Four hours after mechanical ventilation is initiated for a patient with chronic obstructive pulmo-nary disease (COPD), the patient’s arterial blood gas (ABG) results include a pH of 7.50, PaO2 of 80 mm Hg, PaCO2 of 29 mm Hg, and HCO3- of 23 mEq/. What change in ventilator settings would be indicated?


Selected Answer: Evidently, the patient is experiencing acute respiratory alkalosis that is uncompensated for. This is indicated by the low PaCO2 level that is below the normal range of 35-45 mmHg. The reduced PaCO2 value leads to increased blood alkalinity. To address this problem, compensate for it by reducing the amount of air the patient takes in per minute. To achieve this, decrease the respiratory rate reduce the breathing tidal volume. Also, if possible, facilitate excretion of body bicarbonate to compensate for the acute respiratory alkalosis. The essential respiratory setting is reduced respiratory rate and reducing the tidal volume. Correct Answer: The patient’s PaCO2 and pH indicate respiratory alkalosis. In mechanically ventilated patients who have respiratory alkalosis, the tidal volume and/or respiratory rate may need to be de-creased. Inadequate sedation and pain control may contribute to respiratory alkalosis in patients breathing over the set ventilator rate. The PaO2 is appropriate for a patient with COPD, Response Feedback: [None Given]