Final answer:
The next step in a mechanically ventilated patient with high pH, low pCO₂, and high pO₂ is to decrease the ventilator rate.
Step-by-step explanation:
In a mechanically ventilated patient with high pH, low pCO₂, and high pO₂, the next step would be to decrease ventilator rate (B).
When a patient has high pH, low pCO₂, and high pO₂, it indicates respiratory alkalosis. This means that the patient is hyperventilating and exhaling more carbon dioxide (CO₂) than normal, resulting in reduced levels of CO₂ in the blood and increased pH.
By decreasing ventilator rate, the patient's respiratory rate will also decrease, allowing them to retain more carbon dioxide and bring the pH back to a normal level.