Question

A nurse cares for a patient who has a nasogastric tube attached to low suction because of a suspected bowel obstruction. Which of the following arterial blood gas results might be expected in this patient?

1) pH 7.52, PCO₂54 mm Hg.
2) pH 7.42, PCO₂40 mm Hg.
3) pH 7.25, PCO₂25 mm Hg.
4) pH 7.38, PCO₂36 mm Hg.

Answer 1

Option 1) pH 7.52, PCO₂ 54 mm Hg may indicate a metabolic alkalosis with respiratory compensation in a patient with a nasogastric tube suction due to excessive loss of stomach acid. However, without bicarbonate values, the full diagnosis is incomplete. The correct option is 1.

Step-by-step explanation:

The question concerns the expected arterial blood gas results in a patient with a nasogastric tube attached to low suction because of a suspected bowel obstruction.

Referring to reference values, normal arterial pH is between 7.35 and 7.45 and normal PCO₂ for males is 35-48 mm Hg and for females is 32-45 mm Hg. Given the situation of low suction via a nasogastric tube, there's potential for excessive loss of stomach content, which could lead to a metabolic alkalosis condition due to loss of gastric acid.

In metabolic alkalosis, the pH would be expected to be elevated. Among the provided options, only option 1) pH 7.52, PCO₂ 54 mm Hg shows an elevated pH.

However, the PCO₂ is high, indicating a respiratory component possibly due to compensation. Without additional bicarbonate values, the complete picture is not clear. Still, based on pH alone, a metabolic alkalosis is most likely. The correct option is 1.