stress[1] Pulmonary disorder[2] Thermal insult[5] High altitude areas[6] Salicylate poisoning (aspirin overdose) [6] Fever[1] Hyperventilation (due to heart disorder or other, including improper mechanical ventilation)[1][7] Vocal cord paralysis (compensation for loss of vocal volume results in over-breathing/breathlessness).[8] Liver disease[6] Mechanism[edit] Carbonic-acid The mechanism of respiratory alkalosis generally occurs when some stimulus makes a person hyperventilate. The increased breathing produces increased alveolar respiration, expelling CO2 from the circulation. This alters the dynamic chemical equilibrium of carbon dioxide in the circulatory system. Circulating hydrogen ions and bicarbonate are shifted through the carbonic acid (H2CO3) intermediate to make more CO2 via the enzyme carbonic anhydrase according to the following reaction: This causes decreased circulating hydrogen ion concentration, and increased pH (alkalosis).[9][10] Diagnosis[edit] The diagnosis of respiratory alkalosis is done via test that measure the oxygen and carbon dioxide levels (in the blood), chest x-ray and a pulmonary function test of the individual.[1] The Davenport diagram allows clinicians or investigators to outline blood bicarbonate concentr Continue reading >>

Types Of Disturbances

Types Of Disturbances

The different types of acid-base disturbances are differentiated based on: Origin: Respiratory or metabolic Primary or secondary (compensatory) Uncomplicated or mixed: A simple or uncomplicated disturbance is a single or primary acid-base disturbance with or without compensation. A mixed disturbance is more than one primary disturbance (not a primary with an expected compensatory response). Acid-base disturbances have profound effects on the body. Acidemia results in arrythmias, decreased cardiac output, depression, and bone demineralization. Alkalemia results in tetany and convulsions, weakness, polydipsia and polyuria. Thus, the body will immediately respond to changes in pH or H+, which must be kept within strict defined limits. As soon as there is a metabolic or respiratory acid-base disturbance, body buffers immediately soak up the proton (in acidosis) or release protons (alkalosis) to offset the changes in H+ (i.e. the body compensates for the changes in H+). This is very effective so minimal changes in pH occur if the body is keeping up or the acid-base abnormality is mild. However, once buffers are overwhelmed, the pH will change and kick in stronger responses. Remember that the goal of the body is to keep hydrogen (which dictates pH) within strict defined limits. The kidney and lungs are the main organs responsible for maintaining normal acid-base balance. The lungs compensate for a primary metabolic condition and will correct for a primary respiratory disturbance if the disease or condition causing the disturbance is resolved. The kidney is responsible for compensating for a primary respiratory disturbance or correcting for a primary metabolic disturbance. Thus, normal renal function is essential for the body to be able to adequately neutralize acid-base abnor Continue reading >>

Acid-base Disorders - Endocrine And Metabolic Disorders - Merck Manuals Professional Edition

Acid-base Disorders - 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 Vincents Ascension Health, Birmingham Acid-base disorders are pathologic changes in carbon dioxide partial pressure (Pco2) or serum bicarbonate (HCO3) that typically produce abnormal arterial pH values. Acidosis refers to physiologic processes that cause acid accumulation or alkali loss. Alkalosis refers to physiologic processes that cause alkali accumulation or acid loss. Actual changes in pH depend on the degree of physiologic compensation and whether multiple processes are present. Primary acid-base disturbances are defined as metabolic or respiratory based on clinical context and whether the primary change in pH is due to an alteration in serum HCO3 or in Pco2. Metabolic acidosis is serum HCO3< 24 mEq/L. Causes are Metabolic alkalosis is serum HCO3> 24 mEq/L. Causes are Respiratory acidosis is Pco2> 40 mm Hg (hypercapnia). Cause is Decrease in minute ventilation (hypoventilation) Respiratory alkalosis is Pco2< 40 mm Hg (hypocapnia). Cause is Increase in minute ventilation (hyperventilation) Compensatory mechanisms begin to correct the pH (see Table: Primary Changes and Compensations in Simple Acid-Base Disorders ) whenever an acid-base disorder is present. Compensation cannot return pH completely to normal and never overshoots. A simple acid-base disorder is a single acid-base disturbance with its accompanying compensatory response. Mixed acid-base disorders comprise 2 primary disturbances. Compensatory mechanisms for acid-base disturbances cannot return pH completely to normal and never overshoot. Primary Changes and Compensations in Simple Acid-Base Disorders 1.2 mm Hg decrease in Pco2 for every 1 mmol/L decrease in HC Continue reading >>

Metabolic/ Respiratory Acidosis And Alkalosis

Metabolic/ Respiratory Acidosis And Alkalosis

Metabolic/ respiratory acidosis and alkalosis Call me stupid--but I'm having such a time with determining whether a person is in respiratory or metabolic acidosis/alkalosis based on the ABG levels. I know how to determine the acidosis/ alkalosis part---its the difference between metabolic and respiratory that screws me up. If anyone has any suggestions on how to tell the two apart--please share!!!! Ummm, I can't help you without "refreshing." That was last semester for me, and I've already forgotten. You don't use it, you will lose it. Ugggg. I was able to figure it out back then (like, 4 months ago), but I never understood the dynamics between the 2. So, if someone is in Resp Acidosis, what does it mean, what will I objectively see, what will they report, what will I do to help them??? Metabolic Alkalosis Vs. Resp Acidosis - I have no idea how the sx differ. Ya me. Call me stupid--but I'm having such a time with determining whether a person is in respiratory or metabolic acidosis/alkalosis based on the ABG levels. I know how to determine the acidosis/ alkalosis part---its the difference between metabolic and respiratory that screws me up. If anyone has any suggestions on how to tell the two apart--please share!!!! It is hard sometimes, and one can forget easily with out looking at ABGS frequently. co2 might be hco3 in some labs and the 18 or 22 might be 1-2 numbers different. Just write down this down and then circle which ones apply to your ABG results. Then what it is called is the one that caused the acidosis or alkalosis. pco is resp and co2 is metabolic ex your pt abgs are Ph 7.30, pco2, 40 co2 10 This is metabolic acidosis. Call me stupid--but I'm having such a time with determining whether a person is in respiratory or metabolic acidosis/alkalosis based on the Continue reading >>

Respiratory Compensation

Respiratory Compensation

Metabolic Acidosis Respiratory compensation for metabolic disorders is quite fast (within minutes) and reaches maximal values within 24 hours. A decrease in Pco2 of 1 to 1.5 mm Hg should be observed for each mEq/L decrease of in metabolic acidosis.27 A simple rule for deciding whether the fall in Pco2 is appropriate for the degree of metabolic acidosis is that the Pco2 should be equal to the last two digits of the pH. For example, compensation is adequate if the Pco2 decreases to 28 when the pH is 7.28. Alternatively, the Pco2 can be predicted by adding 15 to the observed (down to a value of 12). Although reduction in Pco2 plays an important role in correcting any metabolic acidosis, evidence suggests that it may in some respects be counterproductive because it inhibits renal acid excretion. Fetoplacental Elimination of Metabolic Acid Load Fetal respiratory and renal compensation in response to changes in fetal pH is limited by the level of maturity and the surrounding maternal environment. However, although the placentomaternal unit performs most compensatory functions,3 the fetal kidneys have some, although limited, ability to contribute to the maintenance of fetal acid–base balance. The most frequent cause of fetal metabolic acidosis is fetal hypoxemia owing to abnormalities of uteroplacental function or blood flow (or both). Primary maternal hypoxemia or maternal metabolic acidosis secondary to maternal diabetes mellitus, sepsis, or renal tubular abnormalities is an unusual cause of fetal metabolic acidosis. Pregnant women, at least in late gestation, maintain a somewhat more alkaline plasma environment compared with that of nonpregnant control participants. This pattern of acid–base regulation in pregnant women is present during both resting and after maximal e Continue reading >>

More in ketosis