Look at Mrs. Hoffman's arterial blood gas values from the day she was admitted

Question

What will be an ideal response?

Answer 1

a. Why would arterial blood gases (ABGs) be drawn for this patient?

• Arterial blood gases are measured to evaluate the level of oxygen in the blood, the adequacy of ventilation, and acid-base balance.
• Arterial blood is sampled because it better measures a mixture of blood throughout the body as compared to venous blood (due to the tissue uptake of O2 and CO2 release).

b. Define each of the following and interpret Mrs. Hoffman's values:

pH
• Overall pH of the blood.
• Normal is 7.35-7.45
• Mrs. B's is 7.29, which means she is experiencing acidosis.
pCO2
• Measures the level of carbon dioxide in the blood.
• Because of the relationship of CO2 to carbonic acid, CO2 is used as an indirect measure of acidity in the body.
• Mrs. B has an elevated level, which is consistent with respiratory acidosis.
SO2
• Measures oxygen saturation of the blood.
• Mrs. Hoffman's is low and is consistent with her diagnosis.
HCO3-
• Measures bicarbonate ions, a base, in the blood.
• One of the major components of the buffer system.
• Initially, the kidney will attempt to compensate for the acidosis by retaining bicarbonate ions.
• At this point, HCO3- levels may be elevated.
• When the acidosis continues, the body is unable to keep up and the level of bicarbonate returns to normal.
• This is the situation with Mrs. Hoffman.

c. Mrs. Hoffman was placed on oxygen therapy. What lab values tell you the therapy is working?

pH, CO2, and O2 all returned to normal.