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Metabolic And Respiratory Acidosis And Alkalosis

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 >>

Acidosis

Acidosis

The kidneys and lungs maintain the balance (proper pH level) of chemicals called acids and bases in the body. Acidosis occurs when acid builds up or when bicarbonate (a base) is lost. Acidosis is classified as either respiratory or metabolic acidosis. Respiratory acidosis develops when there is too much carbon dioxide (an acid) in the body. This type of acidosis is usually caused when the body is unable to remove enough carbon dioxide through breathing. Other names for respiratory acidosis are hypercapnic acidosis and carbon dioxide acidosis. Causes of respiratory acidosis include: Chest deformities, such as kyphosis Chest injuries Chest muscle weakness Chronic lung disease Overuse of sedative drugs Metabolic acidosis develops when too much acid is produced in the body. It can also occur when the kidneys cannot remove enough acid from the body. There are several types of metabolic acidosis: Diabetic acidosis (also called diabetic ketoacidosis and DKA) develops when substances called ketone bodies (which are acidic) build up during uncontrolled diabetes. Hyperchloremic acidosis is caused by the loss of too much sodium bicarbonate from the body, which can happen with severe diarrhea. Poisoning by aspirin, ethylene glycol (found in antifreeze), or methanol Lactic acidosis is a buildup of lactic acid. Lactic acid is mainly produced in muscle cells and red blood cells. It forms when the body breaks down carbohydrates to use for energy when oxygen levels are low. This can be caused by: Cancer Drinking too much alcohol Exercising vigorously for a very long time Liver failure Low blood sugar (hypoglycemia) Medications, such as salicylates MELAS (a very rare genetic mitochondrial disorder that affects energy production) Prolonged lack of oxygen from shock, heart failure, or seve 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 >>

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 >>

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 >>

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 >>

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 >>

Abg Interpretation

Abg Interpretation

Arterial blood gas (ABG) interpretation is something many medical students find difficult to grasp (we’ve been there). We’ve created this guide, which aims to provide a structured approach to ABG interpretation whilst also increasing your understanding of each results relevance. The real value of an ABG comes from its ability to provide a near immediate reflection of the physiology of your patient, allowing you to recognise and treat pathology more rapidly. To see how to perform an arterial blood gas check out our guide here. If you want to put your ABG interpretation skills to the test, check out our ABG quiz here. Normal ranges pH: 7.35 – 7.45 PaCO2: 4.7-6.0 kPa PaO2: 11-13 kPa HCO3-: 22-26 mEg/L Base excess: -2 to +2 mmol/L Patient’s clinical condition Before getting stuck into the details of the analysis, it’s important to look at the patient’s current clinical status, as this provides essential context to the ABG result. Below are a few examples to demonstrate how important context is when interpreting an ABG. A normal PaO2 in a patient on high flow oxygen – this is abnormal as you would expect the patient to have a PaO2 well above the normal range with this level of oxygen therapy A normal PaCO2 in a hypoxic asthmatic patient – a sign they are tiring and need ITU intervention A very low PaO2 in a patient who looks completely well, is not short of breath and has normal O2 saturations – likely a venous sample Oxygenation (PaO2) Your first question when looking at the ABG should be “Is this patient hypoxic?” (because this will kill them long before anything else does). PaO2 should be >10 kPa on air in a healthy patient If the patient is receiving oxygen therapy their PaO2 should be approximately 10kPa less than the % inspired concentration / FiO Continue reading >>

9.3 Bedside Rules For Assessment Of Compensation

9.3 Bedside Rules For Assessment Of Compensation

The method of assessing acid-base disorders discussed here uses a set of six rules which are used primarily to assess the magnitude of the patients compensatory response. These rules are now widely known and are soundly based experimentally. These rules are used at Step 4 of the method of Systematic Acid-Base Diagnosis outlined in Section 9.2.- (You should read section 9.1 & 9.2 before this section.) These rules are called 'bedside rules' because that can be used at the patient's bedside to assist in the assessment of the acid-base results. The rules should preferably be committed to memory - with practice this is not difficult. A full assessment of blood-gas results must be based on a clinical knowledge of the individual patient from whom they were obtained and an understanding of the pathophysiology of the clinical conditions underlying the acid-base disorder. Do not interpret the blood-gas results as an intellectual exercise in itself. It is one part of the overall process of assessing and managing the patient. A set of blood-gas and electrolyte results should NOT be interpreted without these initial clinical details. They cannot be understood fully without knowledge of the condition being diagnosed. Diagnosing a metabolic acidosis, for example, is by itself, often of little clinical use. What is really required is a more specific diagnosis of the cause of the metabolic acidosis (eg diabetic ketoacidosis, acute renal failure, lactic acidosis) and to initiate appropriate management. The acid-base analysis must be interpreted and managed in the context of the overall clinical picture. The snapshot problem: Are the results 'current'? Remember also that a set of blood gas results provides a snapshot at a particular point in time and the situation may have changed since 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 >>

Acid-base Balance

Acid-base Balance

Your blood needs the right balance of acidic and basic (alkaline) compounds to function properly. This is called the acid-base balance. Your kidneys and lungs work to maintain the acid-base balance. Even slight variations from the normal range can have significant effects on your vital organs. Acid and alkaline levels are measured on a pH scale. An increase in acidity causes pH levels to fall. An increase in alkaline causes pH levels to rise. When the levels of acid in your blood are too high, it’s called acidosis. When your blood is too alkaline, it is called alkalosis. Respiratory acidosis and alkalosis are due to a problem with the lungs. Metabolic acidosis and alkalosis are due to a problem with the kidneys. Each of these conditions is caused by an underlying disease or disorder. Treatment depends on the cause. When you breathe, your lungs remove excess carbon dioxide from your body. When they cannot do so, your blood and other fluids become too acidic. Symptoms of respiratory acidosis Symptoms may include fatigue, shortness of breath, and confusion. Causes of respiratory acidosis There are several different causes of respiratory acidosis including: chest deformities or injuries chronic lung and airway diseases overuse of sedatives obesity Types of respiratory acidosis There are no noticeable symptoms of chronic respiratory acidosis. This is due to the fact that your blood slowly becomes acidic and your kidneys adjust to compensate, returning your blood to a normal pH balance. Acute respiratory acidosis comes on suddenly, leaving the kidneys no time to adjust. Those with chronic respiratory acidosis may experience acute respiratory acidosis due to another illness that causes the condition to worsen. Diagnosis of respiratory acidosis A complete physical examination Continue reading >>

Metabolic Alkalosis: Practice Essentials, Pathophysiology, Etiology

Metabolic Alkalosis: Practice Essentials, Pathophysiology, Etiology

Author: Christie P Thomas, MBBS, FRCP, FASN, FAHA; Chief Editor: Vecihi Batuman, MD, FASN more... 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 al Continue reading >>

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 >>

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 >>

Acidosis And Alkalosis | Harrison's Principles Of Internal Medicine, 19e | Accessmedicine | Mcgraw-hill Medical

Acidosis And Alkalosis | Harrison's Principles Of Internal Medicine, 19e | Accessmedicine | Mcgraw-hill Medical

Systemic arterial pH is maintained between 7.35 and 7.45 by extracellular and intracellular chemical buffering together with respiratory and renal regulatory mechanisms. The control of arterial CO2 tension (Paco2) by the central nervous system (CNS) and respiratory system and the control of plasma bicarbonate by the kidneys stabilize the arterial pH by excretion or retention of acid or alkali. The metabolic and respiratory components that regulate systemic pH are described by the Henderson-Hasselbalch equation: Under most circumstances, CO2 production and excretion are matched, and the usual steady-state Paco2 is maintained at 40 mmHg. Underexcretion of CO2 produces hypercapnia, and overexcretion causes hypocapnia. Nevertheless, production and excretion are again matched at a new steady-state Paco2. Therefore, the Paco2 is regulated primarily by neural respiratory factors and is not subject to regulation by the rate of CO2 production. Hypercapnia is usually the result of hypoventilation rather than of increased CO2 production. Increases or decreases in Paco2 represent derangements of neural respiratory control or are due to compensatory changes in response to a primary alteration in the plasma [HCO3]. DIAGNOSIS OF GENERAL TYPES OF DISTURBANCES The most common clinical disturbances are simple acid-base disorders; i.e., metabolic acidosis or alkalosis or respiratory acidosis or alkalosis. Primary respiratory disturbances (primary changes in Paco2) invoke compensatory metabolic responses (secondary changes in [HCO3]), and primary metabolic disturbances elicit predictable compensatory respiratory responses (secondary changes in Paco2). Physiologic compensation can be predicted from the relationships displayed in Table 66-1 . In general, with one exception, compensatory res Continue reading >>

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