Blood Gas Analysis

Question 1

Define a preanalytical error

Answer 1

When an error happens before the blood sample has been introduced to to the analyzer

Question 2

What is the acronym for pre-analytical errors

Answer 2

AVERT

Question 3

What does the AVERT acronym stand for?

Answer 3

A=Air in the sample
V=Venous Sample or venous admixture
E=Excessive or improper anticoagulant
R=Rate of metabolism
T=Temperature disparities between patient and analyzer

Question 4

What effect will air in the syringe have on PO2

Answer 4

Can increase or decrease

Question 5

What effect will air in the syringe have on PCO2

Answer 5

Decrease

Question 6

What effect will air in the syringe have on pH

Answer 6

Increase

Question 7

What effect does venous blood have on PO2?

Answer 7

Decreases

Question 8

What effect does venous blood have on PCO2?

Answer 8

Increases

Question 9

What effect does venous blood have on pH?

Answer 9

Decreases

Question 10

What effect does excessive anticoagulant have on PO2?

Answer 10

increases

Question 11

What effect does excessive anticoagulant on PCO2?

Answer 11

None

Question 12

What effect does excessive anticoagulant on pH?

Answer 12

Decreases it

Question 13

What effect does rate of metabolism have on PO2?

Answer 13

Decrease

Question 14

What effect does increased metabolism have on PCO2?

Answer 14

Increase

Question 15

What effect does rate of metabolism have on pH?

Answer 15

decrease

Question 16

What does the R in AVERT also refer to beside metabolic rate?

Answer 16

Delay in analysis and/or more than 30 minutes without ice

Question 17

What can PaCO2 tell us regarding CO2 excretion?

Answer 17

Provides direct information regarding lung function in terms of the adequacy of CO2 excretion

Question 18

What can cause an increase in PvO2?

Answer 18

Can indicate an increase in the rate of local metabolism or a decrease in local perfusion

Question 19

T/F: Levels of PvO2 can vary greatly in different areas of the body and provide limited information regarding pulmonary function

Answer 19

True

Question 20

In what conditions does venous pH correlate well with arterial pH?

Answer 20

Patients with uremic acidosis and diabetic keto acidosis

Question 21

If you are given a venous pH, what is the formula to determine the arterial pH?

Answer 21

Arterial pH = venous pH x 1.004

Question 22

If you have a venous blood gas and need to determine the arterial CO2 levels, what is the formula you would use?

Answer 22

Arterial PaCO2 = Venous PaCO2 x 0.873

Question 23

What are examples of analytical errors?

Answer 23

1. Improper equipment handling
2. Control testing not performed
3. Equipment malfunction
4. Not allowing proper cooking time (electrodes in the equipment need to respond to a stabilized sample)

Question 24

What are examples of post/non-analytical errors?

Answer 24

Transcription issue
Improper documentation

Question 25

What disease processes can cause erroneous blood gas results?

Answer 25

Carboxyhemoglobinemia Methemaglobinemia

Question 26

What red flags should make you either doubt or re-do the ABG?

Answer 26

1. Inconsistent with patient behavior 2. Extreme values 3. Significant changes without explanation 4. Internally inconsistent results

Question 27

How often should quality control tests and calibration procedures be performed on ABG analyzers?

Answer 27

Every 8 hours

Question 28

How often are therapists required to complete competencies in regards to drawing, handling and analyzing blood gas samples?

Answer 28

Annually

Question 29

How long should ABG results be available in the patients chart?

Answer 29

For at least 2 years

Question 30

An ABG analyzer is considered to be functioning properly if it is within how many standard deviations?

Answer 30

+/-2 standard deviations

Question 31

What is point of care testing?

Answer 31

Testing done at the bedside

Question 32

What tests are common performed at the bedside? (POC)

Answer 32

Blood gases, serum electrolytes, glucose, Hct