ABG Study Questions and Answers with complete solution

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. - 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. - ANS: A The pH and HCO3 indicate that the patient has a metabolic acidosis. The ABGs are inconsistent with the other responses. 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 - ANS: AMorphine 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. 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 - 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 d) Metabolic alkalosis - ANS: B