Test 4 acid base 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
Answer: A
Rationale: 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
Answer: A, D, E
Rationale: 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
Answer: C
Rationale: 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
Answer: D
Rationale: 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
Answer: A
Rationale: 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.”
Answer: C
Rationale: 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.
Answer: C
Rationale: 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.
- The final step is to evaluate oxygenation. If the PaO2 is <80 mmHg, then the client is experiencing hypoxemia and possible hypoventilation. If the PaO2 is >100 mmHg, then the client is hyperventilating.
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
Answer: D
Rationale: 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
Answer: C
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
Answer: B
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.
B) 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.
Answer: B
Rationale: 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
Answer: A
Rationale: 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.
Answer: D
Rationale: 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.
The nurse performing a blood draw for arterial blood gases first performs a modified Allen test for what purpose?
A) To reduce the risk of bleeding or bruising of the arm
B) To determine if arterial puncture can safely be performed
C) To determine the oxygen saturation of the blood in the artery
D) To determine the pressure of the blood in the artery
Answer: B
Rationale: A modified Allen test is a measure of ulnar patency. The patient elevates the hand and repeatedly makes a fist while the examiner places digital occlusive pressure over the radial and ulnar arteries of the wrist. The hand will lose its normal color. Digital pressure is released from one artery while the other remains compressed. The return of color indicates that the hand has good collateral supply of blood and that arterial puncture can safety be performed. The modified Allen test does not measure oxygen saturation or artery pressure, and it does not reduce the risk of bleeding or bruising.
An intervention that can be implemented independently by the nurse caring for a client with an acid-base balance is
A) monitoring intake and output.
B) drawing blood for ABGs.
C) giving sodium bicarbonate infusions.
D) administering oxygen via nasal cannula.
Answer: A
Rationale: Monitoring intake and output is an independent nursing intervention that does not require a provider’s orders. Drawing blood for ABGs, giving sodium bicarbonate infusions, and administering oxygen via nasal cannula are all actions that can be performed by the nurse, but they must first be ordered by a provider.
Why should a nurse take daily weights of a client with acid-base balance?
A) It helps monitor oxygenation status.
B) It helps monitor perfusion of organs.
C) It helps monitor renal function.
D) It helps monitor fluid balance.
Answer: D
Fluid balance must be maintained to support acid-base balance. If a client rapidly gains weight, it is a sign of fluid overload. If a client rapidly loses weight, it is a sign of dehydration. Both of these conditions can alter the acid-base balance, so a client’s weight should be monitored daily. A client’s weight does not reflect oxygenation status or perfusion of organs. Daily weights can reflect renal function, but weight can fluctuate even if the kidneys are functioning properly.
The nurse is analyzing the client’s arterial blood gas report, which reveals a pH of 6.58. The client has just suffered a cardiac arrest. Which consequences of this pH value does the nurse consider for this client?
A) Decreased cardiac output
B) Increase magnesium levels
C) Decreased free calcium in the ECT
D) Increased myocardial contractility
Answer: A
Rationale: The nurse knows that severe acidosis (pH of 7.0 or less) depresses myocardial contractility, which leads to decreased cardiac output. Acid-base imbalances also affect electrolyte balance. In acidosis, calcium is released from its bonds with plasma proteins, increasing the amount of ionized (free) calcium in the blood. Magnesium levels may fall in acidosis.
The nurse is caring for a client who has been admitted with persistent diarrhea lasting 3 days. Which are appropriate nursing diagnoses for this client during the acute phase of the illness? Select all that apply.
A) Decreased Cardiac Output B) Ineffective Airway Clearance C) Overflow Urinary Incontinence D) Knowledge Deficit E) Risk for Injury
Answer: A, E
Rationale: Metabolic acidosis decreases cardiac output by decreasing contractility, slowing the heart rate, and increasing the risk for dysrhythmias. The client with metabolic acidosis is also at risk for injury due to altered mental status. Appropriate nursing diagnoses during the acute phase of illness are Risk for Injury and Decreased Cardiac Output. The client may have a knowledge deficit, but this is not an appropriate nursing diagnosis during the acute phase of the illness. The client with metabolic acidosis is not at risk for Ineffective Airway Clearance or Overflow Urinary Incontinence.
The nurse is caring for a client with metabolic acidosis. Which goals are appropriate for this client? Select all that apply.
A) The client will maintain a respiratory rate of 30 or more.
B) The client will describe preventative measure for the underlying chronic illness.
C) The client will maintain baseline cardiac rhythm.
D) The client will remain in a pH range from 7.25 to 7.35.
E) The client will take potassium supplements to increase potassium levels.
Answer: B, C
Planning for the client with metabolic acidosis involves identification and treatment of the underlying cause and restoration and maintenance of acid-base balance. The client should be able to describe preventative measures for the underlying chronic illness that caused the metabolic acidosis to occur and maintain the baseline cardiac rhythm. The pH should be maintained between 7.35 and 7.45. The client’s respiratory rate should be within normal range for age and condition. Taking a potassium supplement may cause hyperkalemia, which decreases cardiac output and worsens metabolic acidosis.
The nurse is caring for a client admitted with renal failure and metabolic acidosis. Which clinical manifestation would indicate to the nurse that planned interventions to relieve the metabolic acidosis have been effective?
A) Decreased respiratory depth
B) Palpitations
C) Increased deep tendon reflexes
D) Respiratory rate of 38
Answer: A
Rationale: The client with metabolic acidosis will have an increased respiratory rate and depth, called Kussmaul respirations. Signs that care has been effective would include a decrease in the rate and depth of respirations. An increased respiratory rate, as indicated by a respiratory rate of 38, would indicate continued metabolic acidosis. Increased deep tendon reflexes and palpitations are not associated with metabolic acidosis.
The nurse is caring for the client experiencing hypovolemic shock and metabolic acidosis. Which therapies would the nurse question if planned for this client? Select all that apply.
A) Monitor weight on admission and discharge.
B) Monitor ECG for conduction problems.
C) Limit the intake of fluids.
D) Administer sodium bicarbonate.
E) Keep the bed in the locked and low position.
Answer: A, C
Rationale: The treatment for hypovolemic shock would include the administration of fluids, not limiting fluids. Patients being treated for hypovolemia and metabolic acidosis will require daily weights, not a weight on admission and then discharge. Administering sodium bicarbonate and monitoring ECGs are appropriate for the client with metabolic acidosis. The client recovering from hypovolemic shock and metabolic acidosis is at risk for injury, so the bed should be kept in the locked and low position.
A client with metabolic acidosis has been admitted to the unit from the emergency department (ED). The client is experiencing confusion and weakness. Which nursing intervention is the priority for this client?
A) Placing the client in a high-Fowler position
B) Protecting the client from injury
C) Administering sodium bicarbonate
D) Providing the client with appropriate skin care
Answer: B
Rationale: The client with metabolic acidosis may have symptoms of drowsiness, lethargy, confusion, and weakness. A priority of care would be preventing injury to the client. Medication administration is a physician order. Skin care would not be a priority on admission. The high-Fowler position would not be the safest position for the confused client.
The nurse is preparing to teach a client with type 1 diabetes mellitus on the mechanism behind the development of ketoacidosis. List the order in which the nurse should provide this information.
- Production of lactate and hydrogen ions
- Tissue hypoxemia
- Breakdown of fatty tissue
- Reduction in intracellular glucose
- Fatty acids converted to ketones
Answer: 2, 1, 4, 3, 5
Rationale: Lactic acidosis develops due to tissue hypoxia and a shift to anaerobic metabolism by the cells. Lactate and hydrogen ions are produced, forming lactic acid. Starvation or lack of insulin leads to intracellular starvation of glucose. The lack of glucose or insulin to move glucose into the cells, causing the body to break down fatty tissue to meet metabolic needs. When fatty acids are broken down, these acids are converted to ketones, leading to the development of ketoacidosis.
The nurse identifies the diagnosis Risk for Injury as appropriate for a client with metabolic acidosis. Which strategies should the nurse use to support this diagnosis? Select all that apply.
A) Apply wrist restraints and secure to the bed frame.
B) Discuss chemical restraint use with the healthcare provider.
C) Keep the bed in the lowest position.
D) Keep bed side rails raised.
E) Place a clock and calendar at the bedside.
Answer: C, D, E
Rationale: To reduce the client’s risk for injury, the nurse should make sure the bed is kept in the lowest position and the side rails are raised. A clock and calendar at the bedside will help with orientation. Restraints are used in the event the client demonstrates harm to self or others. Confusion or a risk for injury is not a reason to use wrist or chemical restraints.
Upon entering a room, the nurse quickly scans the environment and then immediately assesses the client for manifestations of metabolic acidosis. Which did the nurse observe to precipitate this client assessment?
A) Client sleeping with the head of the bed flat
B) Half of the client’s lunch tray uneaten
C) One formed stool in the bedside commode
D) 2000 mL of intravenous 0.9% normal saline infused in 2 hours
Answer: D
Rationale: Excessive infusions of chloride-containing intravenous fluids can precipitate metabolic acidosis. The head of the bed’s being flat might influence a client’s oxygenation status; however, the client was not demonstrating a change in respiratory depth or rate. A reduction in oral intake does not cause metabolic acidosis. Eating half of a meal tray is not the same as starvation. Diarrhea can lead to the development of metabolic acidosis. One formed stool would not cause the nurse alarm.
During a home visit, the nurse evaluates care provided to a client with type 1 diabetes mellitus and a history of metabolic acidosis. Which outcome indicates that the care of this client has been successful?
A) The client is injecting insulin into thigh muscle.
B) The client is taking laxatives three times a week to ensure adequate bowel movements.
C) The client is eating three balanced meals per day with two snacks.
D) The client is taking aspirin 325 mg every 6 hours to treat arthritis pain.
Answer: C
Rationale: Adequate nutrition is necessary to prevent the buildup of acids in the blood. Incorrect administration of medication could cause a metabolic problem in the client with diabetes. The use of laxatives could cause diarrhea, which can lead to metabolic acidosis. Ingestion of high amounts of salicylate acid can lead to toxicity and the development of metabolic acidosis.
A common cause of metabolic acidosis is
A) hyperventilation in a client with anxiety.
B) high blood glucose in a client with type 1 diabetes.
C) vomiting in a client with a gastrointestinal infection.
D) opiate overdose in a client with depression.
Answer: B
Rationale: High blood glucose that leads to diabetic ketoacidosis is a common cause of metabolic acidosis. Vomiting can lead to metabolic alkalosis, hyperventilation can lead to respiratory alkalosis, and opiate overdose can lead to respiratory acidosis.
A compensatory mechanism that may indicate to a nurse that a client is experiencing metabolic acidosis includes:
A) headache.
B) Kussmaul respirations.
C) vomiting.
D) decreased level of consciousness.
Answer: B
Rationale: Kussmaul respirations are deep and rapid respirations that are a compensatory mechanism during metabolic acidosis. Headache, vomiting, and decreased level of consciousness are all clinical manifestations of metabolic acidosis, but they are not compensatory mechanisms that the body uses to maintain acid-base balance during metabolic acidosis.
An alkalinizing solution often given intravenously to clients with severe acute metabolic acidosis is
A) sodium bicarbonate.
B) sodium chloride.
C) potassium chloride.
D) dextrose.
Answer: A
Rationale: Sodium bicarbonate is an alkalinizing solution often given intravenously to clients with severe acute metabolic acidosis. Sodium chloride and potassium chloride may worsen metabolic acidosis by increasing the chloride concentration. Dextrose may also worsen metabolic acidosis, especially in clients with type 1 diabetes, by increasing blood glucose levels and causing ketoacidosis.
The nurse is caring for a 3-month-old infant who presented to the emergency department (ED) with fever, diarrhea, vomiting, and diaper rash over the past 48 hours. Which symptom puts this client most at risk for metabolic acidosis?
A) Fever
B) Diarrhea
C) Vomiting
D) Diaper rash
Answer: B
Rationale: Infants are more susceptible to metabolic acidosis from diarrhea due to significant losses of bicarbonate in the feces. Vomiting is more likely to result in metabolic alkalosis from loss of stomach acids. Fever and diaper rash do not directly contribute to metabolic acidosis.