Oxygen Transport Blood Buffers  Elmhurst College
Carbon Dioxide Transport Respiratory Acidosis Metabolic Acidosis  Chemistry Department
Buffers in the Kidenys Respiratory Alkalosis Metabolic Alkalosis  Virtual ChemBook

Hemoglobin - Oxygen Equation:

HHgb + O 2 <===> HgbO 2 + H+

Blood Buffer Equation:

CO2 + HOH <===> H2CO3 <===> H+ + HCO3-

Metabolic Alkalosis

Case 1: Use the following lab results to answer the following questions:
CO2 = 39; pCO2 = 40; pH = 7.6; K = 3.0. The patient has been vomiting.

a. List the condition - acidosis or alkalosis, metabolic or respiratory, compensated or uncompensated.


Use Table 2. pH = 7.6 and K = 3.0 both indicate an alkalosis condition. The pCO2 = 40 value is normal and therefore indicates a metabolic condition. The CO2= 39 value is measuring HCO3- and indicates an uncompensated condition.

Therefore, Metabolic Alkalosis - Uncompensated.

b. What is the primary cause of the condition?


Consult Table 2 and answer (a) above and consider the vomiting. This indicates a high pH and therefore deficit of H+.



c. Explain the other lab results using the primary cause and equilibrium principles.

Solution: Use the equilibrium:

CO2 + H2O === H2CO3 === H+ + HCO3-

pCO2 is normal. If pH is increased and H+ ions are decreased, the equilibrium shifts to the right and HCO3- is increased as indicated in the CO2 = 39 value.

d. State and explain how the compensation will return pH to normal using equilibrium principles.


Table 2 indicates that the lungs retain CO2. If CO2 is increased, the equilibrium in (c) will shift right and H2CO3- and H+ ions will increase, therefore the pH will decrease.

f. Explain how the treatment with NH4Cl will work?


NH4Cl is a salt of a weak base, therefore, its solution is acidic, therefore an increase of H+ ions will correct a H+ deficit and decrease the pH.

NH4Cl + HOH <===> NH4OH + H+ + Cl
weak base strong acid