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Metabolic And Respiratory Acidosis And Alkalosis

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 >>

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 >>

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 >>

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/ Respiratory Acidosis And Alkalosis

Metabolic/ Respiratory Acidosis And Alkalosis

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

Abg: Respiratory Acidosis/metabolic Alkalosis

Abg: Respiratory Acidosis/metabolic Alkalosis

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

Metabolic Vs. Respiratory Acidosis

Metabolic Vs. Respiratory Acidosis

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

The Quick And Dirty Guide To Acid Base Balance | Medictests.com

The Quick And Dirty Guide To Acid Base Balance | Medictests.com

Your patient has a ph of 6.9 Is he acidic or alkalotic? Your patient has a ph of 7.4 Is he acidic or alkalotic? Your patient has a ph of 7.7 Is he acidic or alkalotic? Your patient has a ph of 7.25 Is he acidic or alkalotic? Your patient has a ph of 7.43 Is he acidic or alkalotic? Your patient has a ph of 8.0 Is he acidic or alkalotic? 1. acidic 2. normal 3. Alkaline 4. Acidic 5. Normal 6. Alkaline You take in oxygen by inhaling, your body turns oxygen into carbon dioxide, you exhale and remove the carbon dioxide from your body. Carbon dioxide is "respiratory acid."When you're not breathing adequately, you are not getting rid of this "respiratory acid" and it builds up in the tissues. The extra CO2 molecules combine with water in your body to form carbonic acid and makes your pH go up. This is bad. We can measure the amount of respiratory acid in the arterial blood using blood gases. They measure the amount of each gas in your blood. We measure the pH, the amount of carbon dioxide (PaCO2) and the amount of oxygen in the blood (PaO2). PaCO2 is the partial pressure of carbon dioxide. We can measure it to see how much respiratory acid (CO2) there is in the blood. We use arterial blood gas tests to check it. How much respiratory acid (CO2) should there be? The normal value is 35-45 mmHg (mmHg just means millimeters of mercury, its a measurement of pressure.) The (a) in PaCO2 just stands for arterial. If you measured venous blood gasses, the levels are different and PvCO2 is used. If CO2 is HIGH, it means there is a buildup of respiratory acids because he's not breathing enough CO2 away. If your pH is acidic, and your CO2 is HIGH, its considered respiratory acidosis. If CO2 is LOW, it means there are not enough respiratory acids because he's probably hyperventilating too mu Continue reading >>

Types Of Disturbances

Types Of Disturbances

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

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 >>

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 >>

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 >>

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 >>

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 >>

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