Respiratory Acidosis

How do you fix respiratory acidosis?

 Respiratory acidosis may not be fixable but pH can be compensated by renal retention of bicarbonate (HCO3-) to return pH to the normal range of 7.35 - 7.45. Normal values of PCO2 and HCO3- are 40 mm Hg and 24 mEq/L respectively. The equation to calculate pH (Henderson-Hasselbalch equation) using these values is:

pH = 6.1 + log ([HCO3-]/PCO2 x 0.03)

or

pH = 6.1 + log ([24]/ 40x 0.03)

or

7.4 = 6.1 + log 20

or

7.4 = 6.1 + 1.3

In severe respiratory acidosis (e.g., chronic emphysema), PCO2 may increase to 80 mm Hg.

In this case, an acute change of PCO2 from 40 to 80 mmHg results in:

pH = 6.1 + log ([28]/ 80 x 0.03)

or

pH = 6.1 + log 11.66

or

pH = 6.1 + 1.06 = 7.16

With a chronic change (obstructive lung disease), HCO3- is increased by kidneys

pH = 6.1 + log ([48/ 80x 0.03)

or

7.4 = 6.1 + log 20

or

7.4 = 6.1 + 1.3