ABG

Question 1

ABG contraindications?

Answer 1

1. Inadequate collateral circulation at puncture site
2. Should not be performed through lesion or surgical shunt
3. Evidence of PVD distal to puncture site
4. Coagulopathy or med-high dose anti-coagulation therapy.

Question 2

What is a modified Allen test?

Answer 2

Determines adequate collateral circulation.

Patient clenches fist then occlude both arteries.
Allow patient to unclench fist.
Release ulnar artery - if colour returns within 10s indicates adequate circulation.

Question 3

What are the H+ parameters on ABG?

Answer 3

35 - 45 nmol/L

45 = acidaemia

Question 4

What are the pH parameters on ABG?

Answer 4

pH: 7.35 - 7.45

7.45 = alkalaemia

Question 5

What are the PO2 parameters in ABG?

Answer 5

pO2 >80mmHg

Drive for O2 molecules to move onto Hb.

Question 6

What are the pCO2 parameters on ABG?

Answer 6

pCO2: 35 - 45 mmHg

Directly related to CO2 concentration in blood.

Question 7

what are the SO2 parameters on ABG?

Answer 7

> 96% RA.

Question 8

What are the HCO3act parameters on ABG?

Answer 8

22-28 mmol/L
High = metabolic alkalosis
Low = metabolic acidosis

Question 9

What is standard bicarbonate? What are its parameters on ABG?

Answer 9

Plasma bicarbonate concentration calculated from the PCO2 and pH measurements in arterial blood AFTER pCO2 in sample corrected to 40mmHg.
22-28 mmol/L

Question 10

What is Base excess?

Answer 10

Calculation of the amount of base that needs to be added to or removed from a sample to achieve neutral pH at 37C, after pCO2 has been corrected to 40mmHg.

Question 11

What does a positive base excess indicate?

Answer 11

More base than normal: metabolic alkalosis

Question 12

What does a negative base excess indicate?

Answer 12

Less base than normal: metabolic acidosis

Question 13

Plasma sodium?

Answer 13

135 - 145 mmol/L

Question 14

Plasma potassium?

Answer 14

3.5 - 5 mmol/L

Question 15

Cl plasma?

Answer 15

95 - 105 mmol/L