Class4_AcidBase_StudentCopy_Spring2024 (4).pptx

Acid-Base Balance CLASS 4 NRSG3301 C RY S TA L T R E I G E B S C N R N M N N P CREATED BY C.TREIGE WINTER 2024 Learning Demonstrate an understanding of the concept of acid-base balance. Objectives Demonstrate an understanding of...

Acid-Base Balance CLASS 4 NRSG3301 C RY S TA L T R E I G E B S C N R N M N N P CREATED BY C.TREIGE WINTER 2024 Learning Demonstrate an understanding of the concept of acid-base balance. Objectives Demonstrate an understanding of the normal arterial blood gas values. Demonstrate an understanding of abnormal arterial blood gas values. Recognize when an individual has an acid-base imbalance. Discuss the types of acid-base imbalances. Discuss the causes of acid-base imbalances. Discuss the treatment of acid-base imbalances. CREATED BY C.TREIGE WINTER 2024 Scope A continuum from acidotic (lower than normal pH) to optimal balance (normal pH and other parameters) in the middle and alkalotic (higher than normal pH) on the other end. CREATED BY C.TREIGE WINTER 2024 Acid-Base Balance Process of regulating the pH, bicarbonate concentration, and partial pressure of carbon dioxide of body fluids. CREATED BY C.TREIGE WINTER 2024 Acid-Base Balance and Imbalance Acid-Base Balance Acid-Base Imbalance ◦ Expected in all well individuals ◦ Develops as a complication of ◦ Requires normal physiological another underlying condition functioning ◦ Never considered “normal,” but ◦ Indication of homeostasis may be “expected” if a chronic condition (e.g., compensation) is present CREATED BY C.TREIGE WINTER 2024 Types of Respiratory acidosis Acid-Base Imbalances Increase in carbon dioxide levels Metabolic acidosis Decrease in bicarbonate ions Respiratory alkalosis Decrease in carbon dioxide levels Metabolic alkalosis Loss of hydrogen ions through kidneys/GI tract Copyright © 2019 by Elsevier Inc. All rights reserved. CREATED BY C.TREIGE WINTER 2024 Acidosis Caused by: ◦ Retention of too much acid ◦ Loss of too much base Respiratory acidosis ◦ CO2 retention Metabolic acidosis ◦ HCO3 loss or H+ retention CREATED BY C.TREIGE WINTER 2024 Alkalosis Caused by: ◦ Retention of too much base ◦ Loss of too much acid Respiratory alkalosis ◦ CO2 loss Metabolic alkalosis ◦ HCO3 excess or H+ loss CREATED BY C.TREIGE WINTER 2024 Normal Acid Base Values CREATED BY C.TREIGE WINTER 2024 Acid-Base Buffering Systems 1. Chemical Buffers Present in our bodily fluids and act immediately to bind or release hydrogen ions and help promote acid-base balance in the body. Carbonic-acid-bicarbonate buffer system Buffer solution made of carbonic acid (H₂CO₃, a weak acid), and bicarbonate (HCO₃). Plays the bigger role in regulating the pH of the blood. Phosphate buffer system Consists of acidic phosphate ions and alkaline phosphate ions that work to neutralize pH. Protein buffers: albumin, globulins, and hemoglobin Proteins work well because they have both positive and negative charges on their surface, and can bind with acids to neutralize them. (Lewis, 2023) CREATED BY C.TREIGE WINTER 2024 Acid-Base Buffering Systems (con’t) 2. Respiratory System Second line of defense, and is able to control the amount of carbon dioxide in the arterial blood by regulating breathing. High CO2 level response In response to high CO₂ levels in the arterial blood, the respiratory system will increase the depth and rate of breathing, leading to hyperventilation. In this case, hyperventilation is the body’s attempt to reduce excess CO₂ and thus reduce excess hydrogen ions Low CO2 level response The body will decrease rate and depth of breathing, leading to hypoventilation. In this case, hypoventilation is the body's attempt to retain more CO₂ and therefore, more hydrogen ions. (Lewis, 2023) CREATED BY C.TREIGE WINTER 2024 Acid-Base Buffering Systems (con’t) 3. Renal System The third line of defense; slower to respond, but longer-acting Alkalosis response If the renal system senses that the blood pH is too high/alkaline (alkalosis is present), it will increase excretion of bicarbonate (reduce bicarbonate) and increase reabsorption of hydrogen ions (retain more hydrogen ions). Acidosis response If the renal system senses that the blood pH is too low/acidic (acidosis is present), the kidneys will increase reabsorption of bicarbonate, to retain more of it, and excrete more hydrogen ions. (Lewis, 2023) This Photo by Unknown Author is licensed under CC BY CREATED BY C.TREIGE WINTER 2024 Arterial Blood Gas (Hutzel, 2020) CREATED BY C.TREIGE WINTER 2024 Compensation: Respiratory CREATED BY C.TREIGE WINTER 2024 Compensation: Metabolic CREATED BY C.TREIGE WINTER 2024  Metabolic Acidosis Renal Impairment, DM, starvation Prolonged diarrhea (prolonged loss of sodium bicarb.) Etiology Excessive chloride infusion Excessive acid ingestion Cardiac arrest Decrease appetite, N&V, abdominal pain Weakness, fatigue, headache, decreased LOC Manifestations Dysrhythmias (bradycardia), warm flushed skin, Hyperventilation, Kussmauls respirations, dyspnea Monitor ABGs, record ins/outs, monitor LOC, frequent vital signs Therapies IV sodium bicarb may be required Tx underlying problem CREATED BY C.TREIGE WINTER 2024  Metabolic Alkalosis Excessive acid loss r/t vomiting or gastric loss Excessive use of K losing diuretics Excessive adrenal corticoid hormone (Cushings syndrome, Etiology hyperaldosteronism) Antacids use Sodium bicarb infusion Confusion, decreased LOC Hyperreflexia, tetany Dysrhythmias Manifestations Hypotension Seizures Respiratory failure Monitor ABGs, measure ins/outs, monitor LOC, frequent vital signs Oxygen therapy Therapies IV fluids Tx underlying problem CREATED BY C.TREIGE WINTER 2024  Respiratory Acidosis Acute lung conditions (pneumonia, near drowning, Pulmonary edema Chronic lung conditions (asthma, cystic fibrosis, emphysema) OD of narcotics or sedatives Etiology Traumatic brain injury Mechanical injury Airway obstruction Headache, warm flush skin, elevated pulse, blurred vison, irritability, altered mental status, decreased loc, cardiac arrest Manifestations Chronic respiratory acidosis Weakness Dull headache, sleep disturbances with daytime sleepiness, impaired memory, personality changes Frequent respiratory assessment Monitor mental status Place in semi Fowlers-Fowlers Monitor airway and ventilation, oral airway and mech vent if necessary Therapies Aerosols, bronchodilators, antibiotics, postural drainage Ins/Outs, VS, ABG Naloxone, CREATED BY C.TREIGE WINTER 2024  Respiratory Alkalosis Anxiety evoked hyperventilation High fever (r/t increased metabolic demands causing hyperventilation) Hypoxia (r/t increased metabolic demands causing hyperventilation) Gram negative bacteremia (associated hyperventilation) Etiology Aspirin overdose (stimulates chemoreceptors to increase respiration) Encephalitis (intercranial pathology causing neurogenic hyperventilation) Pregnancy (high progesterone levels stimulate respiratory centre) Mechanical ventilation (if rate and tidal volume are excessive) Light-headedness Feeling of panic and difficulty concentrating Numbness and tingling, Tremors Might see s/s of low calcium (Alkalosis promotes the binding of calcium to albumin and can reduce the fraction of ionized calcium in the blood) Positive Chvostek’s (twitching of facial muscles in response to tapping over the area of Manifestations the facial nerve) and Trousseau’s sign (carpopedal spasm that results from ischemia, such as that induced by pressure applied to the upper arm from an inflated bp cuff) Sensations of chest tightness and palpitations Seizures and loss of consciousness ( The mechanisms that trigger these seizures are unknown, however a rise in brain pH is known to enhance neuronal excitability) CREATED BY C.TREIGE WINTER 2024 Respiratory Alkalosis (con’t) Frequent respiratory assessment Slow deep breathing Therapies Brown paper bag Sedative CREATED BY C.TREIGE WINTER 2024 Arterial Blood Gas (ABG) Analysis Copyright © 2019 Elsevier Canada, a division of Reed Elsevier Canada, Ltd. CREATED BY C.TREIGE WINTER 2024 Arterial Blood Gas (ABG) Analysis Arterial blood gases (ABGs) ◦ Steps for interpretation of blood gas levels ◦ Step 2. Look at the pH level and ◦ Step 1. Look at the PaO2 level and answer this question: Is the pH on the answer this question: Does the PaO2 acid or alkaline side of 7.40? show hypoxemia? ◦ Normal range = 7.35 to 7.45 ◦ Mean = 7.40 ◦ Normal PaO2 levels are age-dependent ◦ A PaO2 < 40 mm Hg is a life-threatening ◦ Step 3. Look at the PaCO2 level and situation answer this question: Does the PaCO2 ◦ Requiring immediate action show respiratory acidosis, alkalosis, or normalcy? ◦ Normal range = 35 to 45 mm Hg CREATED BY C.TREIGE WINTER 2024 Arterial Blood Gas (ABG) Analysis ◦ Step 4. Look at the HCO3− level and ◦ Step 5. Look again at the pH level and answer this question: Does the answer this question: Does the pH HCO3− level show metabolic show a compensated or an acidosis, alkalosis, or normalcy? uncompensated condition? ◦ Normal range = 22 to 26 mEq/L ◦ Uncompensated ◦ Compensated CREATED BY C.TREIGE WINTER 2024 CREATED BY C.TREIGE WINTER 2024 Practice questions Lilly studies acid–base balance. Which two organs are responsible for acid excretion, which helps maintain acid–base balance? A. Lungs and kidneys. B. Kidneys and liver. C. Bladder and bowel. D. Lungs and bladder. Lilly studies the difference between metabolic acidosis and alkalosis. _____________ _____________ increases blood bicarbonate (HCO3–) CREATED BY C.TREIGE WINTER 2024 Practice questions Interpret the following ABG: pH - 7.48 PCO2 - 37 mmHg PO2- 91 mmHg O2Sat - 97% HCO3 - 38 mEq/L CREATED BY C.TREIGE WINTER 2024 References Giddens, J. F. (2017). Concepts for nursing practice (2nded.). St. Louis, MO: Elsevier. Lewis, S. L., Dirksen, S. R., Heitkemper, M.M., Bucher, L., Barry, M.A., Goldsworthy, S., Lok, J., & Tyerman, J. (Eds.). (2018). Medical-surgical nursing in Canada: Assessment and management of clinical problems (4thCdn. ed.). Toronto, ON: Elsevier. CREATED BY C.TREIGE WINTER 2024