Respiratory or Metabolic
Acidosis or Alkalosis
Objectives
• Discuss causes of respiratory and metabolic acid base disturbances.
• Identifyyp pH values, CO2 values and HCO3 values in acid base imbalances. • Identify the acid base imbalance based on clinical conditions. • Define supportive treatment of acid base disturbance.
Respiratory acidosis.
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1 Causes Respiratory Acidosis
• Any condition that impairs pulmonary ventilation and the removal of CO2. Leads to an increase in CO2 circulating in the blood.. – respiratory depression – respiratory arrest – Medications (narcotics) – cardiac arrest – neuromuscular impairment – chest wall injury - flail chest, pneumothorax – pulmonary - obstruction, COPD, asthma, pulmonary edema
S/S Respiratory Acidosis
• SOB, chronic cough, or wheezing • Confusion, irritability, or lethargy
Respiratory Acidosis
• Treatment – Improve ventilation • assist ventilation •addseminister oxygen(hypoxemia leads to acidosis)
– Consider causes and initiate treatment • Bronchodilators • narcan
2 Respiratory acidosis.
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Metabolic acidosis.
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Metabolic Acidosis
• Four common forms of metabolic acidosis – Lactic acidosis – Diabetic ketoacidosis – Renal failure – Diarrhea – Ingestion of toxins
3 S/S Metabolic Acidosis
• Confusion, lethargy, stupor or coma • Kussmaul’s respiration, deep, rapid respiration • Dysrhythmia’s
Lactic Acidosis
• Lactic acid is produced when a large number of cells are inadequately perfused with oxygen, anaerobic metabolism. – The end product of anaerobic metabolism is lactic acid. • Causes of Lactic Acidosis – Seizure – ischemia to large muscles or organs – circulatory failure – shock
S/S Lactic acidosis
• Cardiovascular compromise: – Cyanosis, cold extremities, tachycardia, hypotension • Dehydration – Thirsty, dry oral mucosa, warm, dry skin • Hyperventilation • Lethargy, stupor or coma • Abdominal pain, vomiting
4 Lactic Acidosis
• Treatment – reestablish tissue perfusion and cardiac output – ventilation – rehydration to support circulation – sodium bicarbonate administration if the patient is in cardiac arrest
Diabetic Ketoacidosis (DKA) • Usually a complication of diabetes. • Insulin is needed for cells to metabolize glucose for immediate use, or store it in the liver for future use. • When the cells don’t have glucose available the cells use fatty acids for energy. • When the fatty acids breakdown they produce ketones, a strong acid. • The acidosis results when a patient fails to take adequate insulin or when the need for insulin increases(infection, trauma).
Diabetic Ketoacidosis • The respiratory system will respond by increasing rate and depth of ventilation.
(Kussmaul) Increasing the amount of CO2 being blown off in an attempt to bring the pH within normal range. • Treatment – Administration of normal saline for volume replacement – Administration of insulin
5 Renal Failure
• The kidneys help maintain acid base balance by reabsorbing bicarbonate or excreting hydrogen ions. Renal failure affects the kidneys ability to function. – Acidosis can result because the kidneys are unable to excrete the excess H+ ions that are produced by normal metabolism and ammonia is not being excreted. – The bicarb buffer system is disrupted because the kidneys are not dumping HCO3 back into the blood stream.
Ingestion of Toxins
• Causes of metabolic acidosis – Ingestion of: Ethylene glycol(antifreeze), methanol(windshield washer fluid), salicylate(aspirin) • Treatment – GI evacuation – Hemodialysis –Diuresis – Hydration to promote excretion – Antidote therapy
Metabolic acidosis.
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S/S Respiratory Alkalosis
• Muscle twitching, tingling and numbness of the fingers • Nervousness, irritability , agitation • Convulsions, coma
Respiratory Alkalosis
• Treatment – place patient on low concentration oxygen – provide calming measures – treat underlying problem
Metabolic Alkalosis (rare)
•Causes – Ingestion of large amounts of absorbable base sodium bicarbonate or calcium carbt(tid)bonate(antacids)
– Excessive IV administration of alkali(NaHCO3) – Diuretic use(excrete too much Hydrogen ion) – Vomiting(gastric acid lost) – only initially as vomiting becomes severe dehydration develops and you see acidosis.
Metabolic Alkalosis
• Treatment – aimed at correcting the underlying condition – if volume depleted rehydrate
8 Arterial Blood Gas (ABG’s)
• Blood gases measure the pH, O2, CO2 (acid) and HCO3 (base) content of the blood. • The test is used to evaluate respiratory diseases and conditions that affect the lungs. • The test also gives information on how well the kidneys are functioning.
ABG’s
• Normal Values at sea level: – PaO2 – 75-100mmhg – PaCO2 – 35-45mmhg – pH – 7.35-7.45 – HCO3 – 22-26meq/L
Acid - Base
If you have a CO2 of 55 What do you expect your pH to be?
9 Correct answer pH<7.35
What is the state of acid base balance?
Correct answer Acidosis
Is your patient in respiratory arrest or hyperventilating?
Correct answer: Arrest
Is this metabolic or respiratory acidosis?
10 Correct answer: Respiratory acidosis
Acid - Base
If you have a pH <7.35, what do you
expect your CO2 to be?
Correct answer: CO2 >45mmhg
What is the state of acid base balance?
11 Correct answer: Acidosis
Your patient is a diabetic, is this metabolic or respiratory acidosis?
Correct answer: Metabolic acidosis
Acid - Base
You arrive to find your patient leaning forward breathing rapid c/o cramping and pain in fingers, and hands. What do you expect her pH to be?
12 Correct answer: pH >7.45
Is your patient in respiratory or metabolic alkalosis?
Correct answer: Respiratory
Why is she in respiratory alkalosis?
Correct answer: Blowing off too much CO2
13 Acid - Base
Your patient is in cardiac arrest. What do you expect the pH to be?
Correct answer: pH <7.35
What is the acid base state of this patient?
Correct answer: Acidosis
Why is this patient acidotic?
14 Correct answer: Anaerobic metabolism with increased production of acids and no circulation for buffer systems to do their work, maintaining homeostasis.
Is this patient in metabolic or respiratory acidosis?
Correct answer: Metabolic and respiratory acidosis, because there is no circulation and no ventilation
H2O HCO3 H2CO3
CO2 H+
O2 Cl O2
H+ CO2+H20 H2CO3 H+HCO3 H CO CO 2 3 Cl 2 H CO 2 3 H2O HCO 3 H2CO3 HCO3 + H2O H O2 Cl CO2
Angie Brindowski, RN, EMT P, MCEMS
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