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Acidosis And Alkalosis

Consequences Of Respiratory Acidosis And Alkalosis - Deranged Physiology

Consequences Of Respiratory Acidosis And Alkalosis - Deranged Physiology

Consequences of Respiratory Acidosis and Alkalosis So, your PaCO2 is, oh say 150mmHg. So what. What could go wrong? Consequences of Respiratory Acid-Base Disorders Increased respiratory stimulus (maximum at 65mmHg) Right shift of the oxyhaemoglobin dissociation curve With a chronically raised PaCO2, a decrease in 2,3-DPG drives the curve back to the left Cerebral vasodilation; headache and increased intracranial pressure CNS depression and a decreased level of consciousness Left shift of oxyhemoglobin dissociation curve Interestingly, none of this has ever made it into the fellowship paper. One might suppose that such fundamental concepts are better interrogated in the primary exam. For those who were for whatever reason exempted from this great barrier, apocryphal pages are available in the section concerned with acid-base disturbances . Specific chapters offer detailed digressions regarding physiological effects of carbon dioxide , buffering in acute respiratory acid-base disturbances and the physiology of carbon dioxide storage and transport . 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 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 >>

Acidosis And Alkalosis

Acidosis And Alkalosis

Find an explanation of your pathology test Acidosis and alkalosis are terms used to describe the abnormal conditions when a patients blood pH does not fall within the healthy range. Measuring the pH of blood is a way of determining how acidic or basic (alkaline) the blood is. Normal blood pH must be maintained within a narrow range of 7.35 - 7.45 to ensure that metabolic processes function properly and the right amount of blood is delivered to the tissues. Many diseases or situations can cause a patients blood pH to fall outside of these limits. In the human body, normal metabolism generates large quantities of acids that must be eliminated to maintain a normal pH balance. Most of the acid is carbonic acid which is produced when carbon dioxide (CO2) combines with water in the body. Lesser quantities of lactic acid, ketoacids and other organic acids are also produced. This balance can be disrupted by a build-up of an acid or a base (alkali) or by an increased loss of an acid or a base (see Figure 1, below). Acidosis occurs when blood pH falls below 7.35 Alkalosis occurs when blood pH rises above 7.45 Both of these conditions act as an alarm to the body; they trigger actions intended to restore the pH balance and return the blood pH to its normal range. The major organs involved in regulating blood pH are the lungs and the kidneys. The lungs flush acid out of the body by exhaling CO2 (carbon dioxide). Within physical limits, the body can raise and lower the rate of breathing to alter the amount of CO2 that is breathed out. This can affect blood pH within seconds or minutes. The kidneys excrete some acids in the urine, and they produce and regulate the retention of HCO3- (bicarbonate), a base that increases the bloods pH or alkalinity. Changes in HCO3- concentration occur Continue reading >>

Ketoacid Production In Acute Respiratory And Metabolic Acidosis And Alkalosis In Rats.

Ketoacid Production In Acute Respiratory And Metabolic Acidosis And Alkalosis In Rats.

Ketoacid production in acute respiratory and metabolic acidosis and alkalosis in rats. Department of Medicine, University of Vermont College of Medicine, Burlington 05405. Am J Physiol. 1989 Mar;256(3 Pt 2):F437-45. Metabolic acidosis inhibits and alkalosis enhances ketoacid production in ketotic humans and animals. To compare these effects with those of superimposed respiratory acid-base disturbances, ketone output was evaluated in awake ketotic rats during metabolic (intravenous infusions of HCl or NaHCO3) or respiratory (hyper or hypocapnia) disorders. With decreases in blood pH of 0.1-0.2 units over 3 h, blood ketone concentrations significantly decreased an average of 1.9 mM (metabolic) and 1.1 mM (respiratory) and urinary ketone excretion rates significantly decreased by 1.3 mumol/min (metabolic). With increases in systemic pH, blood ketone concentrations and urinary ketone excretion rates were significantly increased. Changes in blood pH correlated with changes in urinary ketone excretion rates in both metabolic (r = 0.87) and respiratory (r = 0.67) acid-base disturbances. The alterations occurred promptly and were rapidly reversible. These findings indicate that modest changes in systemic pH from metabolic or respiratory acid-base disturbances modify net ketoacid production in ketotic rats, confirm pH control of endogenous acid output as an acid-base regulator, and show that systemic pH, not bicarbonate concentration, mediates the process. Continue reading >>

Acidosis/alkalosis:

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 >>

Csf Bicarbonate Regulation In Respiratory Acidosis And Alkalosis.

Csf Bicarbonate Regulation In Respiratory Acidosis And Alkalosis.

CSF bicarbonate regulation in respiratory acidosis and alkalosis. CSF bicarbonate regulation was studied in respiratory acidosis and alkalosis of 4h duration in antsthetized dogs. PCO2, pH, HCO3, ammonia, and lactate in CSF and arterial and safittal sinus bloof were measured when equal volumes of saline or acetazolamide (8 mg) were injected into lateral cerebral ventricles. The brain CO2 dissociation curve was determined at the end of all experiments. CSF and arterial bicarbonate increased 11.8 and 5.9 meg/l, respectively, in acidosis. Acetazolamide limited the rise in CSF bicarbonate to 4.2 meg/l, and prevented the CSF bicarbonate increase associated with hyperammonemia. During alkalosis CSF bicarbonate fell 6.5 meg/l and CSF lactate increased almost 2 meg/l while arterial bicarbonate fell 5.7 meg/l and lactate remained unchanged. Thus plasma bicarbonate changes account for some of the CSF unchanged. Thus plasma bicarbonate changes account for some of the CSF bicarbonate alterations in respiratory acid-base-disturbances. In acidosis additional CSF bicarbonate is formed by the choroid plexus and glial cells on the inner and outer surfaces of the brain--a reaction catalyzed by the locally present carbonic anhydrase. In alkalosis the greater fall in CSF bicarbonate than blood is due to selective brain and CSF lactic acidosis. Continue reading >>

Acidosis

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 >>

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 >>

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 >>

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

Acidosis

When your body fluids contain too much acid, it’s known as acidosis. Acidosis occurs when your kidneys and lungs can’t keep your body’s pH in balance. Many of the body’s processes produce acid. Your lungs and kidneys can usually compensate for slight pH imbalances, but problems with these organs can lead to excess acid accumulating in your body. The acidity of your blood is measured by determining its pH. A lower pH means that your blood is more acidic, while a higher pH means that your blood is more basic. The pH of your blood should be around 7.4. According to the American Association for Clinical Chemistry (AACC), acidosis is characterized by a pH of 7.35 or lower. Alkalosis is characterized by a pH level of 7.45 or higher. While seemingly slight, these numerical differences can be serious. Acidosis can lead to numerous health issues, and it can even be life-threatening. There are two types of acidosis, each with various causes. The type of acidosis is categorized as either respiratory acidosis or metabolic acidosis, depending on the primary cause of your acidosis. Respiratory acidosis Respiratory acidosis occurs when too much CO2 builds up in the body. Normally, the lungs remove CO2 while you breathe. However, sometimes your body can’t get rid of enough CO2. This may happen due to: chronic airway conditions, like asthma injury to the chest obesity, which can make breathing difficult sedative misuse deformed chest structure Metabolic acidosis Metabolic acidosis starts in the kidneys instead of the lungs. It occurs when they can’t eliminate enough acid or when they get rid of too much base. There are three major forms of metabolic acidosis: Diabetic acidosis occurs in people with diabetes that’s poorly controlled. If your body lacks enough insulin, keton Continue reading >>

Acidosis And Alkalosis

Acidosis And Alkalosis

Acidosis is a condition caused by removal of bicarbonateor an increase in carbonic acid in blood. The net result is a disturbancein the carbonic acid-bicarbonate equilibrium to produce an excess [H+] inblood causing lower blood pH. Metabolic acidosis can occur as a result ofdiabetes, starvation and high fat diet all of which leads to the productionof ketones in the blood. Ketones bind & remove bicarbonate. If not controlled it can be fatal [see ketoacidosis and diabetesin the further reading folder]. Alkalosis occurs when [bicarbonate] increases forcing theequilibrium to remove protons from blood causing blood pH to rise. So pHbecomes alkaline leading to vomiting, nausea, headache. Temporary metabolic alkalosis occurs when there is an intakeof sodium bicarbonate e.g. if large amounts are taken for acid in the stomach.Respiratory alkalosis can be induced by hyperventilation i.e. excessiveexhalation of carbon dioxide from lungs too quickly causing too great aloss of H+ from the large reservoir. Anything that causes sustained rapidbreathing can induce temporary alkalosis, e.g. hysteria (pop concert), hotbaths, training. Athletes such as marathon runners learn to control breathingso as to minimise alkalosis. Sprinters and swimmers who understand biochemistrytune their bodies for maximum effort. Strenuous bursts of muscle activityproduce high levels of lactic acid as glucose is broken down for energy.Lactic acid can lower the pH of blood and cause muscle cramp/fatigue. To counteract this, athletes will prepare by rapid deepbreathing for 30-40 seconds before the race to hyperventilate and introducetemporary alkaline conditions that will help to neutralise the acidity arisingfrom lactic acid. For more detail on this topicsee the text book page 57 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 >>

Acid-base Disturbances In Children, Acidosis, Alkalosis

Acid-base Disturbances In Children, Acidosis, Alkalosis

Acid-base disturbances in children, Acidosis, Alkalosis Acid-base disturbances in children, Acidosis, Alkalosis The pH of the blood is controlled via three systems: chemical buffering, respiratory function, and renal function. Acidosis means a clinical disturbance in which there is an increase in plasma acidity, whether due to increased production by the tissues, loss of buffering ability or decreased clearance by the kidneys. A multitude of problems, congenital and acquired, can result in metabolic acidosis. The hallmark of a metabolic acidosis is a low serum HCO3 level. Metabolic alkalosis means the patient has an elevated HCO3, most typically seen with administration of loop diuretics. A respiratory acidosis means an increase in the partial pressure of carbon dioxide in the blood (PaCO2) due to inadequate respiration. Respiratory alkalosis typically occurs in response to a metabolic stimulus, such as hyperammonemia (seen in urea cycle defects) or diabetic ketoacidosis (DKA). Metabolic and respiratory mechanisms affect the acid-base state. The relationship between the pH and PaCO2 is dependent upon the plasma bicarbonate-plasma carbonic acid pool. To estimate the effect of pH change, for every 10 mmHg PaCO2, the pH will change by approximately 0.08; for example, if the PaCO2 rises to 50 from a normal 40 mmHg, then the expected pH will be approximately 7.32, or decreased by 0.08. Comparison of the base excess with the reference range assists in determining whether an acid-base disturbance is caused by a respiratory, metabolic or mixed metabolic/respiratory problem. While CO2 defines the respiratory component of acid-base balance, base excess defines the metabolic component. To generalize, a metabolic acidosis will have a low serum HCO3 and a respiratory acidosis will Continue reading >>

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