This man has overdosed (potentially on opioids due to the severe respiratory depression), which is causing him to hypoventilate (less breaths/minute and shallow breaths).

Hypoventilation leads to:

• Decreased O2 from decreased overall ventilation
• Increased CO2 because you are not expelling as much CO2 in breaths. He is also retaining more residual air with shallow breaths so there is more CO2.
• Acidosis from retained CO2
• Slightly increased bicarb (from normal of 24mEq/L) but not fully compensated because this is primarily a respiratory alkalosis and compensation thus takes time