Acid-Base Balance

Which Acid-Base Disorder?

100

The nurse is caring for a client with a nasogastric tube that is attached to low suction. The nurse monitors the client, knowing that the client is at risk for which acid-base disorder? 1. Metabolic acidosis 2. Metabolic alkalosis 3. Respiratory acidosis 4. Respiratory alkalosis

Metabolic alkalosis is defined as a deficit or loss of hydrogen ions or acids or an excess of base (bicarbonate) that results from the accumulation of base or from a loss of acid without a comparable loss of base in the body fluids. Loss of gastric fluid via nasogastric suction or vomiting causes metabolic alkalosis as a result of the loss of hydrochloric acid. The remaining options are incorrect interpretations.

200

The nurse caring for a client with an ileostomy understands that the client is most at risk for developing which acid-base disorder? 1. Metabolic acidosis 2. Metabolic alkalosis 3. Respiratory acidosis 4. Respiratory alkalosis

Metabolic acidosis is defined as a total concentration of buffer base that is lower than normal, with a relative increase in the hydrogen ion concentration. Intestinal secretions are high in bicarbonate and may be lost through enteric drainage tubes, an ileostomy, or diarrhea.

300

A client who is found unresponsive has arterial blood gases drawn and the results indicate the following: pH is 7.12, Pco 2 is 90 mm Hg, and is HCO3- 22 mEq/L. The nurse interprets the results as indicating which condition? 1. Metabolic acidosis with compensation 2. Respiratory acidosis with compensation 3. Metabolic acidosis without compensation 4. Respiratory acidosis without compensation

4. Respiratory acidosis without compensation The acid-base disturbance is respiratory acidosis without compensation. The normal pH is 7.35 to 7.45. The normal Pco 2 is 35 to 45 mm Hg. In respiratory acidosis the pH is decreased and the Pco 2 is elevated. The normal bicarbonate (HCO3-) level is 22 to 27 mEq/L. Because the bicarbonate is still within normal limits, the kidneys have not had time to adjust for this acid-base disturbance.

400

The nurse plans care for a client with chronic obstructive pulmonary disease (COPD), understanding that the client is most likely to experience what type of acid-base imbalance? 1. Metabolic acidosis 2. Metabolic alkalosis 3. Respiratory acidosis 4. Respiratory alkalosis

3. Respiratory acidosis Respiratory acidosis is most often caused by hypoventilation in a client with COPD. Other acid-base disturbances can occur in a client with COPD during exacerbation of the disease, but the most likely imbalance is respiratory acidosis. COPD is a respiratory condition, not a metabolic one. Respiratory alkalosis is associated with hyperventilation.

500

Which Acid-Base Disorder is often the result of shock and uncontrolled diabetes?

Metabolic Acidosis

Fundamental Concepts

100

Why does potassium rise during acidosis?

The body protects itself from the acidic state by moving hydrogen ions into the cells. Therefore potassium moves out to make room for hydrogen ions and the potassium level increases.

200

Why does potassium drop during alkalosis?

The cells release hydrogen ions into the blood in an attempt to increase the acidity of the blood; this forces the potassium into the cells and potassium levels decrease.

300

What is the normal serum potassium level?

3.5-5.0 mEq/L

400

Describe 3 mechanisms used to maintain pH?

Kidneys Lungs Buffers

500

Which acid-base balance systems is the fastest.

Buffers

Metabolic Alkalosis/ Metabolic Acidosis

100

A client with a 3-day history of nausea and vomiting. The client is hypoventilating & has a respiratory rate of 10 breaths/minute. ABG's are? 

1.Decreased pH and an increased CO 2 

2. Increased pH and a decreased CO 2 

3. Decreased pH and a decreased HCO3-   

4. Increased pH with an increased HCO3-

4. An increased pH with an increased HCO3-

RATIONALE: Clients experiencing nausea and vomiting would most likely present with metabolic alkalosis resulting from loss of gastric acid, thus causing the pH and HCO3- to increase. Symptoms experienced by the client would include hypoventilation and tachycardia.

200

Pt has diabetes mellitus & metabolic acidosis. Which labs are correct? 1) pH 7.29, pCO2 35 mm HG, HCO3- 17 mmol/L 2) pH 7.31, pCO2 67 mm HG, HCO3- 32 mmol/L 3) pH 7.39, pCO2 43 mm HG, HCO3- 22 mmol/L 4) pH 7.45, pCO2 38 mm HG, HCO3- 23 mmol/L

1) pH 7.29, pCO2 35 mm HG, HCO3- 17 mmol/L The pH is below normal HCO3- below normal

300

pH 7.49, pCO2 41 mm HG, HCO3- 38 mmol/L Is the patient compensating? Metabolic alkalosis or acidosis?

Uncompensated metabolic alkalosis because an increase in pH, & an increase in HCO3, & PCO2 is normal

400

Which of the following is NOT a cause of metabolic acidosis? 1. Aspirin toxicity 2. Ileostomy 3. Hyperaldosteronism 4. Carbonic anhydrase inhibitors

3. Hyperaldosteronism 1. Aspirin toxicity-acid byproduct 2. Ileostomy loss of bicarbonate 4. Carbonic anhydrase inhibitors bicarbonate

500

A patient reports taking Diamox and has been reporting confusion, fatigue, and headaches. On assessment, you note the patient is exhibiting deep and rapid respirations. Which of the following arterial blood gas findings confirm the correct acid-base imbalance for this patient given their symptoms and medication usage? (Hint: Carbonic anhydrase inhibitors) 1. HCO3 12, pH 7.19, PaCO2 29 2. HCO3 23, pH 7.36, PaCO2 36 3. HCO3 10, pH 7.65, PaCO2 47 4. PaCO2 49, pH 7.55, HCO3 21

1. HCO3 12, pH 7.19, PaCO2 29 This patient is at risk for metabolic acidosis, especially since they are taking Diamox (Carbonic anhydrase inhibitors which reduces the reabsorption of bicarb). HCO3 12, pH 7.19, PaCO2 29 are the only ABGs that reflect metabolic acidosis.

Respiratory Alkalosis

100

The nurse notes that a client’s arterial blood gas results reveal a pH of 7.50 and a PCO2 of 30 mm Hg. The nurse monitors the client for which clinical manifestations associated with these arterial blood gas results? Select all that apply. 3. Bradypnea 4. Tachycardia 5. Hyperkalemia

4. Tachycardia Respiratory alkalosis is defined as a deficit of carbonic acid or a decrease in hydrogen ion concentration that results from the accumulation of base or from a loss of acid without a comparable loss of base in the body fluids. This occurs in conditions that cause overstimulation of the respiratory system. Clinical manifestations of respiratory alkalosis include lethargy, lightheadedness, confusion, tachycardia, dysrhythmias related to hypokalemia, nausea, vomiting, epigastric pain, and numbness and tingling of the extremities. Hyperventilation (tachypnea) occurs.

200

The nurse is caring for a client who is on a mechanical ventilator. Blood gas results indicate a pH of 7.50 and a Pco 2 of 30 mm Hg. The nurse has determined that the client is experiencing respiratory alkalosis. Which laboratory value will be noted in this condition? 1. Sodium level of 145 mEq/L 2. Potassium level of 3.0 mEq/L 3. Magnesium level of 2.0 mg/dL 4. Phosphorus level of 4.0 mg/dL

2. Potassium level of 3.0 mEq/L Respiratory alkalosis is defined as a deficit of carbonic acid or a decrease in hydrogen ion concentration that results from the accumulation of base or from a loss of acid without a comparable loss of base in the body fluids. This occurs in conditions that cause overstimulation of the respiratory system. Clinical manifestations of respiratory alkalosis include lethargy, lightheadedness, confusion, tachycardia, dysrhythmias related to hypokalemia, nausea, vomiting, epigastric pain, and numbness and tingling of the extremities. The correct option identifies the presence of hypokalemia.

300

Respiratory alkalosis can affect electrolyte levels in the body. What are the two main electrolytes is affected in this condition?

Potassium Calcium

400

A patient is experiencing respiratory alkalosis. What is the most classic sign and symptom of this condition? 1. Bradypnea 2. Tachypnea 3. Bradycardia 4. None of the options are correct

2. Tachypnea

500

A patient has the following blood gases: PaCO2 25, pH 7.50, HCO3 19. Which of the following could NOT be the cause of this condition? 1.Anxiety attack 2.Chronic obstructive pulmonary disease (COPD) 3.Fever 3.Aspirin toxicity

PaCO2 25, pH 7.50, HCO3 19. = Respiratory Alkalosis bc HCO3 & PaCO2 are low 2.Chronic obstructive pulmonary disease (COPD) as this would increase acidity

Respiratory Acidosis

100

The nurse reviews the blood gas results of a client with atelectasis. The nurse analyzes the results and determines that the client is experiencing respiratory acidosis. Which result validates the nurse’s findings? 1. pH 7.25, Pco 2 50 mm Hg 2. pH 7.35, Pco 2 40 mm Hg 3. pH 7.50, Pco 2 52 mm Hg 4. pH 7.52, Pco 2 28 mm Hg

1. pH 7.25, Pco 2 50 mm Hg Atelectasis is a condition characterized by the collapse of alveoli, preventing the respiratory exchange of oxygen and carbon dioxide in a part of the lungs. The normal pH is 7.35 to 7.45. The normal Pco 2 is 35 to 45 mm Hg. In respiratory acidosis, the pH is decreased and the Pco 2 is elevated. Option 2 identifies normal values.

200

In Respiratory Acidosis Ph is__ (high or low) PaCO2 is ___ (high or low) HCO3 is ___ (high or low)

In Respiratory Acidosis Ph is low PaCO2 is high HCO3 is high

300

A patient is experiencing respiratory acidosis due to brain trauma. Which of the following lab values correlates with this acid imbalance? 1. Potassium level of 6.0 2. Potassium level of 2.5 3. Potassium level of 5.0 4. Potassium level of 3.5

Potassium level of 6.0 In acidosis, the body protects itself from the acidic state by moving hydrogen ions into the cells. Therefore potassium moves out to make room for hydrogen ions and the potassium level increases.

400

Which patient is experiencing partially compensated respiratory acidosis? 1. PaCO2 30, pH 7.35, HCO3 26 2. PaCO2 53, pH 7.23, HCO3 28 3. PaCO2 45, pH 7.49, HCO3 21 4. PaCO2 50, pH 7.30, HCO3 23

PaCO2 53, pH 7.23, HCO3 28 Ph<7.35 high PaCO2 high HCO3

500

Which of the following is not a cause of respiratory acidosis? 1. Pulmonary emboli 2. Asthma 3. Chronic obstructive pulmonary disease (COPD) 4. Hyperventilation

4. Hyperventilation bc hyperventilation increases pH (more basic)