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
