Acid Base Balance Review Questions
A client complains of a dull headache and dizziness and has an increased pulse rate. The results of arterial blood gas analysis are as fol- lows: pH 7.26; partial pressure of carbon dioxide, 50 mm Hg; and bicarbonate, 24 mEq/L. These findings indicate which of the following acid-base imbalances? 1. Respiratory alkalosis. 2. Respiratory acidosis. 3. Metabolic acidosis. 4. Metabolic alkalosis.
ANSWER: 2. The pH of 7.26 indicates that the body is in a state of acidosis. The elevated partial pressure of carbon dioxide value accompanied by a normal bicarbonate value indicates that the acid-base imbal- ance is respiratory acidosis. The additional clinical findings of a headache, dizziness, and increased pulse rate, resulting from the elevated partial pres- sure of carbon dioxide, further supports this diagno- sis.
A client appears flushed and has shallow respirations. The arterial blood gas report shows the following: pH, 7.24; partial pressure of arterial car- bon dioxide (PaCO2), 49 mm Hg; bicarbonate (HCO3), 24 mEq/L. These findings are indicative of which of the following acid-base imbalances? 1. Metabolic acidosis. 2. Metabolic alkalosis. 3. Respiratory acidosis. 4. Respiratory alkalosis.
ANSWER: 3 . The pH of 7.24 indicates that the client is acidotic. The PaCO2 value of 49 mm Hg is elevated. The HCO3 value of 24 mEq/L is normal. The client is in uncompensated respiratory acidosis. Hypoven- tilation and a flushed appearance are additional clinical manifestations of respiratory acidosis.
An 80-year-old client is admitted with nausea and vomiting. He has a history of heart failure and is being treated with digoxin (Lanoxin). He tells the nurse he has been nauseated for a week and began vomiting 2 days ago. Laboratory values indicate that he has hypokalemia. Because of these clinical find- ings, the nurse should assess the client carefully for signs of which of the following conditions? 1. Chronic renal failure. 2. Exacerbation of heart failure. 3. Digoxin toxicity. 4. Metabolic acidosis.
ANSWER: 3. Nausea and vomiting, along with hypokalemia, are likely indicators of digoxin toxic- ity. Hypokalemia is a common cause of digoxin tox- icity; therefore, serum potassium levels should be carefully monitored if the client is taking digoxin. The earliest clinical signs of digoxin toxicity are anorexia, nausea, and vomiting. Bradycardia, other dysrhythmias, and visual disturbances are also common signs. Chronic renal failure usually causes hyperkalemia. With persistent vomiting, the client is more likely to develop metabolic alkalosis than metabolic acidosis.
A client exhibits increased restlessness. The results of the arterial blood gas test are as follows: pH, 7.52; partial pressure of carbon dioxide, 38 mm Hg; bicarbonate, 34 mg/L. The nurse should plan care based on the fact that these findings indicate which of the following acid-base imbalances? 1. Respiratory alkalosis. 2. Respiratory acidosis. 3. Metabolic acidosis. 4. Metabolic alkalosis.
ANSWER: 4. The pH of 7.52 indicates that the body isin a state of alkalosis. The partial pressure of carbon dioxide value is normal and the bicarbonate value is elevated. The increased bicarbonate value indicates that the acid-base imbalance is metabolic alkalosis. Restlessness can be a clinical finding in metabolic alkalosis.
The nurse is providing care for several clients who are at risk for acid-base imbalance. Which client is most at risk for respiratory acidosis? 1. A 68-year-old client with chronic emphysema 2. A 58-year-old client who uses antacids every day 3. A 48-year-old client with an anxiety disorder 4. A 28-year-old client with salicylate intoxication
Ans: 1 Clients at greatest risk for acute acidosis are those with problems that impair breathing. Older adults with chronic health problems are at greater risk for developing acidosis. Whereas a client who misuses antacids is at risk for metabolic alkalosis, a client with anxiety is at risk for respiratory alkalosis. A client with salicylate intoxication is at risk for metabolic acidosis. Focus: Prioritization; Test Taking Tip: Respiratory acid-base disorders are related to respiratory function. When a client has a chronic respiratory illness, he or she is at risk for a respiratory acid-base imbalance.
The client with respiratory failure is receiving mechanical ventilation and continues to produce arterial blood gas results indicating respiratory acidosis. Which change in ventilator setting should the nurse expect to correct this problem? 1. Increase in ventilator rate from 6 to 10 breaths/min 2. Decrease in ventilator rate from 10 to 6 breaths/min 3. Increase in oxygen concentration from 30% to 40% 4. Decrease in oxygen concentration from 40% to 30%
Ans: 1 The blood gas component responsible for respiratory acidosis is carbon dioxide, thus increasing the ventilator rate will blow off more carbon dioxide and decrease or correct the acidosis. Changes in the oxygen setting may improve oxygenation but will not affect respiratory acidosis.
The student nurse, under the supervision of an RN, is reviewing a client's arterial blood gas results and notes an acute increase in arterial partial pressure of carbon dioxide (Paco2) to 51 mm Hg compared with the previous results. Which statement by the student nurse indicates accurate understanding of acid-base balance for this client? 1. "When the Paco2 is acutely elevated, the blood pH should be lower than normal." 2. "This client should be taught to breathe and rebreathe in a paper bag." 3. "An elevated Paco2 always means that a client has an acidosis." 4. "When a client's Paco2 is increased, the respiratory rate should decrease to compensate."
Ans: 1 This client's Paco2 is elevated (normal is 35 to 45 mm Hg). Whenever the Paco2 level changes acutely, the pH changes to the same degree, in the opposite direction. As the amount of CO2 begins to rise above normal in brain blood and tissues, these central receptors trigger the neurons to increase the rate and depth of breathing (hyperventilation). For these reasons, answers 2, 3, and 4 are inaccurate.
The charge nurse assigned the care of a client with acute kidney failure and hypernatremia to a new-graduated RN. Which actions can the new-graduate RN delegate to the unlicensed assistive personnel (UAP)? Select all that apply. 1. Providing oral care every 3 to 4 hours 2. Monitoring for indications of dehydration 3. Administering 0.45% saline by IV line 4. Record urine output when client voids 5. Assessing daily weights for trends 6. Help the client change position every 2 hours
Ans: 1, 4, 6 Providing oral care, assisting clients to reposition, and recording urine output are within the scope of practice of the UAP. Monitoring and assessing clients, as well as administering IV fluids, require the additional education and skills of the RN.
Which specific instruction does the charge nurse give the unlicensed assistive personnel (UAP) helping to provide care for a client who is at risk for metabolic acidosis? 1. Check to see that the client keeps his oxygen in place at all times. 2. Inform the nurse immediately if the client's respiratory rate and depth increases. 3. Record any episodes of reflux or constipation. 4. Keep the client's ice water pitcher filled at all times.
Ans: 2 If acidosis is metabolic in origin, the rate and depth of breathing increase as the hydrogen ion level rises. Breaths are deep and rapid and not under voluntary control, a pattern called Kussmaul respiration. The client may not require oxygen. Although it's important to record reflux and constipation, this is not related to metabolic acidosis nor is keeping the water pitcher full specific to this condition
The client has a nasogastric (NG) tube connected to intermittent wall suction. The student nurse asks why the client's respiratory rate and depth has decreased. What is the nurse's best response? 1. "It's common for clients with uncomfortable equipment such as NG tubes to have a lower rate of breathing." 2. "The client may have a metabolic alkalosis due to the NG suctioning, and the decreased respiratory rate is a compensatory mechanism." 3. "Whenever a client develops a respiratory acid-base problem, decreasing the respiratory rate helps correct the problem." 4. "The client is hypoventilating because of anxiety, and we will have to stay alert for the development of respiratory acidosis."
Ans: 2 Nasogastric suctioning can result in a decrease in acid components and metabolic alkalosis. The client's decrease in rate and depth of ventilation is an attempt to compensate by retaining carbon dioxide. The first response may be true, but it does not address all the components of the question. The third and fourth answers are inaccurate.
Which client would the charge nurse assign to the step-down unit nurse who was floated to the intensive care unit for the day? 1. A 68-year-old client on a ventilator with acute respiratory failure and respiratory acidosis 2. A 72-year-old client with chronic obstructive pulmonary disease (COPD) and normal blood gas values who is ventilator dependent 3. A newly admitted 56-year-old client with diabetic ketoacidosis receiving an insulin drip 4. A 38-year-old client on a ventilator with narcotic overdose and respiratory alkalosis
Ans: 2 The client with COPD, although ventilator dependent, is in the most stable condition of the clients in this group and should be assigned to the float nurse from the step-down unit. Clients with acid-base imbalances often require frequent laboratory assessment and changes in therapy to correct their disorders. In addition, the client with diabetic ketoacidosis is a new admission and require an in-depth admission assessment. All three of these clients need care from an experienced critical care nurse
. The nurse is admitting an older adult client to the acute care medical unit. Which assessment factor alerts the nurse that this client has a risk for acid- base imbalances? 1. History of myocardial infarction (MI) 1 year ago 2. Antacid use for occasional indigestion 3. Shortness of breath with extreme exertion 4. Chronic renal insufficiency
Ans: 4 Risk factors for acid-base imbalances in older adults include chronic kidney disease and pulmonary disease. Occasional antacid use will not cause imbalances, although antacid abuse is a risk factor for metabolic alkalosis. The MI occurred 1 year ago and is no longer a risk factor. Focus: Prioritization.
The HCP orders serum electrolytes. To determine the effect of persistent vomiting, the RN should be most concerned with monitoring the: A. Chloride and sodium levels B. Phosphate and calcium levels C. Protein and magnesium levels D. Sulfate and bicarbonate levels
Answer: A. Chloride and sodium levels Option A: Sodium, which is concerned with the regulation of extracellular fluid volume, it is lost with vomiting. Chloride, which balances cations in the extracellular compartments, is also lost with vomiting, because sodium and chloride are parallel electrolytes, hyponatremia will accompany.
The RN is caring for a client with nasogastric tube that is attached too low suction. The RN assesses the client for symptoms of which acid-base disorder? A. Respiratory alkalosis B. Respiratory acidosis C. Metabolic acidosis D. Metabolic alkalosis
Answer: D. Metabolic alkalosis Option D: Loss of gastric fluid via nasogastric suction or vomiting causes metabolic alkalosis because of the loss of hydrochloric acid which is a potent acid in the body.
The nurse is caring for a client with a collapsed lung following a motor vehicle accident and reviews the client's newly resulted arterial blood gas values. Which of the following results most closely match this client's condition? 1. PaCO2 54, HCO3 24, pH 7.33 2. PaCO2 45, HCO3 29, pH 7.5 3. PaCO2 30, HCO3 22, pH 7.48 4. PaCO2 36, HCO3 18, pH 7.29
Correct: 1 1. PaCO2 54, HCO3 24, pH 7.33 Normal lab values are as follows: pH 7.35-7.45, PaCO2 35-45, and HCO3 22-26. This client's lab values reflect respiratory acidosis. When a client has a condition that prevents airflow in the lungs, it leads to CO2 retention, which then leads to respiratory acidosis. 2. PaCO2 45, HCO3 29, pH 7.5 These lab values reflect metabolic alkalosis, which would not be expected in a client with a collapsed lung. 3. PaCO2 30, HCO3 22, pH 7.48 These lab values reflect respiratory alkalosis, which means the client is blowing off excess CO2. When a client has a collapsed lung, airflow is impeded resulting in retained CO2. This increases the PaCO2 and decreases the pH, resulting in respiratory acidosis. 4. PaCO2 36, HCO3 18, pH 7.29 These lab values reflect metabolic acidosis, which is not a likely result in a client with a collapsed lung. Instead, the client's ABG values are expected to reflect respiratory acidosis because of lung trauma.
A client has been brought to the emergency department after developing pneumonia. The client's arterial blood gas results show respiratory alkalosis. Which of the following signs or symptoms would the nurse expect to see with this condition? Select all that apply. 1. Hyperventilation 2. Numbness and tingling in extremities 3. Confusion 4. Deep purple rash on the trunk. 5. Epigastric pain
Correct: 1, 2, 3, 5 1. Hyperventilation Respiratory alkalosis occurs as an alteration in normal blood gas patterns, typically as a result of conditions that overstimulate the respiratory system. This results in a decrease in hydrogen ion concentration because of a decrease in PaCO2. The classic sign is hyperventilation, often at a rate of over 40/minute. The client may experience tetany, numbness and tingling of the extremities as well as hyperreflexia and seizures. They may have nausea, emesis and cardiac dysrhythmias as well. 2. Numbness and tingling in extremities Respiratory alkalosis occurs as an alteration in normal blood gas patterns, typically as a result of conditions that overstimulate the respiratory system. This results in a decrease in hydrogen ion concentration because of a decrease in PaCO2. The classic sign is hyperventilation, often at a rate of over 40/minute. The client may experience tetany, numbness and tingling of the extremities as well as hyperreflexia and seizures. They may have nausea, emesis and cardiac dysrhythmias as well. 3. Confusion Respiratory alkalosis occurs as an alteration in normal blood gas patterns, typically as a result of conditions that overstimulate the respiratory system. This results in a decrease in hydrogen ion concentration because of a decrease in PaCO2. The classic sign is hyperventilation, often at a rate of over 40/minute. The client may experience tetany, numbness and tingling of the extremities as well as hyperreflexia and seizures. They may have nausea, emesis and cardiac dysrhythmias as well. 4. Deep purple rash on the trunk This is not a symptom of respiratory alkalosis. 5.Epigastric pain Respiratory alkalosis occurs as an alteration in normal blood gas patterns, typically as a result of conditions that overstimulate the respiratory system. This results in a decrease in hydrogen ion concentration because of a decrease in PaCO2. The classic sign is hyperventilation, often at a rate of over 40/minute. The client may experience tetany, numbness and tingling of the extremities as well as hyperreflexia and seizures. They may have nausea, emesis and cardiac dysrhythmias as well.
The nurse is caring for a client with respiratory acidosis due to a benzodiazepine overdose. Which of the following nursing interventions are appropriate for this client? Select all that apply. 1. Provide supplemental oxygen 2. Administer flumazenil as ordered 3. Administer alprazolam as ordered 4. Monitor respiratory status 5. Insert a nasogastric tube
Correct: 1, 2, 4 1. Provide supplemental oxygen A client in respiratory acidosis is breathing shallow and/or slow to the point where they cannot blow off adequate CO2 and it builds up in the blood, causing an acidic pH. The nurse should provide oxygen because the client would also have a low SpO2. 2. Administer flumazenil as ordered Flumazenil is the antidote to benzodiazepines, so it is appropriate to administer this drug. 3. Administer alprazolam as ordered If this client is conscious, they may be restless and anxious from a lack of oxygenation. Since alprazolam (Xanax) is a benzodiazepine, it is inappropriate to give. 4. Monitor respiratory status The nurse will monitor respiratory status. This client is at risk for respiratory failure and may need to be intubated, so it is appropriate for the nurse to closely monitor this client's breathing. 5. Insert a nasogastric tube Based on the information given, this client is not in need of a nasogastric tube.
The student nurse is discussing acid-base imbalances with the preceptor. The student correctly explains that respiratory acidosis results when which of the following occurs? 1. HCO3 is unable to be retained by the lungs 2. CO2 is unable to be released from the lungs 3. PaO2 is unable to be increased by the lungs 4. SaO2 is unable to be absorbed into the tissues
Correct: 2 1. HCO3 is unable to be retained by the lungs HCO3 is regulated by the kidneys, not the lungs. If HCO3 was being excessively lost by the kidneys, it would result in metabolic acidosis. Respiratory acidosis occurs when the lungs retain too much CO2. 2. CO2 is unable to be released from the lungs CO2 retention causes respiratory acidosis. CO2 is an acid, and the body regulates this through the respiratory system. When CO2 is prevented from being blown off, such as when the client has an airway obstruction or lung collapse, then respiratory acidosis occurs. 3. PaO2 is unable to be increased by the lungs While oxygen is obtained through the respiratory system, respiratory acidosis occurs because of an imbalance in the level of CO2, not O2. 4. SaO2 is unable to be absorbed into the tissues CO2 is the gas that represents respiratory acidosis, not O2.
pH = 7.29, PaCO2 = 47, HCO3 = 24 What is the problem? Compensated or Uncompensated?
pH = 7.29, PaCO2 = 47, HCO3 = 24 Step 1: Check the pH and determine if we have acidosis or alkalosis. The pH = 7.29, so we have ACIDOSIS. Step 2: What is causing acidosis? PaCO2 = 47, which is out of range on the ACID side. Therefore, we have RESPIRATORY ACIDOSIS. HCO3 = 24, which is in the normal range, so we do not have metabolic acidosis. Step 3: Do we have compensation? HCO3 is in the normal range, so it is NOT trying to compensate. Therefore, we have UNCOMPENSATED RESPIRATORY ACIDOSIS.
pH = 7.48, PaCO2 = 31, HCO3 = 20 What is the problem? Compensated or Uncompensated?
pH = 7.48, PaCO2 = 31, HCO3 = 20 Step 1: Check the pH and determine if we have acidosis or alkalosis. The pH = 7.48, so we have ALKALOSIS. Step 2: What is causing alkalosis? PaCO2 = 31, which is out of range on the BASIC side. Therefore, we have R ESPIRATORY ALKALOSIS. HCO3 = 20, which is out of range on the ACIDIC side. So we do not have metabolic acidosis. Step 3: Do we have compensation? HCO3 is trying to compensate for the respiratory alkalosis, but it hasn't gotten the pH back in normal range. Therefore we have PARTIALLY COMPENSATED RESPIRATORY ALKALOSIS.
