Acid base balance

Question 1

PCO2

Answer 1

Partial pressure of CO2 gas dissolved in blood and useful for assessing alveolar ventilation

Question 2

PO2

Answer 2

Dissolved O2 not O2 bound to Hgb. Used to assess pulmonary gas exchange. Tells us blood oxygenation so only useful with arterial blood

Question 3

Electrochemical analyzers

Answer 3

Evaluates BG and electrolytes
-Measures H+, PO2, and PCO2
-HCO3 is calculated

Question 4

Sample handling for electrochemical analyzers

Answer 4

-Used heparinized whole blood sample
-Minimize contact with air (leads to decreased HCO3) and remove gas bubbles
-Immediate analysis is ideal

Question 5

Erroneous values

Answer 5

-Exposure to air
-Excess heparin
-Delayed sample analysis

Question 6

Acid

Answer 6

Liberates H ions in solution

Question 7

Base

Answer 7

Accept H ions and remove from solution

Question 8

1 unit increase in pH leads to

Answer 8

10 decrease in H+

Question 9

Plasma pH normal

Answer 9

7.38-7.44

Question 10

Volatile acid (CO2 ) generation

Answer 10

-Carbohydrate oxidation
-B-oxidation of fatty acids

Question 11

Non-volatile acid (H+) generation

Answer 11

-Carbohydrate oxidation (Lactic acid)
-B-oxidation of fatty acids (ketone bodies)
-Amino acid oxidation
-Nucleic acid oxidation

Question 12

Control of H

Answer 12

-Chemical (bicarb is the most important)
-Pulmonary (CO2 eliminated in lungs)
-Hepatic (ammonium into urea and glutamine formation)
-Renal (H eliminated in urine)

Question 13

CO2 as an acid

Answer 13

Not an acid on its own, but when dissolved in water it forms carbonic acid. Excreted by the lungs

Question 14

Normal ratio of HCO3 to CO2

Answer 14

20:1