Often patients experiencing sympathetically induced hyperventilation are told to breath in a paper bag. Why?

Question

Quizplus · Accepted Answer

The Answer is Hyperventilation results in the removal of excess CO₂, which causes the carbonic acid reaction to proceed to the left in an attempt to replace the CO₂ molecules lost to the atmosphere:
CO₂ + H₂O

\rightarrow

H₂CO₃

\rightarrow

H⁺ + HCO₃^-
According to the equation above, the more CO₂ that is lost, the more H⁺ are removed from the solution, and fewer are formed from the reaction of CO₂ and water. This causes the blood to become more basic; this phenomenon is called respiratory alkalosis. Breathing into a paper bag causes the exhaled CO₂ to re-enter the lungs and prevents the chemical reaction above from proceeding too rapidly to the left. The result is maintenance of sufficient numbers of H⁺ in the blood to prevent respiratory alkalosis.

Often Patients Experiencing Sympathetically Induced Hyperventilation Are Told to Breath