CH 27: ABGs Flashcards
pH range
7.35 - 7.45
PaO2 range
80-100 mmHg
SaO2 range
> 95%
PaCO2 range
35-45 mmHg
HCO3 range
22-26
In respiratory alkalosis, the pH is _____ and the PaCO2 is _____.
↑ ; ↓
In respiratory acidosis, the pH is _____ and the PaCO2 is _____.
↓ ; ↑
In metabolic alkalosis, the pH and HCO3- are _____ and the PaCO2 is _____ or normal.
↑ ; ↑
In metabolic acidosis, the pH and HCO3- are _____ and the PaCO2 is _____ or normal.
↓ ; ↓
A client’s arterial blood gas (ABG) results are: pH 7.30, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L. What is the correct interpretation of these results?
A. Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Respiratory alkalosis
B. Respiratory acidosis
Rationale: The pH is below the normal range (7.35–7.45), indicating acidosis. The PaCO2 is elevated (>45 mm Hg), which is consistent with respiratory acidosis. Bicarbonate (HCO3⁻) is within normal limits, so this is uncompensated respiratory acidosis.
A client’s ABG results are: pH 7.48, PaCO2 40 mm Hg, HCO3⁻ 30 mEq/L. What is the correct interpretation of these results?
A. Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic alkalosis
D. Combined respiratory and metabolic alkalosis
C. Metabolic alkalosis
Rationale: The pH is above the normal range, indicating alkalosis. The bicarbonate (HCO3⁻) is elevated, indicating metabolic alkalosis. PaCO2 is within normal limits, ruling out a respiratory cause.
A client with sepsis has ABG results of: pH 7.32, PaCO2 35 mm Hg, HCO3⁻ 18 mEq/L. What is the underlying condition?
A. Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Mixed acidosis
A. Metabolic acidosis
Rationale: The pH is low, indicating acidosis. The bicarbonate (HCO3⁻) is decreased (<22 mEq/L), confirming a metabolic cause. The PaCO2 is normal, ruling out a respiratory component.
A client’s ABG results are: pH 7.55, PaCO2 28 mm Hg, HCO3⁻ 24 mEq/L. What is the most likely cause of these results?
A. Prolonged vomiting
B. Hyperventilation
C. Diabetic ketoacidosis
D. Chronic obstructive pulmonary disease (COPD)
B. Hyperventilation
Rationale: The pH is elevated, indicating alkalosis. The PaCO2 is decreased (<35 mm Hg), consistent with respiratory alkalosis. This is often caused by hyperventilation.
Which ABG values are most consistent with partially compensated respiratory acidosis?
A. pH 7.38, PaCO2 48 mm Hg, HCO3⁻ 28 mEq/L
B. pH 7.30, PaCO2 50 mm Hg, HCO3⁻ 26 mEq/L
C. pH 7.34, PaCO2 52 mm Hg, HCO3⁻ 29 mEq/L
D. pH 7.50, PaCO2 30 mm Hg, HCO3⁻ 24 mEq/L
C. pH 7.34, PaCO2 52 mm Hg, HCO3⁻ 29 mEq/L
Rationale: The pH is low (indicating acidosis), and the elevated PaCO2 confirms a respiratory cause. The bicarbonate (HCO3⁻) is also elevated, showing partial metabolic compensation.
A client is admitted with ABG results of: pH 7.20, PaCO2 60 mm Hg, HCO3⁻ 26 mEq/L. What immediate action should the nurse anticipate?
A. Administering sodium bicarbonate
B. Initiating mechanical ventilation
C. Providing supplemental oxygen
D. Encouraging deep breathing and coughing
B. Initiating mechanical ventilation
Rationale: The pH and PaCO2 values indicate severe respiratory acidosis. Immediate intervention, such as mechanical ventilation, is required to improve gas exchange and lower PaCO2.
A client’s ABG results are: pH 7.40, PaCO2 40 mm Hg, HCO3⁻ 24 mEq/L, SaO2 88%. What should the nurse do first?
A. Administer supplemental oxygen
B. Notify the healthcare provider
C. Repeat the ABG test in 30 minutes
D. Document the findings as normal
A. Administer supplemental oxygen
Rationale: Although the pH, PaCO2, and HCO3⁻ are normal, the SaO2 is below the expected range (>95%). The priority is to improve oxygenation by administering supplemental oxygen.
A client’s ABG results are: pH 7.36, PaCO2 55 mm Hg, HCO3⁻ 32 mEq/L. What does this indicate?
A. Uncompensated respiratory acidosis
B. Fully compensated respiratory acidosis
C. Partially compensated metabolic alkalosis
D. Normal acid-base balance
B. Fully compensated respiratory acidosis
Rationale: The pH is within the normal range but on the acidic side, suggesting full compensation. The elevated PaCO2 indicates respiratory acidosis, and the elevated HCO3⁻ reflects renal compensation.
A client’s ABG results are: pH 7.31, PaCO2 50 mm Hg, HCO3⁻ 25 mEq/L, PaO2 75 mm Hg, SaO2 89%. Based on the 5-step process, what is the correct interpretation?
A. Uncompensated respiratory acidosis with hypoxemia
B. Partially compensated respiratory acidosis with normal oxygenation
C. Fully compensated respiratory acidosis with hypoxemia
D. Uncompensated metabolic acidosis with hypoxemia
A. Uncompensated respiratory acidosis with hypoxemia
Rationale: The pH is low, indicating acidosis. The PaCO2 is elevated, indicating a respiratory cause. HCO3⁻ is normal, showing no compensation. PaO2 and SaO2 are below normal, indicating hypoxemia.
A client’s ABG results are: pH 7.52, PaCO2 29 mm Hg, HCO3⁻ 24 mEq/L, PaO2 85 mm Hg, SaO2 96%. Using the ROME method, what is the underlying condition?
A. Respiratory alkalosis
B. Metabolic alkalosis
C. Fully compensated metabolic alkalosis
D. Combined metabolic and respiratory alkalosis
A. Respiratory alkalosis
Rationale: The pH is elevated, indicating alkalosis. The PaCO2 is decreased, consistent with a respiratory cause (respiratory opposite in ROME). HCO3⁻ is normal, indicating no metabolic involvement.
A client with renal failure has the following ABG results: pH 7.20, PaCO2 35 mm Hg, HCO3⁻ 15 mEq/L, PaO2 90 mm Hg, SaO2 98%. What is the most likely acid-base disturbance?
A. Uncompensated respiratory acidosis
B. Partially compensated metabolic acidosis
C. Uncompensated metabolic acidosis
D. Fully compensated metabolic acidosis
C. Uncompensated metabolic acidosis
Rationale: The pH is low, indicating acidosis. The HCO3⁻ is low, confirming a metabolic cause. The PaCO2 is normal, ruling out compensation or a respiratory component.
A client with pneumonia has ABG results: pH 7.36, PaCO2 48 mm Hg, HCO3⁻ 30 mEq/L, PaO2 68 mm Hg, SaO2 88%. What do these results indicate?
A. Fully compensated respiratory acidosis with hypoxemia
B. Partially compensated metabolic alkalosis with hypoxemia
C. Uncompensated respiratory acidosis with normal oxygenation
D. Fully compensated metabolic alkalosis with normal oxygenation
A. Fully compensated respiratory acidosis with hypoxemia
Rationale: The pH is normal but slightly acidic, indicating full compensation. The elevated PaCO2 and HCO3⁻ reflect respiratory acidosis with metabolic compensation. The low PaO2 and SaO2 indicate hypoxemia.
A client with prolonged vomiting presents with the following ABG results: pH 7.48, PaCO2 46 mm Hg, HCO3⁻ 30 mEq/L, PaO2 92 mm Hg, SaO2 97%. What is the correct interpretation?
A. Uncompensated respiratory alkalosis
B. Fully compensated metabolic alkalosis
C. Partially compensated metabolic alkalosis
D. Uncompensated metabolic alkalosis
C. Partially compensated metabolic alkalosis
Rationale: The pH is elevated, indicating alkalosis. The HCO3⁻ is elevated, confirming a metabolic cause. The PaCO2 is elevated, suggesting partial respiratory compensation.
A client’s ABG results are: pH 7.43, PaCO2 50 mm Hg, HCO3⁻ 30 mEq/L, PaO2 88 mm Hg, SaO2 90%. Using the 5-step process, how should the nurse interpret these results?
A. Fully compensated respiratory acidosis with normal oxygenation
B. Uncompensated metabolic alkalosis with normal oxygenation
C. Partially compensated respiratory alkalosis with hypoxemia
D. Fully compensated metabolic alkalosis with hypoxemia
D. Fully compensated metabolic alkalosis with hypoxemia
Rationale: The pH is normal but slightly alkaline, indicating full compensation. The HCO3⁻ is elevated, reflecting metabolic alkalosis, and the PaCO2 is elevated, indicating compensation. The low PaO2 and SaO2 indicate hypoxemia.
A client’s ABG results are: pH 7.30, PaCO2 60 mm Hg, HCO3⁻ 32 mEq/L, PaO2 55 mm Hg, SaO2 75%. What is the priority nursing intervention?
A. Administer sodium bicarbonate
B. Initiate oxygen therapy
C. Prepare for intubation and mechanical ventilation
D. Encourage the client to use an incentive spirometer
C. Prepare for intubation and mechanical ventilation
Rationale: The pH and elevated PaCO2 indicate respiratory acidosis with partial compensation. The PaO2 and SaO2 values indicate severe hypoxemia, necessitating immediate respiratory support such as intubation and ventilation.
A client with pneumonia is admitted with the following ABG results: pH 7.28, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L. What is the pathophysiology underlying the respiratory acidosis?
A. Alveolar hyperventilation causing CO2 retention
B. Decreased alveolar ventilation leading to CO2 retention
C. Increased renal excretion of bicarbonate
D. Excessive elimination of CO2
B. Decreased alveolar ventilation leading to CO2 retention
Rationale: Severe pneumonia can impair gas exchange and reduce alveolar ventilation, leading to CO2 retention and respiratory acidosis.
A client with Guillain-Barré syndrome develops progressive respiratory muscle weakness. Which ABG pattern is most concerning for this client?
A. pH 7.45, PaCO2 32 mm Hg, HCO3⁻ 22 mEq/L
B. pH 7.36, PaCO2 45 mm Hg, HCO3⁻ 25 mEq/L
C. pH 7.30, PaCO2 55 mm Hg, HCO3⁻ 24 mEq/L
D. pH 7.60, PaCO2 28 mm Hg, HCO3⁻ 20 mEq/L
C. pH 7.30, PaCO2 55 mm Hg, HCO3⁻ 24 mEq/L
Rationale: The low pH and elevated PaCO2 indicate uncompensated respiratory acidosis, which can occur due to respiratory muscle weakness and hypoventilation.
A client is admitted after a suspected sedative overdose. What initial ABG results would the nurse expect to see?
A. pH 7.52, PaCO2 28 mm Hg, HCO3⁻ 24 mEq/L
B. pH 7.28, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L
C. pH 7.38, PaCO2 40 mm Hg, HCO3⁻ 26 mEq/L
D. pH 7.48, PaCO2 35 mm Hg, HCO3⁻ 30 mEq/L
B. pH 7.28, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L
Rationale: Sedative overdose often causes respiratory depression, leading to hypoventilation, CO2 retention, and respiratory acidosis.
A client is diagnosed with pulmonary edema and has ABG results showing respiratory acidosis. What is the primary cause of the acidosis in this client?
A. Retention of bicarbonate by the kidneys
B. Impaired alveolar gas exchange
C. Excessive CO2 elimination
D. Decreased production of hydrogen ions
B. Impaired alveolar gas exchange
Rationale: Pulmonary edema causes fluid accumulation in the alveoli, impairing gas exchange and leading to CO2 retention, which causes respiratory acidosis.
A client with COPD presents with chronic respiratory acidosis. What compensatory mechanism would the nurse expect?
A. Increased bicarbonate excretion by the kidneys
B. Decreased renal hydrogen ion excretion
C. Decreased respiratory rate
D. Increased renal retention of bicarbonate
D. Increased renal retention of bicarbonate
Rationale: In chronic respiratory acidosis, the kidneys compensate by retaining bicarbonate to buffer the excess hydrogen ions caused by elevated PaCO2.
Which of the following clinical conditions is least likely to cause respiratory acidosis?
A. Atelectasis
B. Chronic obstructive pulmonary disease (COPD)
C. Hyperventilation due to anxiety
D. Mechanical hypoventilation
C. Hyperventilation due to anxiety
Rationale: Hyperventilation leads to excessive CO2 elimination and respiratory alkalosis, not acidosis. Atelectasis, COPD, and hypoventilation can all cause CO2 retention and respiratory acidosis.
A client with severe scoliosis is at risk for developing respiratory acidosis due to:
A. Reduced lung compliance and hypoventilation
B. Increased alveolar hyperventilation
C. Excessive use of accessory muscles for breathing
D. Elevated PaO2 levels impairing gas exchange
A. Reduced lung compliance and hypoventilation
Rationale: Severe scoliosis can restrict lung expansion, reduce compliance, and impair ventilation, leading to CO2 retention and respiratory acidosis.
A client presents with lightheadedness, dizziness, and tachypnea following an anxiety attack. ABG results are: pH 7.50, PaCO2 30 mm Hg, HCO3⁻ 24 mEq/L. What is the correct interpretation of these findings?
A. Uncompensated respiratory alkalosis
B. Uncompensated metabolic alkalosis
C. Partially compensated respiratory alkalosis
D. Fully compensated respiratory alkalosis
A. Uncompensated respiratory alkalosis
Rationale: The elevated pH and decreased PaCO2 indicate respiratory alkalosis. The normal HCO3⁻ indicates no compensation. This is commonly seen in anxiety-induced hyperventilation.
A nurse is caring for a client with liver failure who is breathing rapidly. The nurse anticipates which ABG result consistent with respiratory alkalosis?
A. pH 7.32, PaCO2 48 mm Hg, HCO3⁻ 26 mEq/L
B. pH 7.46, PaCO2 32 mm Hg, HCO3⁻ 23 mEq/L
C. pH 7.36, PaCO2 40 mm Hg, HCO3⁻ 24 mEq/L
D. pH 7.20, PaCO2 55 mm Hg, HCO3⁻ 22 mEq/L
B. pH 7.46, PaCO2 32 mm Hg, HCO3⁻ 23 mEq/L
Rationale: The elevated pH and low PaCO2 indicate respiratory alkalosis, which can result from hyperventilation due to liver failure. The normal HCO3⁻ indicates no compensation.
A client with a recent stroke is hyperventilating and has ABG results showing respiratory alkalosis. What physiological mechanism explains this finding?
A. Increased renal retention of bicarbonate
B. Stimulated respiratory center in the brainstem
C. Increased alveolar CO2 production
D. Decreased oxygen demand at the tissue level
B. Stimulated respiratory center in the brainstem
Rationale: Conditions like stroke can stimulate the respiratory center, leading to hyperventilation and excessive CO2 elimination, which causes respiratory alkalosis.
A client with a fever and septicemia is admitted to the ICU. Which ABG pattern would the nurse expect due to hyperventilation caused by the fever?
A. pH 7.30, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L
B. pH 7.50, PaCO2 28 mm Hg, HCO3⁻ 22 mEq/L
C. pH 7.35, PaCO2 40 mm Hg, HCO3⁻ 24 mEq/L
D. pH 7.20, PaCO2 60 mm Hg, HCO3⁻ 26 mEq/L
B. pH 7.50, PaCO2 28 mm Hg, HCO3⁻ 22 mEq/L
A client is admitted for salicylate poisoning. The nurse notes ABG results of pH 7.48, PaCO2 28 mm Hg, HCO3⁻ 22 mEq/L. Which nursing intervention is most appropriate?
A. Administer IV sodium bicarbonate
B. Encourage deep breathing exercises
C. Administer activated charcoal as prescribed
D. Decrease oxygen flow rate
C. Administer activated charcoal as prescribed
A client with diabetic ketoacidosis (DKA) presents with the following ABG results: pH 7.30, PaCO2 36 mm Hg, HCO3⁻ 18 mEq/L. Which physiological process is responsible for the development of metabolic acidosis in this condition?
A. Excessive CO2 retention due to hypoventilation
B. Increased production of ketones as an alternative energy source
C. Excessive renal bicarbonate retention
D. Increased lactate production secondary to tissue hypoxia
B. Increased production of ketones as an alternative energy source
Rationale: In DKA, the body breaks down fats for energy due to a lack of insulin, leading to the production of ketones, which are acidic and result in metabolic acidosis.
A client is admitted with chronic diarrhea and metabolic acidosis. Which laboratory finding is consistent with this condition?
A. Elevated serum bicarbonate
B. Decreased anion gap
C. Decreased serum bicarbonate
D. Increased PaCO2
C. Decreased serum bicarbonate
Rationale: Chronic diarrhea causes a loss of bicarbonate, resulting in metabolic acidosis. The serum bicarbonate level will be reduced in this condition.
A nurse is caring for a client with lactic acidosis secondary to shock. What is the primary cause of lactic acid buildup in this condition?
A. Hypoxia-induced anaerobic metabolism
B. Excessive production of ketone bodies
C. Impaired excretion of hydrogen ions by the kidneys
D. Increased loss of bicarbonate through the GI tract
A. Hypoxia-induced anaerobic metabolism
Rationale: In shock, tissue hypoxia leads to anaerobic metabolism, which results in the production and accumulation of lactic acid, causing metabolic acidosis.
A client with renal failure has ABG results indicating metabolic acidosis. What is the underlying pathophysiology for this condition?
A. Decreased hydrogen ion excretion and impaired bicarbonate reabsorption
B. Excessive ketone production from fat metabolism
C. Increased gastrointestinal loss of bicarbonate
D. Prolonged hypoxia resulting in lactate accumulation
A. Decreased hydrogen ion excretion and impaired bicarbonate reabsorption
Rationale: In renal failure, the kidneys are unable to excrete hydrogen ions or reabsorb bicarbonate efficiently, leading to metabolic acidosis.
A client with starvation is admitted with metabolic acidosis. Which assessment finding supports this diagnosis?
A. Increased blood glucose levels
B. Presence of ketones in the urine
C. Decreased respiratory rate
D. Elevated serum bicarbonate levels
B. Presence of ketones in the urine
Rationale: Starvation causes the body to break down fats for energy, leading to the production of ketones. The resulting ketoacidosis contributes to metabolic acidosis.
A client is diagnosed with a GI fistula and metabolic acidosis. What is the most likely cause of the acidosis?
A. Decreased reabsorption of hydrogen ions
B. Excessive retention of carbon dioxide
C. Increased lactic acid production from tissue hypoxia
D. Increased loss of bicarbonate through GI secretions
D. Increased loss of bicarbonate through GI secretions
Rationale: GI fistulas can result in the loss of bicarbonate-rich fluids, particularly from the intestines, leading to metabolic acidosis.
A nurse is reviewing ABG results for a client with shock. The values are: pH 7.25, PaCO2 38 mm Hg, HCO3⁻ 16 mEq/L. What is the body’s compensatory mechanism for this acid-base imbalance?
A. Increased renal excretion of hydrogen ions
B. Increased respiratory rate to eliminate CO2
C. Decreased renal production of bicarbonate
D. Decreased respiratory rate to retain CO2
B. Increased respiratory rate to eliminate CO2
Rationale: In metabolic acidosis, the body compensates by increasing respiratory rate (Kussmaul respirations) to eliminate CO2 and reduce acidity.
A client is admitted with metabolic alkalosis from excessive bicarbonate ingestion. Which nursing intervention is most appropriate to correct the underlying cause?
A. Administer sodium bicarbonate to neutralize gastric acid
B. Infuse IV potassium chloride to replace deficits
C. Monitor and treat for fluid volume deficit
D. Educate the client on limiting antacid use
D. Educate the client on limiting antacid use
Rationale: Excessive bicarbonate ingestion (e.g., from antacids) is a common cause of metabolic alkalosis. Education on proper antacid use addresses the underlying issue.
A client has been taking a loop diuretic for congestive heart failure and is diagnosed with metabolic alkalosis. What is the primary cause of the acid-base imbalance in this client?
A. Excessive loss of hydrogen ions through the kidneys
B. Increased production of bicarbonate by the kidneys
C. Impaired excretion of carbon dioxide
D. Excessive loss of bicarbonate through the GI tract
A. Excessive loss of hydrogen ions through the kidneys
Rationale: Loop diuretics promote the excretion of hydrogen ions and potassium in the urine, leading to a loss of acid and the development of metabolic alkalosis.
A nurse is caring for a client with prolonged vomiting. The client’s ABG results are: pH 7.48, PaCO2 45 mm Hg, HCO3⁻ 30 mEq/L. What is the correct interpretation of these findings?
A. Uncompensated metabolic alkalosis
B. Partially compensated metabolic alkalosis
C. Uncompensated respiratory alkalosis
D. Fully compensated metabolic alkalosis
A. Uncompensated metabolic alkalosis
Rationale: Elevated pH and HCO3⁻ with normal PaCO2 indicate metabolic alkalosis without compensation. Vomiting leads to the loss of hydrogen ions, contributing to alkalosis.
A client receiving NG suctioning for several days develops metabolic alkalosis. What is the likely cause of this acid-base imbalance?
A. Loss of bicarbonate-rich pancreatic secretions
B. Excessive retention of carbon dioxide
C. Loss of gastric acid through suctioning
D. Increased hydrogen ion excretion by the kidneys
C. Loss of gastric acid through suctioning
Rationale: NG suctioning removes hydrochloric acid from the stomach, decreasing the body’s hydrogen ion concentration and leading to metabolic alkalosis.
A client with mineralocorticoid excess is diagnosed with metabolic alkalosis. Which electrolyte imbalance is most likely to accompany this condition?
A. Hyperkalemia
B. Hypokalemia
C. Hypercalcemia
D. Hyponatremia
B. Hypokalemia
Rationale: Mineralocorticoid excess (e.g., from conditions like hyperaldosteronism) promotes renal excretion of potassium and hydrogen ions, resulting in hypokalemia and metabolic alkalosis.
A client with chronic hypokalemia is admitted to the hospital. ABG results show: pH 7.50, PaCO2 46 mm Hg, HCO3⁻ 28 mEq/L. Which clinical finding supports the diagnosis of metabolic alkalosis?
A. Muscle weakness and decreased deep tendon reflexes
B. Kussmaul respirations and warm, flushed skin
C. Increased respiratory rate and decreased urine output
D. Cyanosis and peripheral edema
A. Muscle weakness and decreased deep tendon reflexes
Rationale: Metabolic alkalosis and hypokalemia are often associated. Hypokalemia causes muscle weakness and reduced reflexes, while metabolic alkalosis itself can cause neuromuscular excitability.
A nurse reviews the ABG values: pH 7.45, PaCO2 50 mm Hg, HCO3⁻ 30 mEq/L. What condition is indicated?
A. Fully compensated metabolic alkalosis
B. Fully compensated respiratory acidosis
C. Partially compensated metabolic alkalosis
D. Fully compensated respiratory alkalosis
A. Fully compensated metabolic alkalosis
Rationale: The normal pH is slightly alkalotic. Elevated HCO3⁻ indicates metabolic alkalosis. The high PaCO2 reflects respiratory compensation.
A client with renal failure has the following ABG results: pH 7.18, PaCO2 32 mm Hg, HCO3⁻ 15 mEq/L. How should the nurse interpret these values?
A. Fully compensated metabolic acidosis
B. Uncompensated respiratory acidosis
C. Partially compensated metabolic acidosis
D. Uncompensated metabolic acidosis
C. Partially compensated metabolic acidosis
Rationale: The low pH and low HCO3⁻ indicate metabolic acidosis. Low PaCO2 reflects respiratory compensation, though it has not fully normalized the pH.
A nurse is assessing ABG values: pH 7.50, PaCO2 25 mm Hg, HCO3⁻ 24 mEq/L. Which condition is indicated by these findings?
A. Uncompensated metabolic alkalosis
B. Uncompensated respiratory alkalosis
C. Fully compensated respiratory alkalosis
D. Partially compensated respiratory alkalosis
B. Uncompensated respiratory alkalosis
Rationale: The elevated pH indicates alkalosis. The low PaCO2 points to a respiratory origin. Normal HCO3⁻ suggests no metabolic compensation.
A client’s ABG values are as follows: pH 7.44, PaCO2 30 mm Hg, HCO3⁻ 20 mEq/L. What do these results suggest?
A. Fully compensated respiratory alkalosis
B. Fully compensated metabolic acidosis
C. Partially compensated respiratory alkalosis
D. Fully compensated respiratory acidosis
A. Fully compensated respiratory alkalosis
Rationale: The normal pH is slightly alkalotic. Low PaCO2 indicates respiratory alkalosis, and the low HCO3⁻ shows compensation by the kidneys.
A client’s ABG results show: pH 7.32, PaCO2 48 mm Hg, HCO3⁻ 28 mEq/L. What is the correct interpretation?
A. Uncompensated metabolic acidosis
B. Partially compensated respiratory acidosis
C. Uncompensated respiratory acidosis
D. Fully compensated respiratory acidosis
B. Partially compensated respiratory acidosis
Rationale: The low pH indicates acidosis. The elevated PaCO2 points to a respiratory cause. Elevated HCO3⁻ indicates the kidneys are attempting to compensate.
A client presents with ABG values: pH 7.58, PaCO2 45 mm Hg, HCO3⁻ 35 mEq/L. Which condition do these findings indicate?
A. Uncompensated metabolic alkalosis
B. Partially compensated metabolic alkalosis
C. Fully compensated metabolic alkalosis
D. Uncompensated respiratory alkalosis
A. Uncompensated metabolic alkalosis
Rationale: The elevated pH and HCO3⁻ point to metabolic alkalosis. A normal PaCO2 shows no respiratory compensation.
A client in shock has ABG results of: pH 7.20, PaCO2 38 mm Hg, HCO3⁻ 15 mEq/L. What is the correct interpretation of these results?
A. Uncompensated metabolic acidosis
B. Uncompensated respiratory acidosis
C. Partially compensated metabolic acidosis
D. Fully compensated metabolic acidosis
A. Uncompensated metabolic acidosis
Rationale: The low pH and low HCO3⁻ point to metabolic acidosis. Normal PaCO2 indicates no respiratory compensation.
ABG results for a client are as follows: pH 7.47, PaCO2 32 mm Hg, HCO3⁻ 22 mEq/L. What is the likely condition?
A. Partially compensated metabolic alkalosis
B. Uncompensated metabolic alkalosis
C. Uncompensated respiratory alkalosis
D. Uncompensated respiratory acidosis
C. Uncompensated respiratory alkalosis
Rationale: The elevated pH indicates alkalosis. Low PaCO2 indicates respiratory origin. Normal HCO3⁻ suggests no metabolic compensation.
A nurse reviews ABG results: pH 7.38, PaCO2 48 mm Hg, HCO3⁻ 30 mEq/L. What do these values indicate?
A. Uncompensated respiratory alkalosis
B. Fully compensated respiratory acidosis
C. Fully compensated metabolic alkalosis
D. Partially compensated respiratory acidosis
B. Fully compensated respiratory acidosis
Rationale: The pH is normal but slightly acidic, PaCO2 is high (indicating acidosis), and HCO3⁻ is elevated, showing compensation. Full compensation is indicated by the normal pH.
A client’s ABG results are as follows: pH 7.25, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L. What is the correct interpretation of this ABG?
A. Uncompensated respiratory acidosis
B. Partially compensated respiratory acidosis
C. Uncompensated metabolic acidosis
D. Fully compensated respiratory acidosis
A. Uncompensated respiratory acidosis
Rationale: The low pH indicates acidosis. The elevated PaCO2 points to a respiratory origin. Normal HCO3⁻ levels indicate no compensation has occurred.
A patient who was involved in a motor vehicle crash has had a tracheostomy placed to allow for continued mechanical ventilation. How would the nurse interpret the following arterial blood gas results: pH 7.48, PaO 2 85 mm Hg, PaCO 2 32 mm Hg, and HCO 3 25 mEq/L?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis
d. Respiratory alkalosis
Rationale: The pH indicates that the patient has alkalosis and the low PaCO2 indicates a respiratory cause. The other responses are incorrect based on the pH and the normal HCO3 .
A patient who is lethargic with deep, rapid respirations has the following arterial blood gas (ABG) results: pH 7.32, PaO2 88 mm Hg, PaCO2 35 mm Hg, and HCO3 16 mEq/L. How would the nurse interpret these results?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis
a. Metabolic acidosis
Rationale: The pH and HCO3 indicate the patient has a metabolic acidosis. The ABGs are inconsistent with the other responses.
A 68-year-old male with a history of COPD is admitted to the ICU with increasing shortness of breath and confusion. His respiratory rate is 8 breaths per minute, and his oxygen saturation is 84% on room air. An ABG is obtained, revealing the following values:
* pH: 7.28
* PaCO2: 60 mmHg
* HCO3-: 26 mEq/L
* PaO2: 55 mmHg
Which intervention should the nurse anticipate implementing first?
A. Administering sodium bicarbonate IV
B. Initiating non-invasive positive pressure ventilation (NIPPV)
C. Increasing the patient’s oxygen to 6 L/min via nasal cannula
D. Encouraging the patient to use an incentive spirometer
B. Initiating non-invasive positive pressure ventilation (NIPPV)
Rationale: The ABG values indicate respiratory acidosis with hypoxemia, likely due to ventilatory failure from COPD exacerbation. The high PaCO2 (60 mmHg) and low pH (7.28) show CO2 retention, while the HCO3- is within normal limits, indicating an uncompensated respiratory acidosis. NIPPV, such as BiPAP, helps improve ventilation by reducing CO2 retention and improving oxygenation. Sodium bicarbonate is not indicated because the primary issue is respiratory, not metabolic. Increasing oxygen without ventilatory support can suppress the patient’s hypoxic drive, worsening CO2 retention. Incentive spirometry is useful for atelectasis prevention but is not the priority in this scenario.
A 52-year-old patient with acute respiratory distress syndrome (ARDS) is intubated and on mechanical ventilation. The patient’s ABG results are:
* pH: 7.51
* PaCO2: 28 mmHg
* HCO3-: 24 mEq/L
* PaO2: 60 mmHg
Which ventilator adjustment should the nurse anticipate?
A. Increase the tidal volume
B. Increase the respiratory rate
C. Decrease the fraction of inspired oxygen (FiO2)
D. Decrease the respiratory rate
D. Decrease the respiratory rate
Rationale: The ABG results indicate respiratory alkalosis (high pH, low PaCO2), likely due to hyperventilation caused by a high ventilatory rate. To correct this, the respiratory rate should be decreased to allow CO2 levels to rise and restore acid-base balance. Increasing the tidal volume or respiratory rate would worsen alkalosis by further lowering PaCO2. Decreasing FiO2 is an oxygenation-related adjustment but does not directly address respiratory alkalosis.
A nurse is reviewing ABG results for a patient who is experiencing metabolic acidosis. Which findings support this diagnosis? (Select all that apply.)
A. pH 7.30
B. HCO3- 18 mEq/L
C. PaCO2 55 mmHg
D. PaO2 98 mmHg
E. pH 7.49
F. HCO3- 30 mEq/L
A. pH 7.30
B. HCO3- 18 mEq/L
Rationale:
* A pH of 7.30 is lower than normal (7.35–7.45), indicating acidosis.
* A HCO3- of 18 mEq/L is below the normal range (22–26 mEq/L), confirming metabolic acidosis.
* PaCO2 of 55 mmHg suggests respiratory acidosis, not metabolic acidosis.
* PaO2 of 98 mmHg is within the normal range and does not indicate acid-base disturbance.
* A pH of 7.49 indicates alkalosis, not acidosis.
* HCO3- of 30 mEq/L is elevated, suggesting metabolic alkalosis.
A patient is admitted with diabetic ketoacidosis (DKA). Which ABG results would the nurse expect?
A. pH 7.30, PaCO2 50 mmHg, HCO3- 30 mEq/L
B. pH 7.48, PaCO2 30 mmHg, HCO3- 25 mEq/L
C. pH 7.25, PaCO2 34 mmHg, HCO3- 15 mEq/L
D. pH 7.50, PaCO2 50 mmHg, HCO3- 30 mEq/L
C. pH 7.25, PaCO2 34 mmHg, HCO3- 15 mEq/L
Rationale: Diabetic ketoacidosis (DKA) causes metabolic acidosis due to excessive ketone production. Expected ABG findings include:
* Low pH (<7.35), indicating acidosis
* Low HCO3- (<22 mEq/L), confirming metabolic acidosis
* PaCO2 may be normal or low as the body compensates with Kussmaul respirations (deep, rapid breathing) to eliminate CO2.
Option A represents respiratory acidosis with metabolic alkalosis, option B represents respiratory alkalosis, and option D represents metabolic alkalosis with respiratory acidosis, none of which are consistent with DKA.
A 68-year-old patient with chronic obstructive pulmonary disease (COPD) is admitted with worsening respiratory distress. The healthcare provider orders continuous end-tidal CO₂ (PetCO₂) monitoring. The nurse observes a sudden decrease in the PetCO₂ reading. Which of the following conditions is the most likely cause of this finding?
A. Pulmonary embolism
B. Respiratory depression due to opioid administration
C. Hyperventilation
D. Bronchospasm
A. Pulmonary embolism
Rationale: A sudden decrease in PetCO₂ indicates a decrease in CO₂ delivery to the lungs, which can occur with a pulmonary embolism due to obstruction of pulmonary blood flow. This reduces perfusion to ventilated alveoli, leading to a drop in PetCO₂.
A nurse is caring for a ventilated patient in the ICU. Capnography shows a PetCO₂ of 55 mmHg, and the waveform remains elevated throughout exhalation. The patient is also showing signs of lethargy and confusion. What is the best nursing action?
A. Increase the ventilator rate to improve CO₂ elimination
B. Administer a bronchodilator as prescribed
C. Check the patient’s bicarbonate level
D. Decrease FiO₂ to avoid oxygen toxicity
A. Increase the ventilator rate to improve CO₂ elimination
Rationale: A PetCO₂ of 55 mmHg indicates hypercapnia (elevated CO₂ levels), which can cause lethargy and confusion. Increasing the ventilator rate enhances CO₂ removal, improving gas exchange and preventing respiratory acidosis.
The nurse is teaching a respiratory therapy student about capnography monitoring. Which of the following statements about PetCO₂ are correct? (SATA)
A. PetCO₂ reflects changes in ventilation more rapidly than pulse oximetry.
B. A sudden increase in PetCO₂ may indicate hypoventilation.
C. PetCO₂ values are typically 10–15 mmHg higher than PaCO₂.
D. Capnography waveforms provide information about airway resistance.
E. PetCO₂ monitoring is useful in cardiac arrest to assess the effectiveness of CPR.
A. PetCO₂ reflects changes in ventilation more rapidly than pulse oximetry.
B. A sudden increase in PetCO₂ may indicate hypoventilation.
D. Capnography waveforms provide information about airway resistance.
E. PetCO₂ monitoring is useful in cardiac arrest to assess the effectiveness of CPR.
Rationale:
* A: Capnography reflects ventilation changes faster than pulse oximetry because it detects CO₂ levels directly.
* B: Hypoventilation leads to CO₂ retention, increasing PetCO₂.
* D: Changes in the shape of capnography waveforms indicate airway resistance (e.g., bronchospasm).
* E: In cardiac arrest, effective chest compressions improve circulation and CO₂ elimination, making PetCO₂ monitoring useful in assessing CPR effectiveness.
The nurse is monitoring a postoperative patient using a nasal cannula with a sidestream capnometer. The PetCO₂ value has dropped from 38 mmHg to 22 mmHg. What is the most appropriate action?
A. Assess for signs of airway obstruction
B. Increase the oxygen flow rate
C. Encourage the patient to take slow, deep breaths
D. Check the placement of the nasal cannula
D. Check the placement of the nasal cannula
Rationale: A drop in PetCO₂ may indicate an issue with the sampling system. In patients using a sidestream capnometer, a displaced nasal cannula can result in inaccurate readings. Ensuring proper placement helps obtain an accurate measurement.
A 45-year-old patient is being monitored with transcutaneous CO₂ (PtCO₂) due to respiratory failure. The nurse notes that the PtCO₂ reading is significantly higher than the PaCO₂ obtained from an arterial blood gas (ABG). What is the best explanation for this discrepancy?
A. The patient is in metabolic acidosis
B. The sensor has been left in place for too long without recalibration
C. PtCO₂ readings are less accurate in hypoperfused states
D. The arterial blood gas sample was likely contaminated
C. PtCO₂ readings are less accurate in hypoperfused states
Rationale: Transcutaneous CO₂ measurements rely on capillary blood flow. In conditions such as shock or poor peripheral perfusion, PtCO₂ may be falsely elevated compared to PaCO₂ because of impaired CO₂ diffusion through the skin.
A patient in the ICU is receiving mechanical ventilation. The capnography waveform shows a sudden loss of PetCO₂ (flatline). Which of the following is the most urgent concern?
A. Accidental endotracheal tube dislodgement
B. Increased airway resistance
C. Bronchospasm
D. Hyperventilation
A. Accidental endotracheal tube dislodgement
Rationale: A sudden loss of PetCO₂ (flatline waveform) suggests that CO₂ is no longer being exhaled, which can indicate accidental extubation, a ventilator disconnection, or equipment failure. This is a life-threatening emergency requiring immediate assessment of the airway.
A nurse is reviewing capnography monitoring with a group of student nurses. Which of the following factors can cause an increase in PetCO₂? (SATA)
A. Hypoventilation
B. Fever
C. Pulmonary embolism
D. Increased metabolic rate
E. Cardiac arrest
A. Hypoventilation
B. Fever
D. Increased metabolic rate
Rationale:
* A: Hypoventilation leads to CO₂ retention, raising PetCO₂.
* B: Fever increases metabolism, producing more CO₂.
* D: A higher metabolic rate generates more CO₂, increasing PetCO₂.
Pulmonary embolism (C) and cardiac arrest (E) reduce perfusion, leading to a decrease in PetCO₂.
A patient is on continuous capnography monitoring after extubation. The nurse observes a gradual increase in PetCO₂ from 37 mmHg to 52 mmHg over 30 minutes. What is the best intervention?
A. Encourage the patient to cough and deep breathe
B. Increase the patient’s oxygen flow rate
C. Prepare for possible reintubation
D. Reposition the CO₂ sensor
C. Prepare for possible reintubation
Rationale: A rising PetCO₂ indicates worsening hypoventilation and possible respiratory failure. This is an early sign that the patient may require reintubation if they cannot maintain adequate ventilation.
A 56-year-old patient with sepsis is in the ICU. The nurse notes that the patient’s ScvO₂ is 88%, and they are receiving mechanical ventilation with an FiO₂ of 60%. Which of the following is the most likely explanation for this finding?
A. The patient has increased oxygen demand due to fever
B. The patient is experiencing tissue hypoxia due to impaired oxygen utilization
C. The patient has undiagnosed anemia
D. The pulmonary artery catheter is malpositioned
B. The patient is experiencing tissue hypoxia due to impaired oxygen utilization
Rationale: Sepsis can impair cellular oxygen utilization, leading to a falsely high ScvO₂ despite tissue hypoxia. The inability of tissues to extract oxygen results in elevated venous oxygen saturation.
A nurse is monitoring a patient post-cardiac surgery. The patient’s SvO₂ has dropped from 70% to 55% over the past hour. Which of the following interventions should the nurse prioritize?
A. Increase the patient’s oxygen delivery
B. Assess for signs of bleeding or hypovolemia
C. Decrease ventilatory support to reduce oxygen supply
D. Encourage ambulation to improve circulation
B. Assess for signs of bleeding or hypovolemia
Rationale: A drop in SvO₂ suggests decreased oxygen delivery, which can result from low cardiac output, hypovolemia, or anemia. The nurse should assess for signs of bleeding or fluid loss as a priority.
A patient has an SvO₂ of 58%. The nurse understands that which of the following conditions could be causing this finding? (SATA)
A. Anemia
B. Cardiogenic shock
C. Hypothermia
D. Seizures
E. Pulmonary embolism
A. Anemia
B. Cardiogenic shock
D. Seizures
E. Pulmonary embolism
Rationale:
* A (Anemia): Low hemoglobin reduces oxygen transport, lowering SvO₂.
* B (Cardiogenic shock): Low cardiac output leads to decreased oxygen delivery.
* D (Seizures): Increased metabolic demand raises oxygen consumption.
* E (Pulmonary embolism): Decreased perfusion leads to lower oxygen delivery.
C (Hypothermia) would increase SvO₂ by decreasing metabolic demand.
A patient with severe heart failure has an SvO₂ of 50%. The nurse should anticipate which of the following findings?
A. Decreased cardiac output and tissue hypoxia
B. Increased oxygen delivery and hyperoxia
C. Normal oxygen extraction and metabolic balance
D. Increased hemoglobin levels compensating for low perfusion
A. Decreased cardiac output and tissue hypoxia
Rationale: Low SvO₂ (<60%) often indicates decreased cardiac output, leading to poor tissue oxygenation and increased oxygen extraction by the tissues.
A trauma patient in the emergency department is experiencing hemorrhagic shock. Their ScvO₂ is 50%, and SaO₂ is 90%. What does this indicate?
A. The patient has excessive oxygen delivery
B. The patient is in septic shock with impaired oxygen utilization
C. The patient’s oxygen saturation is falsely elevated
D. The patient is experiencing increased oxygen consumption due to shock
D. The patient is experiencing increased oxygen consumption due to shock
Rationale: Low ScvO₂ suggests poor oxygen delivery due to hypovolemia and increased tissue oxygen extraction, common in hemorrhagic shock.
A nurse is evaluating a mechanically ventilated patient with a high SvO₂ of 94%. Which condition is most likely responsible for this value?
A. Fever
B. Cardiogenic shock
C. Sepsis
D. Pulmonary edema
C. Sepsis
Rationale: In sepsis, cells lose the ability to extract oxygen efficiently, resulting in high SvO₂ despite tissue hypoxia.
The nurse is reviewing factors that can lead to a high SvO₂ (above 80%). Which of the following conditions can cause this? (SATA)
A. Sedation
B. Anemia
C. Hypothermia
D. Increased cardiac output
E. Sepsis
A. Sedation
C. Hypothermia
D. Increased cardiac output
E. Sepsis
Rationale:
* A (Sedation) and C (Hypothermia): Reduce metabolic demand, decreasing oxygen consumption.
* D (Increased cardiac output): May provide excess oxygen supply.
* E (Sepsis): Impaired oxygen extraction by tissues raises SvO₂.
Anemia (B) would lower SvO₂ due to reduced oxygen transport.
A patient with pneumonia has an ScvO₂ of 55% despite receiving oxygen therapy. Which of the following interventions would most effectively improve this value?
A. Increase IV fluid administration
B. Increase ventilator FiO₂ settings
C. Administer a blood transfusion
D. Suction the patient’s airway
C. Administer a blood transfusion
Rationale: A low ScvO₂ can be due to anemia or decreased oxygen delivery. A blood transfusion improves oxygen-carrying capacity, increasing ScvO₂.
A patient in the ICU has a SvO₂ of 78% and appears hemodynamically stable. What does this value most likely indicate?
A. The patient has adequate oxygen supply and demand balance
B. The patient is experiencing worsening heart failure
C. The patient is in a hypermetabolic state
D. The patient may be experiencing undiagnosed bleeding
A. The patient has adequate oxygen supply and demand balance
Rationale: A normal SvO₂ (60%-80%) suggests a balance between oxygen delivery and demand, indicating stable hemodynamics.
A critically ill patient has a SvO₂ of 85%. Which of the following findings might support this measurement? (SATA)
A. The patient is receiving neuromuscular blockade
B. The patient is febrile with a heart rate of 120 bpm
C. The patient has severe sepsis
D. The patient has a hemoglobin level of 7 g/dL
E. The patient is receiving high doses of sedation
A. The patient is receiving neuromuscular blockade
C. The patient has severe sepsis
E. The patient is receiving high doses of sedation
Rationale:
* A (Neuromuscular blockade): Decreases muscle activity, reducing oxygen demand.
* C (Sepsis): Causes impaired oxygen extraction.
* E (Sedation): Lowers metabolic rate, decreasing oxygen consumption.
Fever (B) and anemia (D) decrease SvO₂ by increasing oxygen demand.
A nurse is monitoring SvO₂ trends in a postoperative patient. Which trend would most concern the nurse?
A. SvO₂ decreasing from 78% to 72%
B. SvO₂ increasing from 75% to 90%
C. SvO₂ stabilizing at 65%
D. SvO₂ fluctuating between 60% and 80% over 6 hours
B. SvO₂ increasing from 75% to 90%
Rationale: A rising SvO₂ may indicate impaired oxygen extraction, commonly seen in sepsis or impending shock.
A 68-year-old patient with COPD is admitted to the emergency department with increasing dyspnea and confusion. Arterial blood gas (ABG) results are as follows:
* pH: 7.30
* PaCO₂: 60 mmHg
* HCO₃⁻: 28 mEq/L
What is the most likely acid-base imbalance present in this patient?
A. Uncompensated metabolic acidosis
B. Fully compensated respiratory acidosis
C. Partially compensated respiratory acidosis
D. Uncompensated respiratory alkalosis
C. Partially compensated respiratory acidosis
Rationale: The low pH (<7.35) and high PaCO₂ (>45 mmHg) indicate respiratory acidosis. The slightly elevated HCO₃⁻ suggests partial compensation by the kidneys, but since the pH is still abnormal, it is not fully compensated.
A nurse is caring for a patient with diabetic ketoacidosis (DKA). The patient’s ABG results are:
* pH: 7.25
* PaCO₂: 32 mmHg
* HCO₃⁻: 15 mEq/L
Which compensatory mechanism is most likely occurring?
A. The kidneys are increasing bicarbonate excretion
B. The lungs are increasing CO₂ retention
C. The lungs are increasing the respiratory rate
D. The kidneys are decreasing bicarbonate reabsorption
C. The lungs are increasing the respiratory rate
Rationale: The low pH and low HCO₃⁻ indicate metabolic acidosis. The low PaCO₂ suggests respiratory compensation through hyperventilation (Kussmaul respirations), which helps eliminate CO₂ to increase pH.
A patient with chronic kidney disease (CKD) presents with metabolic acidosis. Which of the following are potential causes of this condition? (SATA)
A. Decreased hydrogen ion excretion
B. Loss of bicarbonate through diarrhea
C. Increased ketone production
D. Excessive vomiting
E. Retention of acid waste products
A. Decreased hydrogen ion excretion
B. Loss of bicarbonate through diarrhea
C. Increased ketone production
E. Retention of acid waste products
Rationale:
* A (Decreased hydrogen ion excretion): CKD impairs the kidneys’ ability to excrete H⁺, leading to acidosis.
* B (Loss of bicarbonate through diarrhea): Loss of HCO₃⁻ causes metabolic acidosis.
* C (Increased ketone production): Ketoacidosis (e.g., in diabetes) lowers pH.
* E (Retention of acid waste products): In CKD, nitrogenous wastes accumulate, worsening acidosis.
D (Excessive vomiting) leads to metabolic alkalosis, not acidosis.
A postoperative patient is receiving nasogastric (NG) suction for gastric decompression. The nurse notices muscle cramps and irritability. ABG results show:
* pH: 7.50
* PaCO₂: 45 mmHg
* HCO₃⁻: 30 mEq/L
Which of the following interventions is most appropriate?
A. Discontinue the NG tube suction
B. Administer IV sodium bicarbonate
C. Encourage deep, rapid breathing
D. Prepare the patient for mechanical ventilation
A. Discontinue the NG tube suction
Rationale: High pH and high HCO₃⁻ indicate metabolic alkalosis, which can result from excessive loss of gastric acid (e.g., from prolonged NG suctioning). Stopping suction can prevent further alkalosis.
A patient experiencing a panic attack arrives at the emergency department. The patient is hyperventilating and complains of dizziness and tingling in their hands. ABG results are:
* pH: 7.48
* PaCO₂: 30 mmHg
* HCO₃⁻: 24 mEq/L
Which nursing intervention is the priority?
A. Administer sodium bicarbonate
B. Have the patient breathe into a paper bag
C. Increase the oxygen flow rate
D. Initiate rapid intubation
B. Have the patient breathe into a paper bag
Rationale: The high pH and low PaCO₂ indicate respiratory alkalosis, caused by hyperventilation. Breathing into a paper bag helps retain CO₂ and correct alkalosis.
A nurse is caring for a patient with respiratory acidosis. Which of the following conditions could be a cause of this imbalance? (SATA)
A. Opioid overdose
B. Pneumonia
C. Pulmonary embolism
D. Chronic obstructive pulmonary disease
E. Excessive nasogastric suctioning
A. Opioid overdose
B. Pneumonia
D. Chronic obstructive pulmonary disease
Rationale:
* A (Opioid overdose): Causes respiratory depression, leading to CO₂ retention.
* B (Pneumonia): Impairs gas exchange, leading to CO₂ buildup.
* D (COPD): Leads to chronic CO₂ retention.
C (Pulmonary embolism) typically causes respiratory alkalosis due to hyperventilation. E (NG suctioning) leads to metabolic alkalosis, not respiratory acidosis.
A patient has partially compensated metabolic alkalosis. Which ABG values would support this diagnosis?
A. pH 7.47, PaCO₂ 50 mmHg, HCO₃⁻ 32 mEq/L
B. pH 7.37, PaCO₂ 50 mmHg, HCO₃⁻ 30 mEq/L
C. pH 7.55, PaCO₂ 35 mmHg, HCO₃⁻ 30 mEq/L
D. pH 7.31, PaCO₂ 47 mmHg, HCO₃⁻ 20 mEq/L
A. pH 7.47, PaCO₂ 50 mmHg, HCO₃⁻ 32 mEq/L
Rationale:
* Metabolic alkalosis: High pH (>7.45) and high HCO₃⁻ (>26 mEq/L)
* Partial compensation: The PaCO₂ is elevated (>45 mmHg), indicating respiratory compensation.
Option B is fully compensated (normal pH).
A nurse is caring for a critically ill patient with severe sepsis. The patient has deep, rapid breathing (Kussmaul respirations) and an ABG indicating metabolic acidosis. The nurse anticipates which lab finding? (SATA)
A. Increased lactic acid levels
B. Elevated sodium levels
C. Decreased PaCO₂
D. Increased bicarbonate levels
A. Increased lactic acid levels
C. Decreased PaCO₂
Rationale:
* A (Increased lactic acid): Lactic acidosis occurs due to anaerobic metabolism in sepsis.
* C (Decreased PaCO₂): The lungs compensate by hyperventilating, reducing CO₂ to raise pH.
D (Increased bicarbonate) is incorrect—HCO₃⁻ is low in metabolic acidosis.
A 75-year-old patient with a history of chronic obstructive pulmonary disease (COPD) presents to the emergency department with increasing dyspnea, lethargy, and confusion. The patient is using accessory muscles to breathe. Arterial blood gas (ABG) results are:
* pH: 7.30
* PaCO₂: 58 mmHg
* HCO₃⁻: 26 mEq/L
Which of the following interventions is most appropriate at this time?
A. Encourage the patient to take deep, rapid breaths
B. Administer a high-flow oxygen mask at 100% FiO₂
C. Prepare for noninvasive positive pressure ventilation (BiPAP)
D. Administer sodium bicarbonate IV to correct the pH
C. Prepare for noninvasive positive pressure ventilation (BiPAP)
Rationale: The low pH and high PaCO₂ indicate acute respiratory acidosis due to hypoventilation. Noninvasive ventilation (e.g., BiPAP) helps improve gas exchange and prevent intubation. High-flow oxygen (B) can worsen CO₂ retention in COPD patients.
A patient with opioid overdose is found unresponsive with shallow respirations and pinpoint pupils. ABG results show:
* pH: 7.28
* PaCO₂: 55 mmHg
* HCO₃⁻: 24 mEq/L
Which medication should the nurse prepare to administer?
A. Flumazenil
B. Sodium bicarbonate
C. Naloxone
D. Albuterol
C. Naloxone
Rationale: High PaCO₂ and low pH indicate respiratory acidosis due to opioid-induced respiratory depression. Naloxone (Narcan) rapidly reverses opioid overdose by restoring respiratory drive.
A nurse is reviewing potential causes of respiratory acidosis. Which of the following conditions could lead to this imbalance? (SATA)
A. Guillain-Barré syndrome
B. Pulmonary embolism
C. Myasthenia gravis
D. Anxiety-induced hyperventilation
E. Pneumonia
A. Guillain-Barré syndrome
C. Myasthenia gravis
E. Pneumonia
Rationale:
* A (Guillain-Barré syndrome): Causes respiratory muscle weakness, leading to hypoventilation.
* C (Myasthenia gravis): Leads to impaired diaphragmatic function, reducing ventilation.
* E (Pneumonia): Can cause hypoventilation due to impaired gas exchange.
B (Pulmonary embolism) and D (Anxiety-induced hyperventilation) cause respiratory alkalosis, not acidosis.
A patient with acute respiratory acidosis is receiving mechanical ventilation. The pH remains low despite increasing ventilator support. The healthcare provider orders sodium bicarbonate IV. What is the nurse’s priority assessment before administration?
A. Serum sodium levels
B. Respiratory rate
C. Urine output
D. Serum bicarbonate levels
D. Serum bicarbonate levels
Rationale: Sodium bicarbonate is not typically given for respiratory acidosis unless severe acidosis (HCO₃⁻ <10 mEq/L) is present. If HCO₃⁻ is already elevated due to compensation, administering more can cause metabolic alkalosis.
A patient with chronic respiratory acidosis due to COPD has an ABG showing full compensation. Which values would be expected?
A. pH 7.36, PaCO₂ 52 mmHg, HCO₃⁻ 30 mEq/L
B. pH 7.31, PaCO₂ 50 mmHg, HCO₃⁻ 24 mEq/L
C. pH 7.50, PaCO₂ 30 mmHg, HCO₃⁻ 24 mEq/L
D. pH 7.44, PaCO₂ 40 mmHg, HCO₃⁻ 24 mEq/L
A. pH 7.36, PaCO₂ 52 mmHg, HCO₃⁻ 30 mEq/L
Rationale:
* Chronic respiratory acidosis shows compensation by the kidneys, increasing HCO₃⁻ to normalize pH.
* pH is within normal limits (but on the lower end), PaCO₂ is elevated, and HCO₃⁻ is increased to compensate.
A patient with severe respiratory acidosis is being mechanically ventilated. Which interventions can help correct this imbalance? (SATA)
A. Increase ventilator tidal volume
B. Increase ventilator respiratory rate
C. Administer IV sodium bicarbonate immediately
D. Encourage the patient to perform incentive spirometry
E. Decrease the patient’s oxygen flow rate
A. Increase ventilator tidal volume
B. Increase ventilator respiratory rate
Rationale:
* A (Increase tidal volume): Helps eliminate more CO₂.
* B (Increase respiratory rate): Promotes CO₂ exhalation, improving acidosis.
C (Administer sodium bicarbonate) is not first-line in respiratory acidosis. D (Incentive spirometry) is more effective for atelectasis, not CO₂ retention. E (Decreasing oxygen) could worsen hypoxemia.
A nurse is caring for a postoperative patient who received excessive sedation. The patient is difficult to arouse, with a respiratory rate of 8 breaths per minute and the following ABG results:
* pH: 7.29
* PaCO₂: 54 mmHg
* HCO₃⁻: 25 mEq/L
What is the priority nursing action?
A. Apply a non-rebreather mask at 15 L/min
B. Administer a sedative reversal agent
C. Place the patient in high Fowler’s position
D. Obtain a stat chest x-ray
B. Administer a sedative reversal agent
Rationale: The patient has respiratory acidosis due to hypoventilation from oversedation. Reversing sedation (e.g., with naloxone for opioids or flumazenil for benzodiazepines) restores respiratory drive and prevents further CO₂ buildup.
A 25-year-old patient comes to the emergency department with chest tightness, dizziness, and tingling in the fingers after an argument with their spouse. The patient’s respirations are 32 breaths per minute. ABG results are:
* pH: 7.50
* PaCO₂: 28 mmHg
* HCO₃⁻: 24 mEq/L
Which of the following interventions should the nurse implement first?
A. Administer lorazepam IV for anxiety
B. Prepare for endotracheal intubation
C. Apply oxygen via nasal cannula
D. Encourage slow, deep breathing into a paper bag
D. Encourage slow, deep breathing into a paper bag
Rationale: The patient’s symptoms and ABG indicate acute respiratory alkalosis due to hyperventilation from anxiety. Breathing into a paper bag helps rebreathe exhaled CO₂, restoring acid-base balance. Intubation is unnecessary unless severe distress occurs.
A patient with severe pneumonia develops tachypnea and an ABG showing respiratory alkalosis. What is the primary cause of this imbalance?
A. The lungs are retaining too much CO₂
B. The patient’s fever is increasing metabolic demand
C. The lungs are eliminating too much CO₂
D. The kidneys are excreting excess bicarbonate
C. The lungs are eliminating too much CO₂
Rationale: Respiratory alkalosis occurs when excess CO₂ is eliminated due to hyperventilation (e.g., tachypnea from pneumonia). This reduces carbonic acid, increasing pH.
A nurse is caring for a patient with respiratory alkalosis. Which of the following could be possible causes? (SATA)
A. Pulmonary embolism
B. Opioid overdose
C. Panic attack
D. Guillain-Barré syndrome
E. Fever
A. Pulmonary embolism
C. Panic attack
E. Fever
Rationale:
* A (Pulmonary embolism): Causes hypoxemia, leading to hyperventilation and CO₂ loss.
* C (Panic attack): Leads to hyperventilation, decreasing CO₂.
* E (Fever): Increases metabolic rate, stimulating the respiratory center to increase ventilation.
B (Opioid overdose) and D (Guillain-Barré syndrome) cause hypoventilation, leading to respiratory acidosis, not alkalosis.
A postoperative patient is experiencing severe pain and is breathing rapidly. ABG results show uncompensated respiratory alkalosis. What is the priority nursing action?
A. Encourage deep breathing exercises
B. Administer prescribed pain medication
C. Restrict fluid intake to prevent hyperventilation
D. Place the patient in the prone position
B. Administer prescribed pain medication
Rationale: Pain can cause hyperventilation, leading to CO₂ loss and respiratory alkalosis. Treating the underlying pain helps normalize respiration.
Which clinical manifestation would the nurse expect in a patient with acute respiratory alkalosis?
A. Confusion and lethargy
B. Bradypnea and cyanosis
C. Hyperkalemia and muscle weakness
D. Numbness and tingling in extremities
D. Numbness and tingling in extremities
Rationale: Decreased CO₂ causes a rise in pH, leading to neuromuscular irritability such as paresthesia (numbness/tingling), dizziness, and lightheadedness.
A nurse is educating a patient with chronic respiratory alkalosis due to pulmonary fibrosis. Which of the following statements indicate effective understanding? (SATA)
A. “My kidneys help compensate by excreting bicarbonate.”
B. “I need to monitor for signs of metabolic acidosis.”
C. “I should take deep, rapid breaths when I feel short of breath.”
D. “Hyperventilation can make my symptoms worse.”
E. “My body will naturally compensate by retaining CO₂ over time.”
A. “My kidneys help compensate by excreting bicarbonate.”
D. “Hyperventilation can make my symptoms worse.”
Rationale:
* A (Kidneys compensate by excreting bicarbonate): In chronic respiratory alkalosis, the kidneys lower HCO₃⁻ to balance pH.
* D (Hyperventilation worsens symptoms): Increased respirations worsen CO₂ loss, exacerbating alkalosis.
B (Monitor for metabolic acidosis) is incorrect because metabolic alkalosis is more likely. C (Take deep, rapid breaths) would worsen alkalosis. E (Retaining CO₂ naturally) is not a normal compensatory mechanism.
A patient with respiratory alkalosis is admitted with a PaCO₂ of 25 mmHg. Which electrolyte imbalance is most concerning?
A. Hyperkalemia
B. Hypocalcemia
C. Hypernatremia
D. Hyperchloremia
B. Hypocalcemia
Rationale: Alkalosis increases calcium binding to albumin, reducing ionized calcium levels, which can cause tetany, muscle spasms, and paresthesia.
A patient with asthma exacerbation is initially hyperventilating and develops respiratory alkalosis. After several hours, the patient becomes fatigued and drowsy. Repeat ABG shows:
* pH: 7.33
* PaCO₂: 50 mmHg
* HCO₃⁻: 24 mEq/L
Which of the following is the most concerning interpretation?
A. The patient is improving and compensating
B. The patient is at risk for respiratory failure
C. The patient has developed metabolic acidosis
D. The patient has fully compensated respiratory alkalosis
B. The patient is at risk for respiratory failure
Rationale: The ABG shows respiratory acidosis, indicating CO₂ retention due to fatigue. This suggests the patient is tiring out and may require ventilatory support.
Which interventions are appropriate for a patient with acute respiratory alkalosis? (SATA)
A. Have the patient breathe into a rebreather mask
B. Encourage slow, controlled breathing
C. Administer IV sodium bicarbonate
D. Treat the underlying cause
E. Increase the patient’s oxygen delivery
A. Have the patient breathe into a rebreather mask
B. Encourage slow, controlled breathing
D. Treat the underlying cause
Rationale:
* A (Rebreather mask): Helps retain CO₂.
* B (Slow breathing): Reduces hyperventilation, restoring normal CO₂ levels.
* D (Treat underlying cause): Addressing pain, anxiety, fever, or hypoxemia corrects alkalosis.
C (Sodium bicarbonate) is not given for respiratory alkalosis. E (Increasing oxygen) does not address CO₂ loss.
A 45-year-old patient with a history of chronic kidney disease presents with fatigue, nausea, and Kussmaul respirations. The nurse reviews the patient’s arterial blood gas (ABG) results:
* pH: 7.28
* PaCO₂: 35 mmHg
* HCO₃⁻: 18 mEq/L
* Anion gap: 15 mmol/L
Which of the following is the most likely cause of this patient’s metabolic acidosis?
A. Chronic diarrhea
B. Renal failure
C. Excessive vomiting
D. Diuretic overuse
B. Renal failure
Rationale: Metabolic acidosis with an increased anion gap can be caused by renal failure, which impairs the kidneys’ ability to excrete hydrogen ions and reabsorb bicarbonate. The normal PaCO₂ suggests that respiratory compensation is occurring but is not fully correcting the pH.
A nurse is caring for a patient with diabetic ketoacidosis (DKA). Which of the following clinical signs should the nurse expect?
A. Decreased respiratory rate
B. Hypertension
C. Hypokalemia
D. Kussmaul respirations
D. Kussmaul respirations
Rationale: DKA leads to metabolic acidosis, and the body compensates by increasing CO₂ excretion through deep, rapid Kussmaul respirations.
Which of the following are causes of high anion gap metabolic acidosis? (SATA)
A. Lactic acidosis
B. Renal failure
C. Diarrhea
D. Diabetic ketoacidosis
E. Salicylate toxicity
A. Lactic acidosis
B. Renal failure
D. Diabetic ketoacidosis
E. Salicylate toxicity
Rationale:
* A (Lactic acidosis): Increases lactate, raising the anion gap.
* B (Renal failure): Causes impaired acid excretion, leading to acid buildup.
* D (Diabetic ketoacidosis): Accumulation of ketone acids increases the anion gap.
* E (Salicylate toxicity): Leads to acid accumulation, contributing to metabolic acidosis.
C (Diarrhea) causes bicarbonate loss but does not increase the anion gap.
A patient with severe diarrhea presents to the emergency department with weakness, confusion, and tachycardia. ABG results indicate metabolic acidosis with a normal anion gap. What is the priority intervention?
A. Administer IV sodium bicarbonate
B. Encourage deep breathing
C. Replace fluids and electrolytes
D. Administer IV insulin
C. Replace fluids and electrolytes
Rationale: Diarrhea causes bicarbonate loss, leading to normal anion gap metabolic acidosis. Fluid and electrolyte replacement (especially bicarbonate and potassium) is the priority to restore acid-base balance.
Which electrolyte imbalance is most likely to occur in a patient with metabolic acidosis?
A. Hyperkalemia
B. Hypokalemia
C. Hypernatremia
D. Hypocalcemia
A. Hyperkalemia
Rationale: In metabolic acidosis, excess H+ moves into cells, forcing potassium (K⁺) out, leading to hyperkalemia.
A nurse is assessing a patient with shock-induced lactic acidosis. Which of the following clinical findings should be expected? (SATA)
A. Hypotension
B. Bradycardia
C. Increased serum lactate
D. Decreased urine output
E. Hyperventilation
A. Hypotension
C. Increased serum lactate
D. Decreased urine output
E. Hyperventilation
Rationale:
* A (Hypotension): Shock reduces tissue perfusion, leading to anaerobic metabolism and lactic acidosis.
* C (Increased serum lactate): Lactic acid accumulates due to hypoxia.
* D (Decreased urine output): Poor renal perfusion limits acid excretion.
* E (Hyperventilation): Compensation via increased CO₂ excretion.
B (Bradycardia) is incorrect; shock often causes tachycardia.
A patient with salicylate (aspirin) overdose is admitted with confusion and tachypnea. ABG results show:
* pH: 7.30
* PaCO₂: 25 mmHg
* HCO₃⁻: 14 mEq/L
* Anion gap: 18 mmol/L
Which of the following describes the acid-base imbalance?
A. Fully compensated metabolic acidosis
B. Uncompensated metabolic acidosis
C. Partially compensated metabolic acidosis
D. Mixed respiratory and metabolic acidosis
C. Partially compensated metabolic acidosis
Rationale: The low pH and HCO₃⁻ confirm metabolic acidosis. Low PaCO₂ indicates respiratory compensation, but since the pH is still abnormal, compensation is partial, not full.
A patient with metabolic acidosis due to diabetic ketoacidosis is receiving IV insulin and fluids. Which assessment finding indicates treatment is effective?
A. Decreased respiratory rate
B. Increased serum ketones
C. Worsening confusion
D. pH remains at 7.30
A. Decreased respiratory rate
Rationale: Insulin corrects ketoacidosis, reducing acid levels. As acidemia improves, Kussmaul respirations slow down.
A patient with a nasogastric (NG) tube for gastric decompression has had high-output suctioning for the past 48 hours. The patient is now weak and lethargic. ABG results show:
* pH: 7.49
* PaCO₂: 48 mmHg
* HCO₃⁻: 30 mEq/L
Which electrolyte imbalance is most commonly associated with this condition?
A. Hyperkalemia
B. Hypokalemia
C. Hypercalcemia
D. Hypernatremia
B. Hypokalemia
Rationale: Gastric suctioning causes loss of hydrochloric acid (HCl), leading to metabolic alkalosis. The kidneys compensate by excreting bicarbonate, but in the process, potassium is also lost, causing hypokalemia.
Which of the following clinical signs would the nurse expect in a patient with severe metabolic alkalosis?
A. Kussmaul respirations
B. Hypoventilation
C. Hyperreflexia
D. Increased anion gap
B. Hypoventilation
Rationale: In metabolic alkalosis, the respiratory system compensates by decreasing the respiratory rate to retain CO₂ and lower the pH. However, this compensation is limited by hypoxemia.
Which conditions are common causes of metabolic alkalosis? (SATA)
A. Prolonged vomiting
B. Diarrhea
C. Loop diuretic therapy
D. Excessive antacid use
E. Diabetic ketoacidosis
A. Prolonged vomiting
C. Loop diuretic therapy
D. Excessive antacid use
Rationale:
* A (Prolonged vomiting): Causes loss of gastric acid (HCl).
* C (Loop diuretics): Increase H+ and K+ loss, promoting alkalosis.
* D (Excessive antacid use): Increases bicarbonate, leading to alkalosis.
B (Diarrhea) leads to metabolic acidosis due to bicarbonate loss.
E (Diabetic ketoacidosis) causes metabolic acidosis due to ketone accumulation.
A patient with chronic heart failure is on long-term furosemide therapy. The patient reports fatigue, muscle cramps, and tingling in the fingers. Which intervention should the nurse anticipate?
A. Administer IV sodium bicarbonate
B. Stop the furosemide and administer IV fluids
C. Encourage deep breathing exercises
D. Administer potassium chloride
D. Administer potassium chloride
Rationale: Furosemide (a loop diuretic) causes metabolic alkalosis by increasing H+ and K+ loss. The symptoms of fatigue, muscle cramps, and tingling indicate hypokalemia, which needs correction with potassium replacement.
A patient with Cushing’s syndrome is admitted for weakness and confusion. ABG results show metabolic alkalosis. Which of the following is the most likely cause?
A. Increased mineralocorticoids
B. Excessive ketone production
C. Increased lactate production
D. Loss of bicarbonate
A. Increased mineralocorticoids
Rationale: Cushing’s syndrome causes excessive aldosterone (a mineralocorticoid) secretion, leading to H+ and K+ loss, promoting metabolic alkalosis.
A nurse is assessing a patient with metabolic alkalosis. Which neuromuscular symptoms would the nurse expect? (SATA)
A. Tetany
B. Positive Chvostek’s sign
C. Muscle twitching
D. Bradycardia
E. Confusion
A. Tetany
B. Positive Chvostek’s sign
C. Muscle twitching
E. Confusion
Rationale:
* A (Tetany): Due to low ionized calcium in alkalosis.
* B (Positive Chvostek’s sign): Indicates hypocalcemia, which can occur in alkalosis.
* C (Muscle twitching): Related to electrolyte disturbances.
* E (Confusion): Results from altered neuronal function.
D (Bradycardia) is incorrect; tachycardia is more common in fluid loss-related alkalosis.
A patient with metabolic alkalosis is hypovolemic and hypotensive. Which IV fluid would be most appropriate for this patient?
A. 0.45% normal saline
B. 3% hypertonic saline
C. 0.9% normal saline
D. D5W
C. 0.9% normal saline
Rationale: Metabolic alkalosis with volume depletion is best treated with isotonic saline (0.9% NS) to restore volume and correct chloride loss.
A patient with COPD and chronic respiratory acidosis is vomiting excessively due to a gastrointestinal infection. ABG results show:
* pH: 7.38
* PaCO₂: 55 mmHg
* HCO₃⁻: 34 mEq/L
How should the nurse interpret these findings?
A. Mixed respiratory and metabolic acidosis
B. Mixed respiratory acidosis and metabolic alkalosis
C. Acute respiratory acidosis
D. Uncompensated metabolic alkalosis
B. Mixed respiratory acidosis and metabolic alkalosis
Rationale: The patient has chronic respiratory acidosis (PaCO₂ > 45 mmHg) due to COPD. Vomiting leads to metabolic alkalosis (HCO₃⁻ > 26 mEq/L). The pH appears near-normal, but this is due to the mixed disorder balancing each other out.
A patient with severe septic shock is found to have the following ABG results:
* pH: 7.10
* PaCO₂: 50 mmHg
* HCO₃⁻: 16 mEq/L
Which mixed acid-base disorder is most likely present?
A. Mixed metabolic acidosis and respiratory acidosis
B. Mixed metabolic alkalosis and respiratory acidosis
C. Metabolic acidosis with full respiratory compensation
D. Uncompensated metabolic acidosis
A. Mixed metabolic acidosis and respiratory acidosis
Rationale:
* The low pH (7.10) confirms acidosis.
* The high PaCO₂ (50 mmHg) suggests respiratory acidosis.
* The low HCO₃⁻ (16 mEq/L) suggests metabolic acidosis.
* The presence of both metabolic and respiratory acidosis indicates severe shock with poor perfusion and hypoventilation.
Which conditions can cause a mixed acid-base disorder? (SATA)
A. Severe sepsis with respiratory failure
B. Diabetic ketoacidosis with vomiting
C. Pneumonia with prolonged NG suction
D. Anxiety-induced hyperventilation with diarrhea
E. Opioid overdose with dehydration
A. Severe sepsis with respiratory failure
B. Diabetic ketoacidosis with vomiting
C. Pneumonia with prolonged NG suction
E. Opioid overdose with dehydration
Rationale:
* A (Sepsis with respiratory failure): Causes metabolic acidosis (lactic acidosis) and respiratory acidosis (hypoventilation).
* B (DKA with vomiting): Causes metabolic acidosis (ketones) and metabolic alkalosis (vomiting H+ loss).
* C (Pneumonia with NG suction): Causes respiratory acidosis (hypoventilation) and metabolic alkalosis (loss of gastric acid).
* E (Opioid overdose with dehydration): Causes respiratory acidosis (hypoventilation) and metabolic acidosis (hypoperfusion, lactic acid accumulation).
D (Anxiety hyperventilation with diarrhea) is incorrect because it combines respiratory alkalosis (hyperventilation) and metabolic acidosis (diarrhea loss of HCO₃⁻), which is not a mixed disorder but rather a compensation mechanism.
A postoperative patient receiving opioids for pain control has an NG tube for gastric decompression. The nurse notes that the patient is hypoventilating and is becoming lethargic. Which acid-base imbalance is the patient most likely experiencing?
A. Uncompensated respiratory acidosis
B. Fully compensated metabolic alkalosis
C. Mixed respiratory acidosis and metabolic alkalosis
D. Mixed metabolic acidosis and respiratory alkalosis
C. Mixed respiratory acidosis and metabolic alkalosis
Rationale:
* Opioids cause respiratory depression, leading to respiratory acidosis.
* NG suctioning removes H+ from the stomach, causing metabolic alkalosis.
* Since these disorders are opposite, the pH may appear near-normal, but this represents a mixed disorder.
A patient with pneumonia has been hyperventilating due to hypoxia and also has been vomiting. Which ABG result would most likely indicate a mixed acid-base disorder?
A. pH 7.47, PaCO₂ 32 mmHg, HCO₃⁻ 28 mEq/L
B. pH 7.32, PaCO₂ 48 mmHg, HCO₃⁻ 24 mEq/L
C. pH 7.28, PaCO₂ 55 mmHg, HCO₃⁻ 30 mEq/L
D. pH 7.40, PaCO₂ 38 mmHg, HCO₃⁻ 24 mEq/L
A. pH 7.47, PaCO₂ 32 mmHg, HCO₃⁻ 28 mEq/L
Rationale:
* The high pH indicates alkalosis.
* The low PaCO₂ (32 mmHg) suggests respiratory alkalosis (hyperventilation).
* The high HCO₃⁻ (28 mEq/L) suggests metabolic alkalosis (vomiting).
* This confirms mixed alkalosis.
A patient with mixed metabolic acidosis and respiratory acidosis may present with which symptoms? (SATA)
A. Confusion
B. Kussmaul respirations
C. Hypotension
D. Hyperreflexia
E. Hypoventilation
A. Confusion
B. Kussmaul respirations
C. Hypotension
E. Hypoventilation
Rationale:
* A (Confusion): Due to altered cerebral perfusion.
* B (Kussmaul respirations): Due to metabolic acidosis compensation.
* C (Hypotension): Due to severe acidosis and shock.
* E (Hypoventilation): Due to respiratory acidosis from CO₂ retention.
D (Hyperreflexia) is incorrect—acidosis typically causes depressed reflexes rather than hyperreflexia.
A patient with a history of severe anxiety and hyperventilation is now experiencing severe diarrhea. Which acid-base imbalance should the nurse expect?
A. Compensated respiratory alkalosis
B. Mixed metabolic acidosis and respiratory alkalosis
C. Mixed metabolic alkalosis and respiratory acidosis
D. Fully compensated metabolic acidosis
B. Mixed metabolic acidosis and respiratory alkalosis
Rationale:
* Hyperventilation (anxiety) causes respiratory alkalosis.
* Severe diarrhea causes metabolic acidosis (loss of HCO₃⁻).
* Since these are opposite imbalances, this results in a mixed disorder.
A patient in acute renal failure with pneumonia is drowsy and dyspneic. ABG results show:
* pH: 7.25
* PaCO₂: 50 mmHg
* HCO₃⁻: 18 mEq/L
Which intervention should the nurse anticipate?
A. Prepare for mechanical ventilation
B. Administer sodium bicarbonate
C. Encourage deep breathing exercises
D. Give an anti-anxiety medication
A. Prepare for mechanical ventilation
Rationale:
* The patient has mixed respiratory acidosis (PaCO₂ > 45 mmHg) and metabolic acidosis (HCO₃⁻ < 22 mEq/L).
* The low pH (7.25) suggests severe acidemia.
* Mechanical ventilation is needed to improve CO₂ elimination and oxygenation.
A patient with uncontrolled diabetes mellitus arrives at the emergency department with rapid, deep respirations, confusion, and weakness. Arterial blood gases reveal:
* pH: 7.21
* PaCO₂: 30 mmHg
* HCO₃⁻: 14 mEq/L
Which clinical finding should the nurse anticipate?
A. Tetany and muscle twitching
B. Bradycardia and hypotension
C. Kussmaul respirations and drowsiness
D. Hyperreflexia and tremors
C. Kussmaul respirations and drowsiness
Rationale:
* Metabolic acidosis is confirmed by low pH (7.21) and low HCO₃⁻ (14 mEq/L).
* Kussmaul respirations (deep, rapid breathing) occur as the lungs attempt to compensate by exhaling CO₂.
* The CNS is depressed, leading to confusion, weakness, and drowsiness.
A patient with COPD is admitted with lethargy, confusion, and a headache. The patient’s respirations are shallow and slow. Which acid-base imbalance should the nurse suspect?
A. Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Respiratory alkalosis
B. Respiratory acidosis
Rationale:
* COPD causes CO₂ retention, leading to respiratory acidosis.
* Lethargy, confusion, and headache result from CNS depression caused by elevated CO₂ levels.
* Hypoventilation (shallow, slow breathing) worsens CO₂ retention.
Which clinical manifestations should the nurse expect in a patient with respiratory alkalosis? (SATA)
A. Lightheadedness
B. Numbness and tingling in fingers
C. Muscle cramping
D. Decreased deep tendon reflexes
E. Tetany
A. Lightheadedness
B. Numbness and tingling in fingers
C. Muscle cramping
E. Tetany
Rationale:
* Respiratory alkalosis leads to hypocalcemia due to increased calcium binding to albumin.
* This causes neuromuscular excitability, leading to:
* A (Lightheadedness) from cerebral vasoconstriction
* B (Numbness/tingling in fingers) & C (Muscle cramping) from hypocalcemia
* E (Tetany) due to increased nerve excitability
D (Decreased deep tendon reflexes) is incorrect—alkalosis increases excitability, leading to hyperreflexia, not depressed reflexes.
A postoperative patient with an NG tube for gastric decompression is restless, complaining of tingling in the fingers and muscle cramps. The patient’s respirations are shallow and slow. Which intervention should the nurse anticipate?
A. Encourage the patient to take deep breaths
B. Administer IV sodium bicarbonate
C. Discontinue the NG tube suction
D. Administer a calcium supplement
C. Discontinue the NG tube suction
Rationale:
* Prolonged NG suctioning leads to loss of gastric acid, causing metabolic alkalosis.
* Tingling fingers, muscle cramps, and shallow respirations indicate hypocalcemia and CNS excitability from alkalosis.
* Stopping NG suctioning prevents further H+ loss, helping correct the imbalance.
A patient with severe diarrhea reports fatigue, dizziness, and weakness. The nurse notes hypotension and Kussmaul respirations. Which electrolyte imbalance is most likely present?
A. Hypercalcemia
B. Hypocalcemia
C. Hyperkalemia
D. Hypokalemia
D. Hypokalemia
Rationale:
* Severe diarrhea leads to loss of bicarbonate, causing metabolic acidosis.
* It also leads to potassium loss, resulting in hypokalemia.
* Hypokalemia causes:
* Weakness, fatigue, dizziness (decreased muscle function)
* Hypotension (due to fluid shifts)
* Kussmaul respirations (compensation for acidosis)
A patient with metabolic acidosis may exhibit which clinical manifestations? (SATA)
A. Confusion and drowsiness
B. Warm, flushed skin
C. Shallow, slow breathing
D. Weakness and lethargy
E. Nausea and vomiting
A. Confusion and drowsiness
B. Warm, flushed skin
D. Weakness and lethargy
E. Nausea and vomiting
Rationale:
* A (Confusion and drowsiness): CNS depression from acidosis.
* B (Warm, flushed skin): Due to vasodilation from acidosis.
* D (Weakness and lethargy): Caused by depressed neuromuscular activity.
* E (Nausea and vomiting): The body tries to eliminate acid via the GI tract.
C (Shallow, slow breathing) is incorrect—metabolic acidosis triggers Kussmaul respirations (deep, rapid breathing) to compensate.
A patient with a panic attack presents to the ER with hyperventilation, palpitations, dizziness, and perioral tingling. The nurse expects which ABG values?
A. pH 7.48, PaCO₂ 30 mmHg, HCO₃⁻ 23 mEq/L
B. pH 7.28, PaCO₂ 50 mmHg, HCO₃⁻ 24 mEq/L
C. pH 7.35, PaCO₂ 40 mmHg, HCO₃⁻ 22 mEq/L
D. pH 7.21, PaCO₂ 30 mmHg, HCO₃⁻ 15 mEq/L
A. pH 7.48, PaCO₂ 30 mmHg, HCO₃⁻ 23 mEq/L
Rationale:
* Hyperventilation leads to excessive CO₂ loss, causing respiratory alkalosis.
* Elevated pH (7.48) confirms alkalosis.
* PaCO₂ < 35 mmHg (30 mmHg) indicates CO₂ loss from hyperventilation.
* Normal HCO₃⁻ (23 mEq/L) shows no metabolic compensation yet.
A patient with metabolic alkalosis develops seizures and muscle twitching. What is the most likely cause of these symptoms?
A. Hyperkalemia
B. Hypocalcemia
C. Hyperphosphatemia
D. Hyponatremia
B. Hypocalcemia
Rationale:
* Metabolic alkalosis increases calcium binding to albumin, reducing ionized (active) calcium levels.
* Low ionized calcium leads to:
* Neuromuscular excitability (muscle twitching, tetany, seizures).
* Perioral tingling, numbness, and carpopedal spasms.
A patient with uncontrolled diabetes mellitus arrives at the emergency department with rapid, deep respirations, confusion, and weakness. Arterial blood gases reveal:
* pH: 7.21
* PaCO₂: 30 mmHg
* HCO₃⁻: 14 mEq/L
Which clinical finding should the nurse anticipate?
A. Tetany and muscle twitching
B. Bradycardia and hypotension
C. Kussmaul respirations and drowsiness
D. Hyperreflexia and tremors
C. Kussmaul respirations and drowsiness
Rationale:
* Metabolic acidosis is confirmed by low pH (7.21) and low HCO₃⁻ (14 mEq/L).
* Kussmaul respirations (deep, rapid breathing) occur as the lungs attempt to compensate by exhaling CO₂.
* The CNS is depressed, leading to confusion, weakness, and drowsiness.
A patient with COPD is admitted with lethargy, confusion, and a headache. The patient’s respirations are shallow and slow. Which acid-base imbalance should the nurse suspect?
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory alkalosis
D. Respiratory acidosis
D. Respiratory acidosis
Rationale:
* COPD causes CO₂ retention, leading to respiratory acidosis.
* Lethargy, confusion, and headache result from CNS depression caused by elevated CO₂ levels.
* Hypoventilation (shallow, slow breathing) worsens CO₂ retention.
Which clinical manifestations should the nurse expect in a patient with respiratory alkalosis? (SATA)
A. Lightheadedness
B. Numbness and tingling in fingers
C. Muscle cramping
D. Decreased deep tendon reflexes
E. Tetany
A. Lightheadedness
B. Numbness and tingling in fingers
C. Muscle cramping
E. Tetany
Rationale:
* Respiratory alkalosis leads to hypocalcemia due to increased calcium binding to albumin.
* This causes neuromuscular excitability, leading to:
* A (Lightheadedness) from cerebral vasoconstriction
* B (Numbness/tingling in fingers) & C (Muscle cramping) from hypocalcemia
* E (Tetany) due to increased nerve excitability
D (Decreased deep tendon reflexes) is incorrect—alkalosis increases excitability, leading to hyperreflexia, not depressed reflexes.
A patient with severe diarrhea reports fatigue, dizziness, and weakness. The nurse notes hypotension and Kussmaul respirations. Which electrolyte imbalance is most likely present?
A. Hypercalcemia
B. Hypocalcemia
C. Hyperkalemia
D. Hypokalemia
D. Hypokalemia
Rationale:
* Severe diarrhea leads to loss of bicarbonate, causing metabolic acidosis.
* It also leads to potassium loss, resulting in hypokalemia.
* Hypokalemia causes:
* Weakness, fatigue, dizziness (decreased muscle function)
* Hypotension (due to fluid shifts)
* Kussmaul respirations (compensation for acidosis)
A patient with metabolic acidosis may exhibit which clinical manifestations? (SATA)
A. Confusion and drowsiness
B. Warm, flushed skin
C. Shallow, slow breathing
D. Weakness and lethargy
E. Nausea and vomiting
A. Confusion and drowsiness
B. Warm, flushed skin
D. Weakness and lethargy
E. Nausea and vomiting
Rationale:
* A (Confusion and drowsiness): CNS depression from acidosis.
* B (Warm, flushed skin): Due to vasodilation from acidosis.
* D (Weakness and lethargy): Caused by depressed neuromuscular activity.
* E (Nausea and vomiting): The body tries to eliminate acid via the GI tract.
C (Shallow, slow breathing) is incorrect—metabolic acidosis triggers Kussmaul respirations (deep, rapid breathing) to compensate.
A patient with a panic attack presents to the ER with hyperventilation, palpitations, dizziness, and perioral tingling. The nurse expects which ABG values?
A. pH 7.48, PaCO₂ 30 mmHg, HCO₃⁻ 23 mEq/L
B. pH 7.28, PaCO₂ 50 mmHg, HCO₃⁻ 24 mEq/L
C. pH 7.35, PaCO₂ 40 mmHg, HCO₃⁻ 22 mEq/L
D. pH 7.21, PaCO₂ 30 mmHg, HCO₃⁻ 15 mEq/L
A. pH 7.48, PaCO₂ 30 mmHg, HCO₃⁻ 23 mEq/L
Rationale:
* Hyperventilation leads to excessive CO₂ loss, causing respiratory alkalosis.
* Elevated pH (7.48) confirms alkalosis.
* PaCO₂ < 35 mmHg (30 mmHg) indicates CO₂ loss from hyperventilation.
* Normal HCO₃⁻ (23 mEq/L) shows no metabolic compensation yet.
A patient with metabolic alkalosis develops seizures and muscle twitching. What is the most likely cause of these symptoms?
A. Hyperkalemia
B. Hypocalcemia
C. Hyperphosphatemia
D. Hyponatremia
B. Hypocalcemia
Rationale:
* Metabolic alkalosis increases calcium binding to albumin, reducing ionized (active) calcium levels.
* Low ionized calcium leads to:
* Neuromuscular excitability (muscle twitching, tetany, seizures).
* Perioral tingling, numbness, and carpopedal spasms.
A postoperative patient with NG suction reports dizziness, tingling in the fingers, and muscle cramps. The nurse notes hyperreflexia and tachycardia. Which acid-base imbalance should the nurse suspect?
A. Respiratory acidosis
B. Metabolic alkalosis
C. Respiratory alkalosis
D. Metabolic acidosis
B. Metabolic alkalosis
Rationale:
* NG suctioning removes gastric acid (HCl), causing a bicarbonate excess → metabolic alkalosis.
* Symptoms include neuromuscular excitability (tingling, muscle cramps, hyperreflexia) and cardiovascular effects (tachycardia, dysrhythmias).
A patient experiencing a panic attack presents with light-headedness, dizziness, tachycardia, and tingling in the fingers. What is the priority nursing intervention?
A. Administer IV bicarbonate
B. Instruct the patient to breathe into a paper bag
C. Place the patient in a high-Fowler’s position
D. Administer an anti-anxiety medication
B. Instruct the patient to breathe into a paper bag
Rationale:
* Hyperventilation from a panic attack leads to respiratory alkalosis (excessive CO₂ loss).
* Rebreathing CO₂ (paper bag method) helps restore acid-base balance.
Which neuromuscular manifestations should the nurse expect in a patient with alkalosis? (SATA)
A. Tetany
B. Numbness
C. Hyperreflexia
D. Muscle weakness
E. Tremors
A. Tetany
B. Numbness
C. Hyperreflexia
E. Tremors
Rationale:
* Alkalosis causes neuromuscular excitability, leading to:
* A (Tetany) – involuntary muscle contractions
* B (Numbness) & E (Tremors) – due to hypocalcemia
* C (Hyperreflexia) – increased deep tendon reflexes
* D (Muscle weakness) is incorrect—weakness is more common in acidosis.
A patient with vomiting for 2 days has hypotension, tachycardia, tremors, and tingling in the toes. The nurse anticipates which ABG results?
A. pH 7.50, PaCO₂ 40 mmHg, HCO₃⁻ 30 mEq/L
B. pH 7.30, PaCO₂ 52 mmHg, HCO₃⁻ 24 mEq/L
C. pH 7.20, PaCO₂ 28 mmHg, HCO₃⁻ 14 mEq/L
D. pH 7.35, PaCO₂ 45 mmHg, HCO₃⁻ 22 mEq/L
A. pH 7.50, PaCO₂ 40 mmHg, HCO₃⁻ 30 mEq/L
Rationale:
* Vomiting leads to loss of stomach acid, causing metabolic alkalosis (pH > 7.45, ↑ HCO₃⁻).
* Tingling, tremors, and tachycardia are classic signs of alkalosis.
Which cardiovascular finding is expected in both metabolic and respiratory alkalosis?
A. Bradycardia
B. Tachycardia
C. Hypotension
D. Ventricular fibrillation
B. Tachycardia
Rationale:
* Alkalosis increases heart rate due to compensatory sympathetic stimulation.
* Tachycardia and dysrhythmias occur due to hypokalemia.
A patient with alkalosis may experience which gastrointestinal manifestations? (SATA)
A. Nausea
B. Vomiting
C. Diarrhea
D. Epigastric pain
E. Anorexia
A. Nausea
B. Vomiting
D. Epigastric pain
E. Anorexia
Rationale:
* Gastrointestinal effects of alkalosis include:
* A (Nausea) & B (Vomiting) – due to acid-base imbalance
* D (Epigastric pain) & E (Anorexia) – from gastric irritation
* C (Diarrhea) is incorrect—diarrhea is more common in acidosis.
A patient with mechanical ventilation is set at a high respiratory rate and develops confusion, light-headedness, and tachycardia. Which acid-base imbalance is most likely present?
A. Respiratory alkalosis
B. Respiratory acidosis
C. Metabolic acidosis
D. Metabolic alkalosis
A. Respiratory alkalosis
Rationale:
* High ventilation rates cause excessive CO₂ loss, leading to respiratory alkalosis.
* Confusion, light-headedness, and tachycardia are common symptoms.
A patient with metabolic alkalosis may develop which respiratory pattern as a compensatory response?
A. Kussmaul respirations
B. Apnea
C. Cheyne-Stokes respirations
D. Hypoventilation
D. Hypoventilation
Rationale: The lungs compensate for metabolic alkalosis by decreasing respiratory rate (hypoventilation) to retain CO₂ and lower pH.
Which electrolyte imbalances are commonly associated with alkalosis? (SATA)
A. Hypokalemia
B. Hyperkalemia
C. Hypocalcemia
D. Hypercalcemia
E. Hyponatremia
A. Hypokalemia
C. Hypocalcemia
Rationale:
* Alkalosis causes hypokalemia (A) due to intracellular K+ shifting.
* Alkalosis increases calcium binding to albumin, leading to hypocalcemia (C).
A patient taking diuretics presents with irritability, tremors, tachycardia, and anorexia. The nurse should suspect which acid-base disorder?
A. Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Respiratory alkalosis
C. Metabolic alkalosis
Rationale:
* Diuretics (loop and thiazide) cause loss of H+ and K+, leading to metabolic alkalosis.
* Symptoms include neuromuscular excitability (tremors, irritability), tachycardia, and anorexia.
Which intervention is priority for a patient with respiratory alkalosis due to hyperventilation?
A. Administer IV bicarbonate
B. Encourage slow, controlled breathing
C. Give oxygen at 2 L/min
D. Monitor for bradycardia
B. Encourage slow, controlled breathing
Rationale: Slowing the respiratory rate prevents excessive CO₂ loss and corrects alkalosis.
Which clinical manifestations should the nurse expect in a patient with respiratory alkalosis? (SATA)
A. Light-headedness
B. Tetany
C. Cyanosis
D. Tingling of extremities
E. Seizures
A. Light-headedness
B. Tetany
D. Tingling of extremities
E. Seizures
Rationale:
* Respiratory alkalosis symptoms include:
* A (Light-headedness) – due to cerebral vasoconstriction
* B (Tetany) & D (Tingling) – due to hypocalcemia
* E (Seizures) – severe neuromuscular excitability
* C (Cyanosis) is incorrect—cyanosis is seen in respiratory acidosis.
A 65-year-old patient with COPD is admitted with dyspnea and confusion. The nurse reviews the ABG results:
* pH: 7.30
* PaCO₂: 55 mmHg
* HCO₃⁻: 26 mEq/L
* PaO₂: 68 mmHg
Which acid-base imbalance is present?
A. Respiratory acidosis, uncompensated
B. Metabolic acidosis, partially compensated
C. Respiratory acidosis, partially compensated
D. Metabolic alkalosis, fully compensated
A. Respiratory acidosis, uncompensated
Rationale:
* Low pH (7.30) = Acidosis
* Elevated PaCO₂ (55 mmHg) = Respiratory cause
* Normal HCO₃⁻ (26 mEq/L) = No metabolic compensation
* Conclusion: Uncompensated respiratory acidosis
A patient has an ABG showing pH 7.47, PaCO₂ 30 mmHg, and HCO₃⁻ 24 mEq/L. What is the most likely cause of this imbalance?
A. Vomiting
B. Opioid overdose
C. Panic attack
D. Diabetic ketoacidosis
C. Panic attack
Rationale:
* High pH (7.47) = Alkalosis
* Low PaCO₂ (30 mmHg) = Respiratory cause
* Normal HCO₃⁻ (24 mEq/L) = No metabolic compensation
* Conclusion: Respiratory alkalosis from hyperventilation due to a panic attack
Which ABG components provide information about oxygenation status? (SATA)
A. pH
B. PaO₂
C. PaCO₂
D. HCO₃⁻
E. O₂ saturation
B. PaO₂
E. O₂ saturation
Rationale:
* B (PaO₂) measures arterial oxygen levels.
* E (O₂ saturation) shows the percentage of hemoglobin bound to oxygen.
* A (pH), C (PaCO₂), and D (HCO₃⁻) relate to acid-base balance, not oxygenation.
A patient with kidney failure has the following ABG results:
* pH: 7.28
* PaCO₂: 38 mmHg
* HCO₃⁻: 16 mEq/L
What compensatory mechanism should the nurse expect?
A. Kidneys excreting bicarbonate
B. Lungs increasing respiratory rate
C. Kidneys retaining hydrogen ions
D. Lungs decreasing respiratory rate
B. Lungs increasing respiratory rate
Rationale:
* Low pH (7.28) = Acidosis
* Low HCO₃⁻ (16 mEq/L) = Metabolic cause
* Normal PaCO₂ (38 mmHg) = No compensation yet
* To compensate, the lungs increase respiratory rate (Kussmaul respirations) to “blow off” CO₂ and raise pH.
The lungs act as an acid-base buffer by:
a. increasing respiratory rate and depth when CO2 levels in the blood are high, reducing acid load.
b. increasing respiratory rate and depth when CO2 levels in the blood are low, reducing base load.
c. decreasing respiratory rate and depth when CO2 levels in the blood are high, reducing acid load.
d. decreasing respiratory rate and depth when CO2 levels in the blood are low, increasing acid load.
a. increasing respiratory rate and depth when CO2 levels in the blood are high, reducing acid load.
A patient has the following arterial blood gas results: pH 7.52, PaCO2 30 mm Hg, 24 mEq/L. The nurse determines that these results indicate
a. metabolic acidosis.
b. metabolic alkalosis.
c. respiratory acidosis.
d. respiratory alkalosis.
d. respiratory alkalosis.
A patient who was involved in a motor vehicle crash has had a tracheostomy placed to allow for continued mechanical ventilation. How would the nurse interpret the following arterial blood gas results: pH 7.48, PaO 2 85 mm Hg, PaCO 2 32 mm Hg, and HCO 3 25 mEq/L?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis
d. Respiratory alkalosis
Rationale: The pH indicates that the patient has alkalosis and the low PaCO2 indicates a respiratory cause. The other responses are incorrect based on the pH and the normal HCO3.
A patient who was admitted with diabetic ketoacidosis has rapid, deep respirations. Which action would the nurse take?
a. Give the prescribed PRN lorazepam (Ativan).
b. Encourage the patient to take deep slow breaths.
c. Start the prescribed PRN oxygen at 2 to 4 L/min.
d. Administer the prescribed fluid bolus and insulin.
d. Administer the prescribed fluid bolus and insulin.
ANS: D
The rapid, deep (Kussmaul) respirations indicate a metabolic acidosis and the need for correction of the acidosis with a saline bolus to prevent hypovolemia followed by insulin administration to allow glucose to reenter the cells. Oxygen therapy is not indicated because there is no indication that the increased respiratory rate is related to hypoxemia. The respiratory pattern is compensatory, and the patient will not be able to slow the respiratory rate. Lorazepam administration will slow the respiratory rate and increase the level of acidosis.
A patient who is lethargic with deep, rapid respirations has the following arterial blood gas (ABG) results: pH 7.32, PaO2 88 mm Hg, PaCO2 35 mm Hg, and HCO3 16 mEq/L. How would the nurse interpret these results?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis
a. Metabolic acidosis
Rationale: The pH and HCO3 indicate that the patient has a metabolic acidosis. the ABGs are inconsistent with the other responses.
The laboratory technician calls with arterial blood gas (ABG) results on four patients. Which result is most important for the nurse to report immediately to the health care provider?
a. pH 7.34, PaO2 82 mm Hg, PaCO2 40 mm Hg, and O 2 sat 97%
b. pH 7.35, PaO2 85 mm Hg, PaCO2 50 mm Hg, and O 2 sat 95%
c. pH 7.46, PaO2 90 mm Hg, PaCO2 32 mm Hg, and O2 sat 98%
d. pH 7.31, PaO2 91 mm Hg, PaCO2 50 mm Hg, and O 2 sat 96%
d. pH 7.31, PaO2 91 mm Hg, PaCO2 50 mm Hg, and O2 sat 96%
Rationale: ABGs with a decreased pH and increased PaCO2 indicate uncompensated respiratory acidosis and should be reported to the health care provider. the other values are normal, close to normal, or compensated.
acidosis, normal, or alkalosis
pH < 7.35
acidosis
acidosis, normal, or alkalosis
pH > 7.45
alkalosis
acidosis, normal, or alkalosis
CO2 > 45
acidosis
acidosis, normal, or alkalosis
CO2 < 35
alkalosis
acidosis, normal, or alkalosis
HCO3 < 22
acidosis
acidosis, normal, or alkalosis
HCO3 > 26
alkalosis
If the pH is out of range & CO2
or HCO3 is in range:
a. uncompensated
b. partially compensated
c. fully compensated
a. uncompensated
If CO2 and HCO3 are BOTH out of range & the PH is out of range
a. uncompensated
b. partially compensated
c. fully compensated
b. partially compensated
If PH is in range (7.35 - 7.45):
a. uncompensated
b. partially compensated
c. fully compensated
c. fully compensated
