An adult presents with lightheadedness and shortness of breath; ABG shows alkalemia; most appropriate initial step?

• A. Have the patient breathe into a paper bag
• B. Administer IV diazepam
• C. Obtain cardiac enzymes
• D. Administer heparin

Answer: (A)

This scenario involves respiratory alkalosis from hyperventilation. When someone overbreathes, they blow off CO2 faster than it’s produced, lowering PaCO2 and raising pH, which causes lightheadedness and shortness of breath. The quickest fix is to increase CO2 levels again by rebreathing expired air, which raises PaCO2 and tempers the alkalemia. Having the patient breathe into a paper bag accomplishes this immediately and can alleviate symptoms.

Diazepam would depress respiration and worsen the alkalemia. Administering IV heparin or obtaining cardiac enzymes targets thromboembolic or cardiac etiologies and does not address the abnormal acid-base status of hyperventilation.