Equipment

Question 1

What does the Polarogrpahic (Clark) Electrode measure?

Answer 1

Oxygen partial pressure

Question 2

What is the cathode and anode made of in the Clark electrode?

Answer 2

Cathode: platinum
Anode: Silver / Silver Chloride

Question 3

What reactions occur in the Polarographic electrode?

Answer 3

Cathode: 02 + 2H20 + 4e- = 4OH-

Anode: Ag + Cl- = AgCl + e-

Question 4

What are the measuring electrode and Calomel reference electrode made of in the pH electrode?

Answer 4

Calmol Reference Electrode: Mercury

Measuring Electrode: Silver/Silver Chloride

Question 5

How does a pH electrode work?

Answer 5

Two electrodes crease an electrical circuit, allowing a potential to be measured

Reference electrode maintains constant potential (KCL solution in contact with mercury electrode) - in contact with blood sample via membrane and cotton plug

Measuring electrode maintains pH within glass blub due to buffer solution; but an electrical potential exists due to a pH gradient

Question 6

What does a Severinghaus electrode measure?

Answer 6

CO2 (Indirectly)

pH directly via a reaction with CO2 and water ion the electrolyte solution

Question 7

What is the chemical equation of the reaction that occurs in a Severinghaus electrode?

Answer 7

CO2 + H20 > H+ + HCO3-

Question 8

What are the electrodes made from in a Severinghaus electrode?

Answer 8

Reference Electrode: Ag / AgCl

Measuring pH Sensitive Glass Electrode

Question 9

What are the 5 NAPSE codes for pacemakers?

Answer 9

Position I: chamber(s) paced
Position II: chamber(s) sensed
Position III: mode of response
Position IV: programmable functions
Position V: multi-site pacing

Question 10

What are the options available for position III, IV and V according to the NAPSE pacemaker codes?

Answer 10

Position III: mode of response – T (triggered), I (inhibited), D (triggered or inhibited), O (none)

Position IV: programmable functions – R (rate modulated), O (none)

Position V: multi-site pacing – O (none), A (atria), V (ventricles), D (dual)

Question 11

What settings are possible for the paced and sensed modes, according to the NAPSE codes?

Answer 11

Position I: chamber(s) paced – V (ventricle), A (atrium), D (ventricle and atrium), O (none).

Position II: chamber(s) sensed – V (ventricle), A (atrium), D (ventricle and atrium), O (none)

D = DUAL