QUES. 8: Case 4:
Uncompensated Laboratory Results: pH =7.2, pCO2 = 60, CO2
a. List the condition - acidosis or alkalosis, metabolic or
respiratory, compensated or uncompensated.
pH = 7.2 indicates acidosis, uncompensated
pCO2 = 60 = respiratory
CO2 = 24 = respiratory, uncompensated
b. What is the primary cause of the condition?
Respiratory acidosis is caused when carbon dioxide is not
removed from the blood due to hypoventilation, (slow breathing)
or obstructions in the exchange of gases. Such conditions are
caused by emphysema, asthma, bronchitis, pneumonia and pulmonary
edema. Carbon dioxide increases in the blood since it cannot
effectively diffuse out of the lungs.
c. Explain the other lab results using the primary cause and
Equilibrium: CO2 + HOH === H2CO3 === H+ + HCO3-
Compare the lab results with the normal values. In respiratory
acidosis, the increased carbon dioxide is the primary cause for
the other lab results. Increased CO2 causes the equilibrium
to shift right increasing H2CO3, H+
and HCO3-. Increased H+ ion
leads to decreased pH, (7.l5) from normal 7.4. The HCO3-
(30 mmoles) is slightly higher than normal.
d. State and explain how the compensation will return pH to
normal using equilibrium principles. Look at the table 2 to find
The body has its own methods to correct abnormalities in pH.
These are referred to as "compensation" methods. If
one remembers that there are two main acid-base regulatory mechanisms,
then in a case of respiratory acidosis, the kidneys attempt to
compensate for the low pH.
The compensation is to increase excretion of H+
ion and therefore increase the retention or reabsorption of HCO3-
into the blood. An increase in HCO3- ions
in the blood causes the buffer equation to shift left, thus H+
ions decrease and pH increases.
Typical compensated lab results are: pH = 7.35, HCO$b3$s$s-$b
= 35, pCO$b2$s = 70. Note that the pH is normal, but other lab
results are abnormal.
e. Explain how the treatment with __?___ will work using equilibrium
The best solution to improve respiratory acidosis is to treat
the cause for hypoventilation. This would decrease the pCO2,
decrease H+ and increase pH.
An emergency treatment would be to administer NaHCO3-.
This would have the effect of shifting the blood buffer equilibrium
to the left to decrease hydrogen ions and increase the pH back