A patient who has required prolonged mechanical ventilation has
the following arterial blood gas results: pH 7.48, PaO2 85 mm Hg,
PaCO2 32 mm Hg, and HCO3 25 mEq/L. The nurse interprets these
results as
a. metabolic acidosis.
b. metabolic alkalosis.
c. respiratory acidosis.
d. respiratory alkalosis. -
correct answer ✅ANS: D
The pH indicates that the patient has alkalosis and the low PaCO2
indicates a respiratory cause. The other responses are incorrect
based on the pH and the normal HCO3.
A patient has the following arterial blood gas (ABG) results: pH
7.32, PaO2 88 mm Hg, PaCO2 37 mm Hg, and HCO3 16 mEq/L. The
nurse interprets these results as
a. metabolic acidosis.
b. metabolic alkalosis.
c. respiratory acidosis.
d. respiratory alkalosis. -
correct answer ✅ANS: A
The pH and HCO3 indicate that the patient has a metabolic acidosis.
The ABGs are inconsistent with the other responses.
,ABG Study Exam Questions And Answers
A 2-year-old child was brought into the emergency department
after ingesting several morphine tablets
from a bottle in his mother's purse. The nurse knows that the child
is at greatest risk for which acid-base imbalance?
a) Respiratory acidosis
b) Respiratory alkalosis
c) Metabolic acidosis
d) Metabolic alkalosis -
correct answer ✅ANS: A
Morphine overdose can cause respiratory depression and
hypoventilation. Hypoventilation results in retention of CO2 and
respiratory acidosis. Respiratory alkalosis would result from
hyperventilation, causing a decrease in CO2 levels. Metabolic acid-
base imbalance would be a result of kidney dysfunction, vomiting,
diarrhea, or other conditions that affect metabolic acids.
A patient was admitted for a bowel obstruction and has had a
nasogastric tube set to low intermittent
suction for the past 3 days. The patient's respiratory rate has
decreased to 12 breaths per minute.
, ABG Study Exam Questions And Answers
The nurse would expect the patient to have which of the following
arterial blood gas values?
a) pH 7.78, PaCO2 40 mm Hg, HCO3- 30 mEq/L
b) pH 7.52, PaCO2 48 mm Hg, HCO3- 28 mEq/L
c) pH 7.35, PaCO2 35 mm Hg, HCO3- 26 mEq/L
d) pH 7.25, PaCO2 47 mm Hg, HCO3- 29 mEq/L -
correct answer ✅ANS: B
Compensated metabolic alkalosis should show alkalosis pH and
HCO3- (metabolic) values, with a slightly acidic CO2 (compensatory
respiratory acidosis). In this case, pH 7.52 is alkaline (normal = 7.35
to 7.45), PaCO2is acidic (normal 35 to 45 mm Hg), and HCO3- is
elevated (normal = 22 to 26 mEq/L). A result of pH 7.78, PaCO2 40
mm Hg, HCO3- 30 mEq/L is uncompensated metabolic alkalosis. pH
7.35, PaCO2 35 mm Hg, HCO3- 26 mEq/L is within normal limits. pH
7.25, PaCO2 47 mm Hg, HCO3- 29 mEq/L is compensated
respiratory acidosis.
The nurse would not expect full compensation to occur for which
acid-base imbalance?
a) Respiratory acidosis
b) Respiratory alkalosis
c) Metabolic acidosis