Biomedical [Basics] what is Blood Gas analysis?

Blood Gas analysis (part 2)

Po2 electrode

History

Leland Clark (Professor of Chemistry, Antioch College, Yellow Springs, Ohio, and Fels Research Institute, Yellow Springs, Ohio) had developed the first bubble oxygenator for use in cardiac surgery. However, when he came to publish his results, his article was refused by the editor since the oxygen tension in the blood coming out from the device could not be measured. This instigated Clark to develop the oxygen electrode

Principle

• Based on Redox reaction
• Cathode (Pt) is reduced
• Anode (Ag/Agcl) is oxidised
• The resulting current linearly proportional to oxygen concentration
• Operating voltage 0.68V (Since in V I characteristics of Po2 electrode around 0.6 to 0.7V current is constant)

Construction

Membrane - Polystyrene

Complete Blood Gas Analyzer

Separate amplifier for each electrode output
Sample size : 25uL
Response time: 1 - 5 mins

Accurate measurement of following parameters
a) pH
b) pCO2
c) pO2
d) Haematocrit and Hemoglobin
e) Electrolytes Sodium,Potassium andChloride Ca++ and Magnesium
f) Lactate
g)The equipment should possess electrodes with long life at least 2 years

Electrodes placed in temperature controlled chamber