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How Does The Respiratory System Help To Compensate For Metabolic Acidosis?

Metabolic Alkalosis

Metabolic Alkalosis

Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35–7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations. Terminology[edit] Alkalosis refers to a process by which the pH is increased. Alkalemia refers to a pH which is higher than normal, specifically in the blood. Causes[edit] The causes of metabolic alkalosis can be divided into two categories, depending upon urine chloride levels.[1] Chloride-responsive (Urine chloride < 10 mEq/L)[edit] Loss of hydrogen ions - Most often occurs via two mechanisms, either vomiting or via the kidney. Vomiting results in the loss of hydrochloric acid (hydrogen and chloride ions) with the stomach contents. In the hospital setting this can commonly occur from nasogastric suction tubes. Severe vomiting also causes loss of potassium (hypokalaemia) and sodium (hyponatremia). The kidneys compensate for these losses by retaining sodium in the collecting ducts at the expense of hydrogen ions (sparing sodium/potassium pumps to prevent further loss of potassium), leading to metabolic alkalosis.[2] Congenital chloride diarrhea - rare for being a diarrhea that causes alkalosis instead of acidosis.[3] Contraction alkalosis - This results from a loss of water in the extracellular space, such as from dehydration. Decreased extracellular volume triggers the renin-angiotensin-aldosterone system, and aldosterone subsequently stimulates reabsorption of sodium (and thus water) within the nephron of the kidney. However, a second action of aldosterone is to stimulate renal excretion of hydrogen ions (while retaining bicarbonate), and it is this loss of hydrogen ions that raises Continue reading >>

Respiratory Compensation

Respiratory Compensation

Publisher Summary This chapter elaborates the bicarbonate buffer system and respiratory compensation. The plasma pH is defined as –log [H+], and when [H+] increases, the pH decreases. The condition of high plasma pH is called alkalosis and low plasma pH is acidosis. The body has three lines of defense against departures from normal plasma pH—the chemical buffers, the respiratory system, and the renal system. The chemical buffers passively resist changes in pH by absorbing excess H+ when pH falls or by releasing H+ ions when pH rises. Chemical buffers include proteins, phosphate, and bicarbonate buffers. All of these equilibrate with a single [H+], and so the buffer systems are linked. This is the isohydric principle, and because of this link, adjustment of the bicarbonate buffer system controls all buffer systems. The bicarbonate buffer system has two components that include plasma [CO2] and [HCO3−]. The respiratory system controls plasma pH by adjusting the [CO2]. The equilibrium between dissolved CO2 and H2CO3 is accelerated by carbonic anhydrase. Respiratory alkalosis results from hyperventilation as the primary disturbance. Hyperventilation also forms the respiratory compensation of metabolic acidosis. It is found that complete compensation of pH disturbances requires the kidney to change plasma [HCO3−]. Increased Carbon Dioxide: Respiratory Acidosis Respiratory acidosis may result from a primary respiratory disorder or it can be a physiologic respiratory compensation for a metabolic alkalosis. An increase in HCO3− of 1 mEq/L should result in an increase in PCO2 of 0.7 mm Hg in both dogs and cats.1,3 Pathologic respiratory acidosis results from an imbalance in CO2 production via metabolism and excretion via the lung. Common causes include large airway obst 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 >>

Respiratory Acidosis

Respiratory Acidosis

LABORATORY TESTS The following lab tests can be used to interpret and explain acidosis and alkalosis conditions. All are measured on blood samples. 1. pH: This measures hydrogen ions - Normal pH = 7.35-7.45 2. pCO2= Partial Pressure of Carbon Dioxide: Although this is a pressure measurement, it relates to the concentration of GASEOUS CO2 in the blood. A high pCO2 may indicate acidosis. A low pCO2 may indicate alkalosis. 3. HCO3- = Bicarbonate: This measures the concentration of HCO3- ion only. High values may indicate alkalosis since bicarbonate is a base. Low values may indicate acidosis. 4. CO2 = Carbon Dioxide Content: This is a measure of ALL CO2 liberated on adding acid to blood plasma. This measure both carbon dioxide dissolved and bicarbonate ions and is an older test. Do not confuse with pCO2 Typically, dissolved carbon dioxide = l.2-2.0 mmoles/L and HCO3- = 22-28 mmoles/L Therefore, although it is listed as CO2 content, the lab test really reflects HCO3- concentration. Respiratory Acidosis .ABNORMAL pH IN THE BODY: ACIDOSIS AND ALKALOSIS: INTRODUCTION: Normal blood pH is maintained between 7.35 and 7.45 by the regulatory systems. The lungs regulate the amount of carbon dioxide in the blood and the kidneys regulate the bicarbonate. When the pH decreases to below 7.35 an acidosis condition is present. Acidosis means that the hydrogen ions are increased and that pH and bicarbonate ions are decreased. A greater number of hydrogen ions are present in the blood than can be absorbed by the buffer systems. Alkalosis results when the pH is above 7.45. This condition results when the buffer base (bicarbonate ions) is greater than normal and the concentration of hydrogen ions are decreased. Both acidosis and alkalosis can be of two different types: respiratory and metabol Continue reading >>

Respiratory Acidosis

Respiratory Acidosis

Practice Essentials Respiratory acidosis is an acid-base balance disturbance due to alveolar hypoventilation. Production of carbon dioxide occurs rapidly and failure of ventilation promptly increases the partial pressure of arterial carbon dioxide (PaCO2). [1] The normal reference range for PaCO2 is 35-45 mm Hg. Alveolar hypoventilation leads to an increased PaCO2 (ie, hypercapnia). The increase in PaCO2, in turn, decreases the bicarbonate (HCO3–)/PaCO2 ratio, thereby decreasing the pH. Hypercapnia and respiratory acidosis ensue when impairment in ventilation occurs and the removal of carbon dioxide by the respiratory system is less than the production of carbon dioxide in the tissues. Lung diseases that cause abnormalities in alveolar gas exchange do not typically result in alveolar hypoventilation. Often these diseases stimulate ventilation and hypocapnia due to reflex receptors and hypoxia. Hypercapnia typically occurs late in the disease process with severe pulmonary disease or when respiratory muscles fatigue. (See also Pediatric Respiratory Acidosis, Metabolic Acidosis, and Pediatric Metabolic Acidosis.) Acute vs chronic respiratory acidosis Respiratory acidosis can be acute or chronic. In acute respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range (ie, >45 mm Hg) with an accompanying acidemia (ie, pH < 7.35). In chronic respiratory acidosis, the PaCO2 is elevated above the upper limit of the reference range, with a normal or near-normal pH secondary to renal compensation and an elevated serum bicarbonate levels (ie, >30 mEq/L). Acute respiratory acidosis is present when an abrupt failure of ventilation occurs. This failure in ventilation may result from depression of the central respiratory center by one or another of the foll Continue reading >>

Overview Of Acid-base Balance

Overview Of Acid-base Balance

An important property of blood is its degree of acidity or alkalinity. The acidity or alkalinity of any solution, including blood, is indicated on the pH scale. A doctor evaluates a person's acid-base balance by measuring the pH and levels of carbon dioxide (an acid) and bicarbonate (a base) in the blood. Blood acidity increases when the Level of acidic compounds in the body rises (through increased intake or production, or decreased elimination) Level of basic (alkaline) compounds in the body falls (through decreased intake or production, or increased elimination) Blood alkalinity increases when the level of acid in the body decreases or when the level of base increases. Control of Acid-Base Balance The body's balance between acidity and alkalinity is referred to as acid-base balance. The blood's acid-base balance is precisely controlled because even a minor deviation from the normal range can severely affect many organs. The body uses different mechanisms to control the blood's acid-base balance. These mechanisms involve the Role of the lungs One mechanism the body uses to control blood pH involves the release of carbon dioxide from the lungs. Carbon dioxide, which is mildly acidic, is a waste product of the processing (metabolism) of oxygen (which all cells need) and, as such, is constantly produced by cells. As with all waste products, carbon dioxide gets excreted into the blood. The blood carries carbon dioxide to the lungs, where it is exhaled. As carbon dioxide accumulates in the blood, the pH of the blood decreases (acidity increases). The brain regulates the amount of carbon dioxide that is exhaled by controlling the speed and depth of breathing (ventilation). The amount of carbon dioxide exhaled, and consequently the pH of the blood, increases as breathing bec Continue reading >>

Metabolic Alkalosis: Respiratory Compensation

Metabolic Alkalosis: Respiratory Compensation

Definition Metabolic alkalosis is a very common primary acid–base disturbance associated with increased plasma HCO3. Increased extracellular HCO3 is due to net loss of H+ and/or addition of HCO3. The most common cause of metabolic alkalosis is gastrointestinal acid loss because of vomiting or nasogastric suctioning; the resulting hypovolemia leads to secretion of renin and aldosterone and enhanced absorption of HCO3.Diuretics are another common cause of metabolic alkalosis. Thiazides (e.g., hydrochlorothiazide) and loop diuretics (e.g., furosemide) induce a net loss of chloride and free water, without altering bicarbonate excretion, and can cause a volume “contraction” alkalosis. When metabolic alkalosis is persistent, it usually reflects an inability of the kidney to excrete HCO3. Rare inherited renal causes of metabolic alkalosis exist (e.g., Bartter syndrome). A typical respiratory response to all types of metabolic alkalosis is hypoventilation leading to a pH correction towards normal. Increases in arterial blood pH depress respiratory centers. The resulting alveolar hypoventilation tends to elevate PaCO2 and restore arterial pH toward normal. The pulmonary response to metabolic alkalosis is generally less predictable than the response to metabolic acidosis. Hypoxemia, as a result of progressive hypoventilation, eventually activates oxygen-sensitive chemoreceptors; the latter stimulates ventilation and limits the compensatory pulmonary response. Consequently, PaCO2 usually does not rise above 55 mm Hg in response to metabolic alkalosis. As a general rule, PaCO2 can be expected to increase 0.25–1 mm Hg for each 1 mEq/L increase in [HCO3–]. Subspecialty Keyword history See Also: Sources PubMed 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 >>

How Does The Renal System Compensate For Conditions Of Respiratory Alkalosis?

How Does The Renal System Compensate For Conditions Of Respiratory Alkalosis?

In order to function normally, your body needs a blood pH of between 7.35 and 7.45. Alkalosis is when you have too much base in your blood, causing your blood pH to rise above 7.45. The lungs and the kidneys are the two main organs involved in maintaining a normal blood pH. The lungs do this by blowing off carbon dioxide, since most of the acid in the body is carbonic acid, which is made from carbon dioxide during metabolic processes. The amount of carbon dioxide removed is controlled by your breathing rate. The kidneys maintain blood pH by controlling the amount of bicarbonate, which is a base that is excreted from the body. The kidneys also control the amount of acids excreted from the body. Respiratory alkalosis occurs when the lungs are blowing off more carbon dioxide than the body is producing. This usually occurs from hyperventilation. Your body's immediate response, after about 10 minutes of respiratory alkalosis, is a process called cell buffering. During cell buffering, hydrogen ions found in hemoglobin, proteins and phosphates, move out of the cells and into the extracellular fluid. There they combine with bicarbonate molecules and form carbonic acid. This process helps to reduce the amount of bicarbonate in the body and increase the amount of acid. However, while cell buffering occurs quickly, it does not have a huge effect on the body's pH. After about two to six hours of respiratory alkalosis the kidneys respond. They begin to limit the excretion of hydrogen and other acids and increase the excretion of bicarbonate. It usually takes the kidneys two or three days to reach a new steady state. In chronic respiratory alkalosis, the pH may constantly be high, but the body learns to adapt to it over time, with the help of the kidneys. Continue reading >>

Handling Ph: How Your Body Regulates Acidity

Handling Ph: How Your Body Regulates Acidity

When it comes to pH, your body likes to keep a tight control of the balance between acidity and alkalinity. The normal range for pH in your body is between 7.35-7.45 so, very slightly alkaline. At times, this balance can be disrupted. I will be talking about what occurs. Now, we must think about the ways you can control acidity. One is to remove/add acid, the other is to remove/add base. So how can we do this? There are two places where we can do this — the lungs and the kidneys. The lungs may seem like a strange place for controlling pH however, if we consider how CO2 is transported from the tissues (read more here), we see that CO2 dissociates into carbonic acid. Hence, the higher the CO2 levels in the tissues, the lower the pH gets (more acidic). So, if we are experiencing an Acidosis (low pH), if we decrease our CO2, we can increase the pH. We do this by hyperventilating and blowing off our CO2 however, this is limited by the amount of CO2 we have in our bodies; once we have blown off all our CO2, there is no more that the lungs can do to help us compensate. Conversely, if we experience an Alkylosis (high pH) our lungs can try to compensate by slowing down our breathing to increase our CO2 however, this can be dangerous because it can cause hypoxia (lack of oxygen). The benefit of respiratory compensation is that it happens very quickly (a few minutes) however, it has a very limited range of effectiveness. The kidneys deal in acids and bases, they can excrete/retain H+ if needed and they also control the excretion/retention of bicarbonate (HCO3-). If you are acidotic, your kidneys will try to excrete H+ and retain HCO3-, if you are alkylotic, your kidneys will try to retain H+ and excrete HCO3-. The drawback of this is that it takes a few days to be effective but, Continue reading >>

Explain How The Respiratory System Compensates For Metabolic Acidosis And Alkalosis.?

Explain How The Respiratory System Compensates For Metabolic Acidosis And Alkalosis.?

Explain how the respiratory system compensates for metabolic acidosis and alkalosis.? Are you sure you want to delete this answer? Best Answer: The respiratory system cam compensate for acidosis by increasing the rate of respiration which lowers the carbon dioxide dissolved in the blood. Similarly, alkalosis can be compensated for by decreasing the rate of respiration, increasing the carbon dioxide dissolved in the blood. The driving mechanism is controlled by neurons in the floor of the fourth ventricle of the brain. They sense the pH of the cerebrospinal fluid which mirrors the pH of the blood and modulate the respiration rate. If the pH is low, they increase the respiration rate, and if the pH is high, they decrease the respiration rate. This mechanism is the fundamental determinant of the rate of respiration. That is, the need for oxygen is not the primary determinant of the respiration rate. Upload failed. Please upload a file larger than 100x100 pixels We are experiencing some problems, please try again. You can only upload files of type PNG, JPG, or JPEG. You can only upload files of type 3GP, 3GPP, MP4, MOV, AVI, MPG, MPEG, or RM. You can only upload photos smaller than 5 MB. You can only upload videos smaller than 600MB. You can only upload a photo (png, jpg, jpeg) or a video (3gp, 3gpp, mp4, mov, avi, mpg, mpeg, rm). Video should be smaller than 600mb/5 minutes Video should be smaller than 600mb/5 minutes Continue reading >>

Respiratory Regulation Of Acid Base Balance

Respiratory Regulation Of Acid Base Balance

The acid base balance is vital for normal bodily functions. When this equilibrium is disrupted, it can lead to severe symptoms such as arrhythmias and seizures. Therefore, this balance is tightly regulated. In this article, we will look at the buffering system, responses of the respiratory and urinary systems and relevant clinical conditions. Blood has the ability to be insensitive to small changes in pH, which is a characteristic known as “buffering”. This is due to the basal levels of bicarbonate and hydrogen ions in blood. The chemical reaction is given by: This reaction can be used to control pH, as will be discussed in the next section. For example, in metabolically active tissues, there is an increase in hydrogen ions. These can then react with bicarbonate in the red blood cells to form carbon dioxide which can then be exhaled by the lungs. The compensatory systems of the body rely on this equation. This will be discussed in more detail later. Henderson-Hassalbalch Equation The Henderson-Hassalbalch equation relates the pH to the ratio between the concentration of bicarbonate and the partial pressure of carbon dioxide. It is given by: This shows that the ratio between bicarbonate production and partial pressure of carbon dioxide drive the pH levels of the blood. By increasing bicarbonate levels, the pH will rise and turn more alkaline, and by increasing the partial pressure of carbon dioxide the pH of blood will fall and turn acidic. The usual range of blood pH is from 7.35 to 7.45. When pH levels drop below 7.35, it is said to be acidotic, and when pH levels rise above 7.45 it is said to be alkalotic. How is Balance Restored? When blood pH deviates from the normal range, there are two body systems which are activated to restore equilibrium. The respiratory sy Continue reading >>

5.5 Metabolic Acidosis - Compensation

5.5 Metabolic Acidosis - Compensation

Acid-Base Physiology 5.5.1 Hyperventilation Compensation for a metabolic acidosis is hyperventilation to decrease the arterial pCO2. This hyperventilation was first described by Kussmaul in patients with diabetic ketoacidosis in 1874. The metabolic acidosis is detected by both the peripheral and central chemoreceptors and the respiratory center is stimulated. The initial stimulation of the central chemoreceptors is due to small increases in brain ISF [H+]. The subsequent increase in ventilation causes a fall in arterial pCO2 which inhibits the ventilatory response. Maximal compensation takes 12 to 24 hours The chemoreceptor inhibition acts to limit and delay the full ventilatory response until bicarbonate shifts have stabilised across the blood brain barrier. The increase in ventilation usually starts within minutes and is usually well advanced at 2 hours of onset but maximal compensation may take 12 to 24 hours to develop. This is �maximal� compensation rather than �full� compensation as it does not return the extracellular pH to normal. In situations where a metabolic acidosis develops rapidly and is short-lived there is usually little time for much compensatory ventilatory response to occur. An example is the acute and sometimes severe lactic acidosis due to a prolonged generalised convulsion: this corrects due to rapid hepatic uptake and metabolism of the lactate following cessation of convulsive muscular activity, and hyperventilation due to the acidosis does not occur. The expected pCO2 at maximal compensation can be calculated from a simple formula The arterial pCO2 at maximal compensation has been measured in many patients with a metabolic acidosis. A consistent relationship between bicarbonate level and pCO2 has been found. It can be estimated from the 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 >>

Intro To Arterial Blood Gases, Part 2

Intro To Arterial Blood Gases, Part 2

Arterial Blood Gas Analysis, Part 2 Introduction Acute vs. Chronic Respiratory Disturbances Primary Metabolic Disturbances Anion Gap Mixed Disorders Compensatory Mechanisms Steps in ABG Analysis, Part II Summary Compensatory Mechanisms Compensation refers to the body's natural mechanisms of counteracting a primary acid-base disorder in an attempt to maintain homeostasis. As you learned in Acute vs. Chronic Respiratory Disturbances, the kidneys can compensate for chronic respiratory disorders by either holding on to or dumping bicarbonate. With Chronic respiratory acidosis: Chronic respiratory alkalosis: the kidneys hold on to bicarbonate the kidneys dump bicarbonate With primary metabolic disturbances, the respiratory system compensates for the acid-base disorder. The lungs can either blow off excess acid (via CO2) to compensate for metabolic acidosis, or to a lesser extent, hold on to acid (via CO2) to compensate for metabolic alkalosis. With Metabolic acidosis: Metabolic alkalosis: ventilation increases to blow off CO2 ventilation decreases to hold on to CO2 The body's response to metabolic acidosis is predictable. With metabolic acidosis, respiration will increase to blow off CO2, thereby decreasing the amount of acid in the blood. Recall that with metabolic acidosis, central chemoreceptors are triggered by the low pH and increase the drive to breathe. For now, it is only important to learn (qualitatively) that there is a predictable compensatory response to metabolic acidosis. Later, during your 3rd or 4th year rotations, you might learn how to (quantitatively) determine if the compensatory response to metabolic acidosis is appropriate by using the Winter's Formula. The body's response to metabolic alkalosis is not as complete. This is because we would need to hypov Continue reading >>

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