Final answer:
The postoperative patient with shallow respirations and continuous nasogastric tube suction likely has developed metabolic alkalosis, as the body attempts to compensate for the loss of hydrochloric acid by conserving CO2 through shallow respirations. The correct option is b.
Step-by-step explanation:
The nurse's observation of a postoperative patient with shallow respirations who has a nasogastric tube with continuous suction suggests that the patient may have developed metabolic alkalosis. Metabolic alkalosis can occur due to the loss of hydrochloric acid from the stomach, which often happens with continuous suctioning. Following the provided information on acid-base balances, such a condition can lead to an increase in blood pH and bicarbonate levels. However, the body's compensatory mechanisms are less efficient in returning the bicarbonate to carbonic acid ratio to the normal range in cases of metabolic alkalosis than they are for acidosis.
As the patient presents with shallow respirations, this is an indication of the body trying to conserve CO2 to increase the amount of carbonic acid and subsequently reduce the elevated pH back to normal. This is a normal respiratory compensation mechanism for metabolic alkalosis, yet efficiency in compensation is limited by the body's intolerance for decreased respiration.