Acid & Base PrepU N400
In chronic obstructive pulmonary disease (COPD), decreased carbon dioxide elimination results in increased carbon dioxide tension in arterial blood, leading to which of the following acid-base imbalances? Respiratory acidosis Respiratory alkalosis Metabolic alkalosis Metabolic acidosis
Respiratory acidosis Explanation: Increased carbon dioxide tension in arterial blood leads to respiratory acidosis and chronic respiratory failure. In acute illness, worsening hypercapnia can lead to acute respiratory failure. The other acid-base imbalances would not correlate with COPD.
A client comes to the emergency department with status asthmaticus. His respiratory rate is 48 breaths/minute, and he is wheezing. An arterial blood gas analysis reveals a pH of 7.52, a partial pressure of arterial carbon dioxide (PaCO2) of 30 mm Hg, PaO2 of 70 mm Hg, and bicarbonate (HCO3??') of 26 mEq/L. What disorder is indicated by these findings? Metabolic acidosis Respiratory acidosis Metabolic alkalosis Respiratory alkalosis
Respiratory alkalosis Explanation: Respiratory alkalosis results from alveolar hyperventilation. It's marked by a decrease in PaCO2 to less than 35 mm Hg and an increase in blood pH over 7.45. Metabolic acidosis is marked by a decrease in HCO3? to less than 22 mEq/L, and a decrease in blood pH to less than 7.35. In respiratory acidosis, the pH is less than 7.35 and the PaCO2 is greater than 45 mm Hg. In metabolic alkalosis, the HCO3? is greater than 26 mEq/L and the pH is greater than 7.45.
Which of the following clients is at highest risk for peptic ulcer disease? Client with blood type A Client with blood type B Client with blood type AB Client with blood type O
Client with blood type O Explanation: Clients with blood type O are more susceptible to peptic ulcers than those with blood types A, B, and AB.
A client has been diagnosed with metabolic acidosis. What assessment finding does the nurse expect? Increased pH above 7.45 Increased PCO2 above 45 mm/Hg (5.99 kPa) Decreased pH below 7.35 Decreased PCO2 below 35 mm/Hg (4.66 kPa)
Decreased pH below 7.35 Explanation: In metabolic acidosis, the client's pH will decrease below 7.35 or normal range. In addition , the client's HCO3- will decrease to below 22 mEq/L (22 mmol/L)
A client in the emergency department reports that they have been vomiting excessively for the past 2 days. The client's arterial blood gas analysis shows a pH of 7.50, partial pressure of arterial carbon dioxide (PaCO2) of 43 mm Hg, partial pressure of arterial oxygen (PaO2) of 75 mm Hg, and bicarbonate (HCO3-) of 42 mEq/L. Based on these findings, the nurse documents that the client is experiencing which type of acid-base imbalance? respiratory alkalosis metabolic alkalosis respiratory acidosis metabolic acidosis
metabolic alkalosis Explanation: A pH over 7.45 with a HCO3- level over 26 mEq/L indicates metabolic alkalosis. Metabolic alkalosis is always secondary to an underlying cause and is marked by decreased amounts of acid or increased amounts of base HCO3-. The client isn't experiencing respiratory alkalosis because the PaCO2 is normal. The client isn't experiencing respiratory or metabolic acidosis because the pH is greater than 7.35.
A client is receiving supplemental oxygen. When determining the effectiveness of oxygen therapy, which arterial blood gas value is most important? pH bicarbonate (HCO3-) partial pressure of arterial oxygen (PaO2) partial pressure of arterial carbon dioxide (PaCO2)
partial pressure of arterial oxygen (PaO2) Explanation: The most significant and direct indicator of the effectiveness of oxygen therapy is the PaO2 value. Based on the PaO2 value, the nurse may adjust the type of oxygen delivery (cannula, Venturi mask, or mechanical ventilator), flow rate, and oxygen percentage. The other options reflect the client's ventilation status, not oxygenation. The pH, HCO3-, and PaCO2
A client tells the nurse that the client has been taking Alka-Seltzer (bicarbonate—antacid) four times a day for the past 2 weeks for an upset stomach. Upon assessment of the client, the nurse notes hyperactive reflexes, tetany, and mental confusion. Arterial blood gases reveal pH 7.55; serum HCO3− 37 mEq/L (37 mmol/L). The nurse suspects the client may be experiencing: Metabolic alkalosis Respiratory acidosis Metabolic acidosis Respiratory alkalosis
Metabolic alkalosis Explanation: Metabolic alkalosis is characterized by a serum pH greater than 7.45; serum HCO3− greater than 29 mEq/L (29 mmol/L); and a base excess greater than 3.0. Transient or acute alkalosis is common during or immediately following excess oral ingestion of bicarbonate antacids. Respiratory acidosis as well as metabolic acidosis would have a decrease in pH. Respiratory alkalosis would have an increase in pH and a HCO3− less than 24 mEq/L (24 mmol/L).
A client is admitted to the health care center with abdominal pain, nausea, and vomiting. The medical reports indicate a history of type 1 diabetes. The nurse suspects the client's symptoms to be those of diabetic ketoacidosis (DKA). Which action will help the nurse confirm the diagnosis? Assess the client's ability to take a deep breath Assess the client's ability to move all extremities Assess the client's breath odor Assess for excessive sweating
Assess the client's breath odor Explanation: DKA is commonly preceded by a day or more of polyuria, polydipsia, nausea, vomiting, and fatigue, with eventual stupor and coma if not treated. The breath has a characteristic fruity odor due to the presence of ketoacids. Checking the client's breath will help the nurse confirm the diagnosis.
A nurse reviews the arterial blood gas (ABG) values of a client admitted with pneumonia: pH, 7.51; PaCO2, 28 mm Hg; PaO2, 70 mm Hg; and HCO3--, 24 mEq/L. What do these values indicate? Metabolic acidosis Metabolic alkalosis Respiratory acidosis Respiratory alkalosis
Respiratory alkalosis Explanation: A client with pneumonia may hyperventilate in an effort to increase oxygen intake. Hyperventilation leads to excess carbon dioxide (CO2) loss, which causes alkalosis — indicated by this client's elevated pH value. With respiratory alkalosis, the kidneys' bicarbonate (HCO3-) response is delayed, so the client's HCO3- level remains normal. The below-normal value for the partial pressure of arterial carbon dioxide (PaCO2) indicates CO2 loss and signals a respiratory component. Because the HCO3- level is normal, this imbalance has no metabolic component. Therefore, the client is experiencing respiratory alkalosis.
When explaining the body's compensatory mechanisms to maintain a normal pH, the health care provider knows that the renal system: works slower than the respiratory system, going into action 1 to 2 days after H+ remain elevated. will absorb more bile acids to try to normalize elevated H+ levels. will absorb more Na+ and water to dilute the elevated H+ in an effort to normalize pH. waits until the lungs have increased the respiratory rate to try to blow off excess CO2.
works slower than the respiratory system, going into action 1 to 2 days after H+ remain elevated. Explanation: Only the kidney can eliminate hydrogen from the body. Virtually all the excess H+ excreted in the urine are secreted into the tubular fluid by means of tubular secretory mechanisms. The ability of the kidneys to excrete large amounts of H+ in the urine is accomplished by combining the excess ions with buffers in the urine. The three major urine buffers are bicarbonate (HCO3−), phosphate (HPO42−), and ammonia (NH3). An important aspect of this buffer system is that the deamination process increases whenever the body's hydrogen ion concentration remains elevated for 1 to 2 days.
The nurse is caring for a client in active labor who has had a fetal blood sampling to check for fetal hypoxia. The nurse determines that the fetus has acidosis when the pH is: 7.15 or less. 7.25 or more. 7.20. 7.21.
7.15 or less. Explanation: In the hypoxic fetus, the pH will fall below 7.2, which is indicative of fetal distress
A client who is blind is admitted for treatment of a small bowel obstruction and has been vomiting for days. Which nursing diagnosis takes highest priority for this client? Deficient fluid volume Risk for injury Activity intolerance Impaired physical mobility
Deficient fluid volume Explanation: Although the client's disability should be considered in the course of assessment and delivery of health and nursing care, it should not become the overriding focus or exclusive focus of the assessment or the care that the client receives. Because the client has been vomiting for days, he is most likely dehydrated; therefore, deficient fluid volume takes highest priority. A sensory deficit such as blindness puts the client at risk for injury from the environment; however, a potential problem doesn't take highest priority.
A client has these arterial blood gas values: anion gap 20 mEq/L (20 mmol/L), pH 7.29, PCO2 37 mm Hg (4.92 mmol/L), HCO3- 11 mEq/L (11 mmol/L), base excess -6 mEq/L (-6 mmol/L). With what condition do these values correspond? Lactic acidosis Hyperkalemia Multiple myeloma lithium toxicity
Lactic acidosis Explanation: Anion gap (AG) is the difference between the plasma concentration of sodium ions and the sum of the measured anions (chloride and bicarbonate). Normally, the AG value should be between 8 and 16 mEq/L. AG will rise above normal for conditions that commonly cause acidosis such as lactic acidosis and ketoacidosis. Hyperkalemia, lithium toxicity, hypercalcemia, hypermagnesemia, and multiple myeloma will cause a drop in the AG by raising the level of unmeasured cations. ABGs measure pH, carbon dioxide (PCO2), bicarbonate ion (HCO3-), oxygen (PO2), base excess, and the anion gap. A pH that is below 7.35 is considered acidic. The PCO2 is the primary indicator of respiratory function and falls between 35 and 45mm Hg. Bicarbonate (HCO3-) is the primary indicator of metabolic function and is acidic if below 22 mEq/L. Base excess measures the level of all the buffer systems in the blood. If the level is more than 0.2 mEq/L below the normal pH of 7.4 it is considered deficit and indicates metabolic acidosis.
A nurse working in the emergency department (ED) reviews arterial blood gas (ABG) values for a patient diagnosed with heatstroke. Blood gas values are pH 7.48, pCO2 34, pO2 95, CO2 23, HCO2 22, and SO298%. Which of the following nursing interventions demonstrate the nurse's understanding of the patient's ABG's and knowledge of Maslow's hierarchy of needs when providing care for this patient? The nurse prepares for endotracheal intubation and mechanical ventilation for the patient Lab values are within normal limits and contacts the patient's family to be with the patient while in the ED The nurse completes a spiritual assessment and provides appropriate clergy support for the patient The nurse immediately starts an intravenous line (IV) of dextrose 50% in a water solution (D50W)
The nurse prepares for endotracheal intubation and mechanical ventilation for the patient Explanation: This patient is experiencing respiratory alkalosis related to heatstroke. The pH level is elevated in hyperventilation; the patient's hyperventilation will "blow off" more CO2, leading to lower pCO2levels. Decreased pCO2 is caused by hyperventilation. Decreased CO2 levels are seen in renal failure. Renal failure is a sign of heatstroke. With rapid breathing SO2 can be increased with deep or rapid breathing. Acute airway management is indicated to improve tissue oxygenation. Airway support meets the patient's physiologic need for a clear airway. Spiritual support is a higher level (self-actualization) on Maslow's hierarchy. Providing IV management for circulatory support is a basic physiologic need; however, airway management is priority.
A client's most recent laboratory results suggest the presence of metabolic alkalosis. What action by the nurse best addresses a potential cause of this acid-base imbalance? Administering an antiemetic to treat the client's frequent vomiting Repositioning the client frequently to reduce pressure on dependent skin surfaces Assessing the client's bowel sounds and administering scheduled stool softeners Assessing the client's level of consciousness using the Glasgow Coma Scale
Administering an antiemetic to treat the client's frequent vomiting Explanation: Vomiting results in the loss of hydrogen ions, potentially resulting in metabolic alkalosis. Constipation and skin breakdown are not among the most common causes of metabolic alkalosis. Acid-base imbalances frequently affect cognition, but a change in level of consciousness would not be a cause of the imbalance.
Examination of a client's bladder stones reveal that they are primarily composed of uric acid. The nurse would expect to provide the client with which type of diet? Low oxalate Low purine High protein High sodium
Low purine Explanation: A low-purine diet is used for uric acid stones; the benefits, however, are unknown. Clients with a history of calcium oxalate stone formation need a diet that is adequate in calcium and low in oxalate. Only clients who have type II absorptive hypercalciuria—approximately half of the clients—need to limit calcium intake. Usually, clients are told to increase their fluid intake significantly, consume a moderate protein intake, and limit sodium. Avoiding excessive protein intake is associated with lower urinary oxalate and lower uric acid levels. Reducing sodium intake can lower urinary calcium levels.
A patient who has been treated for uric acid stones is being discharged from the hospital. What type of diet does the nurse discuss with the patient? Low-calcium diet High-protein diet Low-phosphorus diet Low-purine diet
Low-purine diet Explanation: For uric acid stones, the patient is placed on a low-purine diet to reduce the excretion of uric acid in the urine. Foods high in purine (shellfish, anchovies, asparagus, mushrooms, and organ meats) are avoided, and other proteins may be limited.
A client is admitted to the unit with diabetic ketoacidosis (DKA). Which insulin would the nurse expect to administer intravenously? Glargine Regular NPH Lente
Regular Explanation: Regular insulin is administered intravenously to treat DKA. It is added to an IV solution and infused continuously. Glargine, NPH, and Lente are only administered subcutaneously.
A client with a long history of alcohol abuse has been admitted to the emergency department after several of days of heavy drinking. The nurse can best promote the restoration of the client's acid-base balance by: encouraging pursed-lip breathing and deep breathing and coughing exercises. administering intravenous sodium bicarbonate as prescribed. administering intravenous magnesium sulfate as prescribed. positioning the client in an upright position when in bed and mobilizing the client frequently.
administering intravenous sodium bicarbonate as prescribed. Explanation: Sodium bicarbonate is among the more common treatments for the metabolic acidosis that results from high alcohol intake. Breathing exercises do not have appreciable effect, though respiratory compensation will likely be taking place. Magnesium sulfate addresses a likely electrolyte imbalance, not an acid-base imbalance. The client's position will have a negligible effect on acid-base balance.
Before weaning a client from a ventilator, which assessment parameter is the most important for the nurse to obtain? fluid intake for the past 24 hours baseline arterial blood gas (ABG) levels prior outcomes of weaning electrocardiogram (ECG) results
baseline arterial blood gas (ABG) levels Explanation: Before weaning the client from mechanical ventilation, it's most important to have baseline ABG levels. During the weaning process, ABG levels will be checked to assess how the client is tolerating the procedure. Other assessment parameters are less critical. Measuring fluid volume intake and output is always important when a client is being mechanically ventilated. Prior attempts at weaning and ECG results are documented on the client's record, and the nurse can refer to them before the weaning process begins.
