acid base balance: module 1 Flashcards
A client is brought to the emergency department (ED) after passing out in a local department store. The client has been fasting and has ketones in the urine. Which acid-base imbalance would the nurse expect to assess in this client?
A) Metabolic acidosis
B) Respiratory alkalosis
C) Metabolic alkalosis
D) Respiratory acidosis
A) Metabolic acidosis
A client who is fasting is at risk for development of metabolic acidosis. The body recognizes fasting as starvation and begins to metabolize its own fatty acids into ketones, which are metabolic acids. Starvation would not result in respiratory acidosis or alkalosis or in metabolic alkalosis.
Which risk factors exhibited by the client presenting in the emergency department (ED) would place the client at risk for metabolic acidosis? Select all that apply.
A) Abdominal fistulas
B) Chronic obstructive pulmonary disease
C) Pneumonia
D) Acute renal failure
E) Hypovolemic shock
A) Abdominal fistulas
D) Acute renal failure
E) Hypovolemic shock
Metabolic acidosis is rarely a primary disorder. It usually develops during the course of another disease; presence of abdominal fistulas, which can cause excess bicarbonate loss; acute renal failure; and hypovolemic shock. Chronic obstructive pulmonary disease and pneumonia place the client at risk for respiratory acidosis with the increased retention of carbon dioxide in the blood.
A child with acute asthma has a PaCO2 of 48 mmHg, a pH of 7.31, and a normal HCO3 blood gas value. The nurse interprets these findings as indicative of which condition?
A) Metabolic acidosis
B) Respiratory alkalosis
C) Respiratory acidosis
D) Metabolic alkalosis
C) Respiratory acidosis
If the pH is decreased and the PaCO2 is increased with a normal HCO3, it is uncompensated respiratory acidosis. Uncompensated respiratory alkalosis has an increased pH, decreased PaCO2, and normal HCO3. Uncompensated metabolic acidosis has a decreased pH, normal PaCO2, and decreased HCO3. Uncompensated metabolic alkalosis has an increased pH, normal PaCO2, and increased HCO3.
The nurse is reviewing the latest arterial blood gas results for a client with metabolic alkalosis. Which result indicates that the metabolic alkalosis is compensated?
A) pH 7.32
B) PaCO2 18 mmHg
C) HCO3 8 mEq/L
D) PaCO2 48 mmHg
D) PaCO2 48 mmHg
A normal pH level is 7.35-7.45. A pH of less than 7.35 is acidosis. A PaCO2 level of 18 mmHg is low and is seen in respiratory alkalosis. A HCO3 level of 8 mEq/L is low and is most likely associated with metabolic acidosis. In metabolic alkalosis, there is an excess of bicarbonate. To compensate for this imbalance, the rate and depth of respirations decrease, leading to retention of carbon dioxide. The PaCO2 will be elevated.
A client has been admitted with chronic obstructive pulmonary disease. Diagnostic tests have been ordered. Which of the tests will provide the most accurate indicator of the client’s acid-base balance?
A) Arterial blood gases (ABGs)
B) Pulse oximetry
C) Sputum studies
D) Bronchoscopy
A) Arterial blood gases (ABGs)
ABGs are done to assess alterations in acid-base balance caused by respiratory disorders, metabolic disorders, or both. A bronchoscopy provides visualization of internal respiratory structures. Sputum studies can provide specific information about bacterial organisms. Pulse oximetry is a noninvasive test that evaluates the oxygen saturation level of blood.
The nurse is instructing a client with a history of acidosis on the use of sodium bicarbonate. Which client statement indicates that additional teaching is needed?
A) “I should contact the doctor if I have any gastric discomfort with chest pain.”
B) “I need to purchase antacids without salt.”
C) “I should use the antacid for at least 2 months.”
D) “I should call the doctor if I get short of breath or start to sweat with this medication.”
C) “I should use the antacid for at least 2 months.”
The client should be instructed to immediately contact the primary healthcare provider if gastric discomfort occurs with chest pain or if dyspnea or diaphoresis occurs. The client should be instructed to use non-sodium antacids to prevent the absorption of excess sodium or bicarbonate into systemic circulation and to not use any bicarbonate antacid for longer than 2 weeks.
The client is receiving sodium bicarbonate intravenously (IV) for correction of acidosis secondary to diabetic coma. The nurse assesses the client to be lethargic, confused, and breathing rapidly. Which is the nurse’s priority response to the current situation?
A) Stop the infusion and notify the physician because the client is in alkalosis.
B) Decrease the rate of the infusion and continue to assess the client for symptoms of alkalosis.
C) Continue the infusion, because the client is still in acidosis, and notify the healthcare provider.
D) Increase the rate of the infusion and continue to assess the client for symptoms of acidosis.
C) Continue the infusion, because the client is still in acidosis, and notify the healthcare provider.
The client receiving sodium bicarbonate is prone to alkalosis; monitor for cyanosis, slow respirations, and irregular pulse. The client’s symptoms do not indicate alkalosis so infusion should not be stopped. The client continues to exhibit signs of acidosis; symptoms of acidosis include lethargy, confusion, CNS depression leading to coma, and a deep, rapid respiration rate that indicates an attempt by the lungs to rid the body of excess acid, and the physician should be notified. The infusion should not be increased or decreased without a practitioner order.
The nurse is preparing to analyze a client’s arterial blood gas results. List the steps in the order that the nurse should follow when analyzing this laboratory test.
- Look at the PaCO2.
- Look at the pH.
- Evaluate the relationship between pH and PaCO2.
- Look for compensation.
- Evaluate the pH, HCO3, and base excess for a possible metabolic problem.
- Look at the bicarbonate.
- Evaluate oxygenation
Answer: 2, 1, 3, 6, 5, 4, 7
- The second step is to look at the PaCO2. If the PaCO2 is <35, then more carbon dioxide is being exhaled. If the PaCO2 is >45, then more carbon dioxide is being retained.
- The pH is the first step and is analyzed to determine if acidosis or alkalosis is present. A pH of <7.35 is acidosis. A pH of >7.45 is alkalosis.
- The third step is to evaluate the relationship between the pH and the PaCO2. This relationship could indicate a respiratory problem. If the pH is acidotic and the carbon dioxide level is greater than 45, then the client could be experiencing respiratory acidosis. If the pH is alkalotic and the carbon dioxide level is below 35, then the client could be experiencing respiratory alkalosis.
- The sixth step is to look for compensation. Two things can occur in renal compensation. In respiratory acidosis, the kidneys retain HCO3 to buffer the excess acid, so the HCO3 is >26 mEq/L. In respiratory alkalosis, the kidneys excrete HCO3 to minimize the alkalosis, so the HCO3 is <22 mEq/L. Two things can also occur in respiratory compensation. In metabolic acidosis, the rate and depth of respirations increase, increasing carbon dioxide elimination, so the PaCO2 is <35 mmHg. In metabolic alkalosis, respirations slow and carbon dioxide is retained, so the PaCO2 is >45 mmHg.
- The fifth step is to evaluate the pH, HCO3, and base excess for a possible metabolic problem. If the pH is <7.35, the HCO3 is <22 mEq/L, and the BE is less than −3 mEq/L, then low bicarbonate levels and high H+ concentrations are causing metabolic acidosis. If the pH is >7.45, the HCO3 is >26 mEq/L, and the BE is greater than +3 mEq/L, then high bicarbonate levels are causing metabolic alkalosis.
- The fourth step is to look at the bicarbonate level. If the bicarbonate level is <22, then the levels are lower than normal. If the bicarbonate level is > 26, then the bicarbonate levels are higher than normal.
7.The final step is to evaluate oxygenation. If the PaO2is <80 mmHg, then the client is experiencing hypoxemia and possible hypoventilation. If the PaO2is >100 mmHg, then the
The nurse is identifying a diagram to use to explain a client’s acid-base balance. Which imbalance does the following diagram suggest is occurring with the client?
A) Metabolic acidosis
B) Metabolic alkalosis
C) Respiratory acidosis
D) Respiratory alkalosis
A) Metabolic acidosis
In metabolic acidosis, the amount of bicarbonate decreases in relation to the amount of acid in the body. In metabolic alkalosis, there is an excess of bicarbonate in relation to the amount of hydrogen ions. Respiratory acidosis occurs when carbon dioxide is retained, increasing the amount of carbonic acid in the body. Respiratory alkalosis can occur when too much carbon dioxide is lost and carbonic acid levels fall.
The results of a client’s arterial blood gas sample reveal an oxygen level of 72 mmHg. For which associated health problem should the nurse assess this client?
A) Stress and coping
B) Perfusion
C) Fluid and electrolyte imbalance
D) Cognition
D) Cognition
An oxygen level of less than 75 mmHg can be due to hypoventilation. This drop in oxygen will change the client’s level of responsiveness. Perfusion is affected by a reduction in circulating fluids. With a fluid and electrolyte imbalance, there is another disorder affecting acid-base balance. This might not be affected by oxygen level. Stress and coping may need to be analyzed to determine how the client is coping with the anxiety related to low oxygen levels, but this is not directly a physiological health problem.
The nurse is caring for a comatose client with metabolic acidosis. For which intervention will the nurse need to collaborate when caring for this client?
A) Measuring vital signs
B) Measuring intake and output
C) The client’s recent eating behaviors
D) Identifying current oxygen saturation level
C) The client’s recent eating behaviors
For clients in severe distress, family members may need to be consulted for critical information such as recent eating habits and history of vomiting. Measuring vital signs, measuring intake and output, and identifying current oxygen saturation level are independent nursing actions.
Acid-base balance is critical to homeostasis and cellular function. One measurement of acid-base balance is the pH of the blood. Which ion is measured to determine the pH?
A) Cl-
B) H+
C) Na+
D) HCO3
B) H+
The pH measures the concentration of hydrogen ions (H+) in the body. Sodium (Na+) and chloride (Cl-) concentrations are not related to pH. Bicarbonate (HCO3) is a weak base that is used as a buffer to help maintain the proper pH, but it is not used to measure pH.
A client with a suspected acid-base imbalance has arterial blood gases tested. The test reveals a serum bicarbonate level of 22 mEq/L. The nurse understands that this bicarbonate level is
A) slightly high.
B) slightly low.
C) extremely high.
D) within normal range.
B) slightly low.
The normal serum bicarbonate level is 24-28 mEq/L. Therefore, the nurse would understand that the client’s bicarbonate level is slightly low.
If a change in acid-base balance is due to hypoventilation or hyperventilation, the nurse will need to primarily focus on which concept related to acid-base balance?
A) Oxygenation
B) Perfusion
C) Cognition
D) Stress and coping
A) Oxygenation
Hypoventilation and hyperventilation are related to oxygenation. Respiratory rate helps regulate carbon dioxide pressures, which can contribute to acidosis or alkalosis. The nurse can help reverse respiratory acidosis or alkalosis by helping the client control their respiratory rate to restore normal oxygenation. Perfusion, cognition, and stress and coping do not directly relate to hypo- or hyperventilation.
When considering acid-base balance, health promotion should focus on
A) conducting yearly health screenings.
B) obtaining immunizations.
C) beginning an exercise regimen.
D) maintaining fluid balance.
D) maintaining fluid balance.
Both overhydration and dehydration can result in acid-base imbalances. Therefore, health promotion should focus on maintaining fluid balance. Beginning an exercise regimen, obtaining immunizations, and conducting yearly health screenings are activities that can promote health in other areas.
