1. In a client with less than the normal amount of bicarbonate in the blood and other extracellular fluids, what response does the nurse anticipate?

a.            Increased risk for acidosis

b.            Decreased risk for acidosis

c.             Increased risk for alkalosis

d.            Decreased risk for alkalosis

ANS: A

Bicarbonate (H2CO3–) is a weak base with an overall negative charge. When hydrogen ions are present in slight or mild excess (mild acidosis), bicarbonate can buffer or absorb the excess hydrogen ions, reducing the hydrogen ion concentration and bringing the pH back up to normal. If the total body bicarbonate concentration is low, especially in the blood, the action of buffering or absorbing excess hydrogen ions is reduced, and the person is at increased risk for acidosis.

DIF: Cognitive Level: Comprehension/Understanding REF: p. 202

TOP: Client Needs Category: Physiological Integrity (Physiological Adaptation—Pathophysiology)

MSC: Integrated Process: Nursing Process (Assessment)

2. Which response is an example of compensation for an acid-base imbalance?

a.            Increase in the rate and depth of respirations when exercising

b.            Increased urinary output when blood pressure increases during exercise

c.             Increased thirst when spending time in an excessively dry environment

d.            Increased release of acids from kidneys during exacerbation of chronic obstructive pulmonary disease (COPD)

ANS: A

The respiratory system increases its activity by blowing off excess carbon dioxide. This occurs as a result of the occurrence of lactic acidosis in skeletal muscle, when blood flow and oxygenation are insufficient to meet the increased demand for oxygen (oxygen debt) created during increased skeletal muscle metabolism. The other three options are not compensatory mechanisms for acid-base imbalances.

DIF: Cognitive Level: Comprehension/Understanding REF: p. 200

TOP: Client Needs Category: Physiological Integrity (Physiological Adaptation—Pathophysiology)

MSC: Integrated Process: Nursing Process (Assessment)

3. When a client has an arterial blood pH of 7.48, which buffer action will bring the pH back to normal?

a.            Absorption of bicarbonate ions from the blood

b.            Release of bicarbonate ions into the blood

c.             Absorption of hydrogen ions from the blood

d.            Release of hydrogen ions into the blood

ANS: D

Buffers can act as an acid (releasing a hydrogen ion) or as a base (absorbing a hydrogen ion) to assist in keeping the pH and hydrogen ion concentration of body fluids within the normal range. An arterial pH of 7.48 indicates a deficiency of hydrogen ions. This situation would cause buffers to act like acids and release hydrogen ions into the blood.

DIF: Cognitive Level: Comprehension/Understanding REF: p. 200

TOP: Client Needs Category: Physiological Integrity (Physiological Adaptation—Pathophysiology)

MSC: Integrated Process: Nursing Process (Analysis)

4. A client has moderate acidosis. Which assessment does the nurse perform first?

a.            Take the client’s pulse and blood pressure, and analyze the electrocardiogram (ECG) strip.

b.            Assess respiratory rate and depth and work of breathing.

c.             Perform assessments of musculoskeletal strength.

d.            Determine whether the client is awake, alert, and oriented.

ANS: A

Priority assessments for the client with acidosis relate to the cardiovascular system. Acidosis can lead to lethal cardiac dysrhythmias.

DIF: Cognitive Level: Application/Applying or higher REF: N/A

TOP: Client Needs Category: Safe and Effective Care Environment (Management of Care—Establishing Priorities) MSC: Integrated Process: Nursing Process (Assessment)

5. In the client with hypoventilation, which change in arterial blood gases does the nurse evaluate to determine whether treatment measures are being effective?

a.            Decreased arterial blood pH

b.            Decreased arterial blood carbon dioxide

c.             Increased arterial blood bicarbonate

d.            Increased arterial blood oxygen

ANS: C

Because kidneys regulate pH by controlling bicarbonate concentration and the lungs regulate pH by controlling carbon dioxide loss, loss of one function can be at least partially compensated for by the other function. When pulmonary function is decreased, so that adequate amounts of carbon dioxide are not excreted, the pH falls, stimulating the kidneys to reabsorb more bicarbonate to balance the increased acid production.

DIF: Cognitive Level: Application/Applying or higher REF: N/A

TOP: Client Needs Category: Physiological Integrity (Physiological Adaptation—Pathophysiology)

MSC: Integrated Process: Nursing Process (Evaluation)

6. In a client 4 minutes post cardiac arrest, the nurse correlates the largest source of excess hydrogen ions with which cause?

a.            Excess renal retention of carbon dioxide due to hypoxia

b.            Release of intracellular acids due to widespread tissue destruction

c.             Anaerobic metabolism, leading to the buildup of lactic acid

d.            Using fat as a fuel source, resulting in increased fat degradation

ANS: C

Glucose metabolism continues under anaerobic conditions to supply the body with chemical energy (adenosine triphosphate [ATP]). However, this metabolism is incomplete, stopping at lactic acid production instead of continuing into the Krebs’ cycle. This results in a large buildup of lactic acid, which releases excessive amounts of hydrogen ions into the blood.

DIF: Cognitive Level: Comprehension/Understanding REF: p. 202

TOP: Client Needs Category: Physiological Integrity (Physiological Adaptation—Pathophysiology)

MSC: Integrated Process: Nursing Process (Analysis)

7. A client has mild acidosis but after a day has not compensated for it. Which action by the nurse is best?

a.            Review the client’s daily hemoglobin and hematocrit.

b.            Ask the laboratory to rerun today’s arterial blood gases.

c.             Document the finding and notify the physician.

d.            Apply 2 L of oxygen via nasal cannula.

ANS: A

Hemoglobin is part of the buffering system. Low hemoglobin affects acid-base balance by decreasing the body’s ability to compensate for mild acidosis. Rerunning the specimen would take time and might require another sample. The nurse may need to notify the physician but would need more information to report, such as hemoglobin and hematocrit values. Adding 2 liters of oxygen would not help the client as much as he or she would be helped if the cause of the refractory acidosis was determined.

DIF: Cognitive Level: Application/Applying or higher REF: N/A

TOP: Client Needs Category: Physiological Integrity (Physiological Adaptation—Pathophysiology)

MSC: Integrated Process: Nursing Process (Implementation)