Ch. 12 Acid Base Balance and Imbalance

The nurse obtains lab results for a 50-year-old patient with the following results: pH 7.24; bicarbonate 20; Pao2 82; Paco2 35. These findings are consistent with which acid-base imbalance?

Metabolic acidosis: In metabolic acidosis , there is a decrease in pH (normal is 7.35-7.45), a decrease in bicarbonate (normal is 21-28), a normal Pao2 (normal is 80-100), and a normal or decreased Paco2 (normal is 35-45).

What is one of the causes of acidosis?

Kidney failure: Causes of acidosis include kidney failure, pancreatitis, liver failure, and dehydration. Excessive body fluids, heart failure, and colitis are causes of alkalosis.

A 60-year-old patient is admitted to the hospital with symptoms of a disturbance in acid-base balance. Which pH value would be consistent with an excessive amount of acids in the body?

7.26

A patient is admitted with chronic anemia. What physiologic imbalance does the nurse suspect the patient is at risk of developing?

Acidosis

A patient admitted to the emergency department is having an acute episode of asthmatic bronchitis. The nurse notes the pH on the most recent arterial blood gas is 7.31. What is the most likely explanation for this finding?

Acidosis in response to the excessive retention of carbon dioxide Patients who have asthmatic bronchitis and resulting impaired respiratory function retain carbon dioxide, which leads to acidosis. This patient is not retaining bicarbonate. An increase of hydrogen ions would occur with acidosis.

What is one of the causes of respiratory alkalosis?

Anxiety: Hyperventilation is one cause of respiratory alkalosis, which can result from fear and anxiety. Kidney failure and diuretic therapy are not causes of respiratory alkalosis. The use of antacids can result in metabolic alkalosis.

When caring for a patient with a pulse oximetry level of 89%, which action does the nurse take first?

Apply oxygen as prescribed- Applying oxygen is the first priority for a patient with hypoxemia. It is unclear whether the patient is stable to be out of bed; elevating the HOB (head of bed) would be more appropriate to improve respiratory expansion. Notifying the health care provider is an appropriate action after initiation of oxygen therapy; delaying intervention while waiting for the provider delays treatment. Breath sounds can be auscultated after initiation of oxygen therapy; hypoxemia may be present in the absence of adventitious breath sounds.

The nurse is caring for a patient with hypoxemia and metabolic acidosis. Which task can be delegated to the nursing assistant who is helping with the patient's care?

Apply the pulse oximeter for continuous readings.

The nurse is caring for a group of patients with acidosis. The nurse recognizes that Kussmaul respirations are consistent with which situation?

Aspirin overdose

The nurse is assessing the laboratory reports of a patient with impaired kidney function. What changes indicate the patient has metabolic acidosis?

Decrease in serum bicarbonate level

Which action does the nurse take first for the patient who is admitted to the emergency department (ED) with a panic attack and whose blood gases indicate respiratory alkalosis?

Encourage the patient to take slow breaths: Because respiratory alkalosis is caused by hyperventilation, the nurse's first action should be to assist the patient in slowing the respiratory rate. Respiratory alkalosis is caused by hyperventilation; fluid and electrolyte replacement will not help correct hyperventilation. No evidence suggests that hypoxemia exists; therefore, oxygen is not needed at this time. Ongoing respiratory alkalosis may eventually cause fluid and electrolyte shifts requiring IV emergency drugs; however, slowing the breathing and rebreathing of CO2 are the priority interventions.

A new nurse graduate is caring for a postoperative patient with the following arterial blood gases (ABGs): pH 7.30; Paco2 60 mm Hg; Pao2 80 mm Hg; bicarbonate 24 mEq/L; and O2 saturation 96%. Which of these actions by the new graduate is indicated?

Encourage the patient to use the incentive spirometer and cough

A patient is admitted with severe diabetic ketoacidosis. Arterial blood gas results reveal a pH of 7.21. What is this patient's acidosis most likely in response to?

Excessive breakdown of fatty acids: Metabolic acidosis can result from the overproduction of hydrogen ions, underelimination of hydrogen ions, or insufficient bicarbonate ions. Excessive breakdown of fatty acids that occurs with diabetic ketoacidosis or starvation results in overproduction of hydrogen ions and metabolic acidosis. Anaerobic metabolism produces lactic acid as a cause of metabolic acidosis. Excessive intake of alcoholic beverages will also cause metabolic acidosis because of the high concentration of hydrogen ions in alcohol. Excessive intake of insulin will not result in diabetic ketoacidosis.

When caring for a patient with metabolic acidosis, what must the nurse keep in mind regarding acid-base chemistry?

Fluids with lower pH have higher acidity.- Fluids with lower pH have a higher level of free hydrogen ions and, therefore, have higher acidity. Acids release hydrogen ions rather than bind with them when dissolved in water. Strong acids readily dissociate in water and release all of their hydrogen ions. Acetic acid (CH3COOH) is a weak acid. When dissolved in water, it releases only one of its four hydrogen molecules. Normally, blood has a pH of between 7.35 and 7.45, so it is slightly alkaline.

The nurse is caring for a patient who has taken a large quantity of furosemide to promote weight loss. The nurse anticipates the finding of which acid-base imbalance?

HCO3- of 34 mEq/L

A patient is admitted from the emergency department for intravenous (IV) fluids to treat dehydration caused by several days of vomiting and diarrhea. The patient's admission venous blood work reveals a pH of 7.27 and bicarbonate of 26 mEq/L; potassium and chloride levels are within normal ranges. The provider has ordered adding bicarbonate to the IV fluids. Which action by the nurse is correct?

Hold the bicarbonate and report the laboratory values to the provider.

Which electrolyte imbalance is the patient with metabolic acidosis at risk to develop?

Hyperkalemia

Which nursing intervention takes priority for a patient admitted with severe metabolic acidosis?

Initiate cardiac monitoring. The nurse follows the ABCs and initiates cardiac monitoring to observe for signs of hyperkalemia or cardiac arrest. Medication reconciliation should be performed as soon as possible; however, this patient is at risk for cardiac and neurologic complications of acidosis. Starvation may precipitate ketosis/acidosis, but this is not the priority.

A morbidly obese patient has chosen gastric bypass surgery to promote weight loss. The nurse plans to teach the patient about the need to perform monitoring to detect what disturbance consistent with rapid weight loss associated with this procedure?

Ketosis- Starvation, fasting, or following a strict calorie-reduced diet with rapid weight loss contributes to ketone formation and metabolic acidosis. Weight loss should decrease the work of breathing and improve hypoxemia, if present, as well as hypoventilation. Urinary retention does not occur in acid-base imbalance.

To decrease the risk of acid-base imbalance, what goal must the patient with diabetes mellitus strive for?

Maintaining blood glucose level within normal limits.

A patient has been having acute diarrhea for more than 24 hours from a viral infection. Which acid-base imbalance is most likely to manifest?

Metabolic acidosis

When evaluating the laboratory results of a patient with diabetic ketoacidosis, which lab value indicates the body has fully compensated from this acid-base imbalance?

Normal pH on arterial blood gases- Arterial blood gas pH returns to normal when the body's compensatory efforts are fully effective. Glucose, potassium, and bicarbonate are affected by diabetic acidosis, but their return to normal is not an indicator of acid-base balance.

A diabetic patient shows symptoms of diabetic ketoacidosis. What mechanism causes acidosis in this patient?

Overproduction of hydrogen ions- In diabetic ketoacidosis, there is an excessive breakdown of fatty acids. This produces strong acids (ketoacids) with the release of large amounts of hydrogen ions. Underelimination of hydrogen ions occurs when hydrogen ions are produced at normal rates, but their elimination is reduced. This is seen in patients with lung and kidney problems. Bicarbonate ion is made in the kidney or in the pancreas. In patients with impaired kidney or pancreatic function, there is underproduction of bicarbonate ions leading to acidosis. Overelimination of bicarbonate ions occurs when there is an excessive loss of bicarbonate ions. This occurs in diarrhea.

When caring for a patient with kidney failure who has metabolic acidosis, which symptom does the nurse expect as evidence of the body's compensatory effort?

Rapid and deep respirations:Kussmaul respirations (rapid, deep respirations) represent the body's attempt to compensate for metabolic acidosis. The skin is warm, dry, and flushed in metabolic acidosis. Cardiovascular symptoms may occur, but they are manifestations of acidosis, not evidence of compensation.

A lab report for a 47-year-old patient shows the following results: pH 7.32; bicarbonate 24; Pao2 77; Paco2 48. These findings are consistent with which acid-base imbalance?

Respiratory acidosis: In respiratory acidosis, there is a decrease in pH (normal is 7.35-7.45), a normal bicarbonate (normal is 21-28), a decreased Pao2 (normal is 80-100), and an increased Paco2 (normal is 35-45).

A patient with diabetes mellitus is brought to the emergency department after vomiting for several days. The patient has rapid, deep respirations and a urine dipstick reveals ketonuria. Which process does the nurse suspect is occurring with this patient?

Respiratory compensation for metabolic acidosis

Which arterial blood gas reading does the nurse anticipate in a patient diagnosed with chronic obstructive pulmonary disease (COPD)?

pH 7.36, Pao2 63 mm Hg, Paco2 52 mm Hg, HCO3- 32 mEq/L