BRTP08 Sampling, Analysis & Hemoximetry

Question 1

Primary purpose of taking arterial blood gases (ABG’s)

Answer 1

Determine adequacy of oxygenation and ventilation.

Question 2

Major hazards of ABGs

Answer 2

Bleeding
Obstruction of vessel
Infection

Question 3

Criteria for site selection

Answer 3

1. Collateral blood flow
2. Vessel accessibility
3. Peripheral structures
4. Hemodialysis fistula (fistula shunt)

Question 4

Preferred sites for ABGs

Answer 4

1. Radial artery
2. Brachial artery
3. Umbillical artery (commonly used in newborns)
4. Femoral artery

Question 5

What errors are shown in vitals when there is air in a sample?

Answer 5

Lower PaCO2
Raises pH
Raises low PaO2
Lowers high PaO2

(Will lower or raise PaO2 depending on O2 in blood)

Question 6

What error is showed in vitals when venous admixture occurs?

Answer 6

Raises PaCO2
Lowers pH
Can greatly lower PaO2

Question 7

What happens when there is excess anticoagulation?

Answer 7

Lowers PaCO2
Raises pH
Raises low PaO2
Lowers high PaO2

Question 8

Effect of metabolic effects?

Answer 8

Raised PaCO2
Lowers pH
Lowers PaO2

Sample must be put on ice for 30 mins

Question 9

What are the known pH values we will be using?

Answer 9

6.82 to 7.383

Question 10

Acceptable drift limits equal to two standard deviations for pH, PaCO2, PaO2?

Answer 10

pH (+/-) .04
PaCO2 (+/-) 3mmHg
PaO2 (+/-) 3mmHg

Question 11

How long does it take to reach steady state for normal lungs?

Answer 11

5-10 mins

Question 12

How long does it take to reach steady state for COPD?

Answer 12

20-30 mins

Question 13

How long should you wait to draw ABGs from a patient with COPD after making a change in oxygen percentage?

Answer 13

20-30 mins

Question 14

ABGs reflect lung function and?

Answer 14

1. Adequacy of oxygenation

2. Adequacy of ventilation

Question 15

What is the most sensitive indicator of oxygenation directly measured?

Answer 15

PaO2

Question 16

High PaCO2 is related to what?

Answer 16

Drowsiness

Question 17

What is the best way to evaluate the adequacy of ventilation?

Answer 17

PaCO2

Question 18

What are non respiratory values typically referred to as metabolic values?

Answer 18

HCO3
Base Excess (BE)

Question 19

Contraindications to ABG sampling?

Answer 19

Thrombolytic therapy (clot buster)
No collateral blood flow
Surgical arteriovenous shunt (dialysis shunt) (AV)
Lesions
Infection
Evidence of PVD aka peripheral vascualr disease

Question 20

Hazards of ABG Sampling

Answer 20

Bleeding and hemorrhage
Artery laceration (most serious)
Hematoma and bruising
Low platelet count (thrombocytopenia)
Anticoagulants
Obstruction of blood flow
Infection of the puncture site

Question 21

Other hazards of ABG sampling

Answer 21

Nerve damage 
Pain
Air or clotted blood
Vasovagal response (someone strains and passes out)
Self puncture

Question 22

What is the preferred site for an ABG and why?

Answer 22

Radial artery
Safest
Superficial (near surface)
Collateral circulation
Not near any large veins

Question 23

Second most common site if ABG and why?

Answer 23

Brachial artery

Requires additional training and riskier due to insufficient collateral circulation

Question 24

Riskiest ABG site?

Answer 24

Femoral artery

Typically Only performed by physicians

Additional training

Question 25

Alternate site or 3rd in line for ABG?

Answer 25

Dorsal pedis artery or pedal artery Has collateral flow Additional training

Question 26

What indicates a positive allens test?

Answer 26

After squeezing ulnar and radial artery, color (flushing) returns to hand

Question 27

What size needle is used for ABG in adults

Answer 27

22-25 gauge needle

Question 28

How do you assess for a puncture site?

Answer 28

Allens test Ensure no AV shunt

Question 29

What is a flash?

Answer 29

A spurt of blood

Question 30

If you see a flash but it stops prematurely what happened?

Answer 30

The needle went through the artery

Question 31

Air bubbles effect on PaCO2?

Answer 31

Air bubbles will ALWAYS decrease PaCO2

Question 32

What 3 things do blood gas analyzers measure?

Answer 32

pH PaCO2 PaO2

Question 33

Values calculated durint blood gas analyzation?

Answer 33

``` Hb saturation Plasma bicarbonate (HCO3) Base Excess (BE) ```

Question 34

What electrode measures pH?

Answer 34

Sanz Electrode

Question 35

What electrode measures PCO2?

Answer 35

Severinghaus or Stowe

Question 36

What electrode measures PO2?

Answer 36

Clark polarographic electrode

Question 37

“In vivo” meaning

Answer 37

Analzying INSIDE the artery

Question 38

“In vitro” meaning?

Answer 38

Removing blood then analyzing | Outside of body

Question 39

What is used for quality control?

Answer 39

Levey-jennings chart

Question 40

How do random errors occurs in levey jennings chart and how do you correct them?

Answer 40

Can just happen, or caused by sample contamination or mishandling Will be a singular error Recalibrate, rerun controls and samples

Question 41

How do systematic errors occur and how ste they corrected?

Answer 41

Can be caused by contaminated buffets, incorrect gas concentrations, component failure. To correct, check function, repair or replace failed components Will be a group of errors

Question 42

What are the two types of systematic errors?

Answer 42

Trend- gradual loss of reliability (subtle change) will look like a slope Shift- abrupt movement outside of acceptable range