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 >>
Alkalosis
Your blood is made up of acids and bases. The amount of acids and bases in your blood can be measured on a pH scale. It’s important to maintain the correct balance between acids and bases. Even a slight change can cause health problems. Normally, your blood should have a slightly higher amount of bases than acids. Alkalosis occurs when your body has too many bases. It can occur due to decreased blood levels of carbon dioxide, which is an acid. It can also occur due to increased blood levels of bicarbonate, which is a base. This condition may also be related to other underlying health issues such as low potassium, or hypokalemia. The earlier it’s detected and treated, the better the outcome is. Acid-base balance » There are five main types of alkalosis. Respiratory alkalosis Respiratory alkalosis occurs when there isn’t enough carbon dioxide in your bloodstream. It’s often caused by: hyperventilation, which commonly occurs with anxiety high fever lack of oxygen salicylate poisoning being in high altitudes Metabolic alkalosis Metabolic alkalosis develops when your body loses too much acid or gains too much base. This can be attributed to: excess vomiting, which causes electrolyte loss overuse of diuretics a large loss of potassium or sodium in a short amount of time antacids accidental ingestion of bicarbonate, which can be found in baking soda laxatives alcohol abuse Hypochloremic alkalosis Hypochloremic alkalosis occurs when there’s a significant decline of chloride in your body. This can be due to prolonged vomiting or sweating. Chloride is an important chemical needed to maintain balance in bodily fluids, and it’s an essential part of your body’s digestive fluids. Hypokalemic alkalosis Hypokalemic alkalosis occurs when your body lacks the normal amount Continue reading >>
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 >>
Alkalosis
The kidneys and lungs maintain the proper balance (proper pH level) of chemicals called acids and bases in the body. Decreased carbon dioxide (an acid) level or increased bicarbonate (a base) level makes the body too alkaline, a condition called alkalosis. There are different types of alkalosis. These are described below. Respiratory alkalosis is caused by a low carbon dioxide level in the blood. This can be due to: Fever Being at a high altitude Lack of oxygen Liver disease Metabolic alkalosis is caused by too much bicarbonate in the blood. It can also occur due to certain kidney diseases. Hypochloremic alkalosis is caused by an extreme lack or loss of chloride, such as from prolonged vomiting. Hypokalemic alkalosis is caused by the kidneys' response to an extreme lack or loss of potassium. This can occur from taking certain water pills (diuretics). Compensated alkalosis occurs when the body returns the acid-base balance to normal in cases of alkalosis, but bicarbonate and carbon dioxide levels remain abnormal. Continue reading >>
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 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 >>
Acidosis Vs. Alkalosis
In this lesson, we're going to learn about acidosis and alkalosis. We'll take a look at the causes, signs, and symptoms that are associated with each condition. Balanced Blood We are constantly having to find balance in our lives. From balancing work and play time to saving and spending money, sleep and awake time. Well, ideally at least. We do this because we know that we function best when we're balanced. There are many similar balances that are going on inside of our bodies. An important balance that must be maintained to allow us to function properly is the balance between acids and bases in our bodies. When these are balanced, the acids pair up with the bases, and our blood is close to neutral. If too much acid is in the blood, then we experience acidosis. If too much base is in the blood, we experience alkalosis. Acidosis and alkalosis are caused by different conditions in our bodies, and they can cause different problems to occur. Acidosis Acidosis results from the build-up of acids in the blood or from the loss of base in the blood. Acids are put into our bloodstream through two systems in the body: the digestive system and the respiratory system. Acidosis that occurs from the digestive system is referred to as metabolic acidosis. In this instance, acids accumulate in the blood due to consumption of acidic foods or foods that are broken down into acids, excess acids being produced during metabolism, kidneys not properly removing acid from the bloodstream during filtration, or production of acid by the body due to other medical conditions, such as diabetes. The other possible way to develop acidosis is by the malfunctioning of the respiratory system, which we refer to as respiratory acidosis. This can happen if breathing is extremely slow or shallow, the lungs do Continue reading >>
Metabolic Vs Respiratory Acidosis/alkalosis- When To Tell What's Going On First?
Don't miss your chance to win free admissions prep materials! Click here to see a list of raffles . metabolic vs respiratory acidosis/alkalosis- when to tell what's going on first? So I was doing a practice passage from Kaplan and came across this passage discussing metabolic vs respiratory alkalosis/acidosis. I'm having a lot of trouble answering the questions requiring you to figure out how to determine which one occurs first based on the graph that came with the passage. You can eliminate A and C because point C is in an alkalotic state (is that even a word? Lol.) Point A is physiological pH, PCO2 and PHCO3. Look at the PCO2 levels at point C. This patient is in a state of hyperoxemia (too little CO2 in the body or too much O2 [aka hyperventilation]). The [HCO3-] is also at a basal rate, meaning this isn't a metabolic disorder, eliminating B. I am not sure whether I am looking at it right, but just using my own logic. Eliminate B, because in metabolic alkalosis the initial change is an increase in bicarb , and on the graph it clearly decreases. And it's D because from A to C, you have a decrease in CO2 which is an initial change plus you have a decrease in bicarb because it's a compensatory response. Thanks guys! so just to double check I'm understanding right.. for this question, if it was metabolic acidosis followed by compensatory respiratory alkalosis, we would see a decrease in HCO3- concentration and an increase in CO2? Also, does anyone understand why CO2 is considered an acid in the buffer system? Thanks guys! so just to double check I'm understanding right.. View attachment 195282 for this question, if it was metabolic acidosis followed by compensatory respiratory alkalosis, we would see a decrease in HCO3- concentration and an increase in CO2? Also, does a Continue reading >>
Metabolic Alkalosis And Metabolic Acidosis Nclex Quiz | Acid-base Imbalances Quiz
This NCLEX quiz will test your ability to differentiate between metabolic acidosis vs metabolic alkalosis. You will be required to know the causes, signs and symptoms, and how to interpret blood gas values in this quiz. As a nursing student, it is crucial you know the basics about acid-base imbalances. Below are common test questions you may encounter on your nursing lecture exam or NCLEX licensing exam. Also, don’t forget to take our free Arterial Blood Gas (ABGs) Quiz. After you are done taking the quiz and click submit, the page will refresh and you will need to scroll down to see what you got right and wrong. In addition, below this quiz is a layout of the quiz with an answer key (if you wanted to print off the quiz..just copy and paste it). Don’t forget to share this quiz with your friends! Please do not re-post on other websites, however. Metabolic Acidosis and Metabolic Alkalosis Quiz NCLEX Diabetic ketoacidosis, aspirin toxicity, and renal failure are examples of the causes of ___________________. A. High anion gap metabolic acidosis B. Normal anion gap metabolic acidosis C. Low anion gap metabolic acidosis D. Normal anion gap respiratory acidosis A patient has the following arterial blood gases: PaCO2 33, HCO3 15, pH 7.23. Which of the following conditions are presenting? A. Metabolic alkalosis partially compensated B. Metabolic acidosis partially compensated C. Respiratory alkalosis not compensated D. Metabolic acidosis fully compensated A patient is in high anion gap metabolic acidosis due to diabetic ketoacidosis. Which of the following signs and symptoms would you expect to see in this patient? A. Kussmaul’s respirations B. Glucose 110 C. Hypoventilation D. Neuro-excitability A patient reports taking Diamox and has been reporting confusion, fatigue, a Continue reading >>
Acidosis
For acidosis referring to acidity of the urine, see renal tubular acidosis. "Acidemia" redirects here. It is not to be confused with Academia. Acidosis is a process causing increased acidity in the blood and other body tissues (i.e., an increased hydrogen ion concentration). If not further qualified, it usually refers to acidity of the blood plasma. The term acidemia describes the state of low blood pH, while acidosis is used to describe the processes leading to these states. Nevertheless, the terms are sometimes used interchangeably. The distinction may be relevant where a patient has factors causing both acidosis and alkalosis, wherein the relative severity of both determines whether the result is a high, low, or normal pH. Acidosis is said to occur when arterial pH falls below 7.35 (except in the fetus – see below), while its counterpart (alkalosis) occurs at a pH over 7.45. Arterial blood gas analysis and other tests are required to separate the main causes. The rate of cellular metabolic activity affects and, at the same time, is affected by the pH of the body fluids. In mammals, the normal pH of arterial blood lies between 7.35 and 7.50 depending on the species (e.g., healthy human-arterial blood pH varies between 7.35 and 7.45). Blood pH values compatible with life in mammals are limited to a pH range between 6.8 and 7.8. Changes in the pH of arterial blood (and therefore the extracellular fluid) outside this range result in irreversible cell damage.[1] Signs and symptoms[edit] General symptoms of acidosis.[2] These usually accompany symptoms of another primary defect (respiratory or metabolic). Nervous system involvement may be seen with acidosis and occurs more often with respiratory acidosis than with metabolic acidosis. Signs and symptoms that may be seen i Continue reading >>
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 >>
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 >>
Acidosis/alkalosis:
Bases: Have a higher affinity for protons than water and easily acquire protons in aqueous solution. charged (+1) when protonated (Acids uncharged) uncharged when de-protonated (Acids -1 charge) Most common biological weak base is the amino group, -NH2 Despite the differences between acids and bases the pKa concept can be used to quantitate the relative strength of amino groups. Notice: pKa values for carboxylic acid are less than < 7, pka values for amino groups are >7 (usually 9-11) i.e. a simple biologically important 10 amine, ethanolamine, pKa = 9.5 or choline, a quaternary (40) amine, pKa = 13.9 Choline is a good compound for systems in which a permanent positive charge is desirable, i.e. membranes (hydrophilic head groups) Phosphatidylcholine (lecithin) a key amphiphilic compound in biological membranes Buffering: At or near their pKa both weak acids and weak bases will resist changes in pH, thus acting as buffers Buffering is very important in biological systems, for rapid pH changes have disastrous consequences. The buffering capacity of ethanolamine and acetic acid occur well outside of the pH range normally seen in human blood (pH 7.35-7.45). Thus, other ionizable compounds must serve this function in biological fluids. The most important single buffer in human is the bicarbonate ion -CO2 is added to the system at varying rates by metabolic processes -rate of formation of H2CO3 from CO2 and H2O is slow, so is enhanced by the enzyme, carbonic anhydrase, found in red blood cells (RBC) -CO2 is expired by the lungs at varying rates (respiration) -levels of HCO3- can be adjusted by the kidney via excretion CO2Production: -normally balanced by CO2 expired from the lungs However, certain medical conditions can throw the equation out of balance... Respiratory Acidosi Continue reading >>
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 >>
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 >>
