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Flashcards in ABGs Deck (41)
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1

An arterial blood gas is a test that measures _______, _________, ____________, and ____________.

Acidity (pH);
Oxygen Tension (PaO2);
Carbon Dioxide Tension (PaCO2);
Bicarbonate Concentration (HCO3)

2

Common sites to get arterial blood for an ABG

1. Radial
2. Brachial
3. Femoral (sometimes)

Rarely:
4. Dorsalis Pedis
5. Axillary Artery

3

T/F: It is important to draw blood from the radial or brachial arteries because the results of the ABGs will be more accurate to the rest of the body.

False, there is NO evidence that one site is better than another.

The radial artery is typically the easiest and most used access site.

4

This is the process used to collect radial arterial blood defined by the following process:

1. The patient’s hand is initially held upright with the fist closed and both the ulnar and radial arteries compressed (allowing blood to drain from the hand).
2. The hand is then lowered, fist opened, and pressure is released only from the ulnar artery.

Modified Allen Test

5

In the Modified Allen Test, the color should return to the hand within ________ after releasing the ulnar compression.

Six Seconds

6

What is the difference between the Allen Test and the Modified Allen Test?

Allen Test has you releasing the ulnar artery and then the radial artery on two different occassions testing the patency of both arteries.

7

What is the equation for the Bicarbonate-Carbon Dioxide Buffering System in the Blood?

Dissolved CO2 + H2O H2CO3 HCO3- + H+

8

How do you calculate the serum bicarb level/concentration?

Using the CO2 and pH measured by the ABG machine, you use the Henderson-Hasselbach Equation.

9

What is the Henderson Hasselbach equation?

pH = 6.1 + log( [HCO3-] / [0.03 x PCO2] )

10

Normal Range of pH

7.35 - 7.45

11

Normal Range of HCO3-

21 - 27 meq/L

12

Normal Range of PCO2

35 - 45 mmHg

13

Normal Range of PaO2

Varies because the treshold below which tissue hypoxiaoccurs is not an exact value and has not been defined.

14

This is the term for an arterial pH below the normal range ( < 7.35)

Acidemia

15

This is the term for a disorder that INCREASES the pH and REDUCES the PCO2

Respiratory Alkalosis

16

This is the term for an arterial pH above the normal range ( > 7.45)

Alkalemia

17

This is the term for a disorder that REDUCES the pH and REDUCES the HCO3-

Metabolic Acidosis

18

This is the term for a disorder that REDUCES the pH and INCREASES the PCO2

Respiratory Acidosis

19

This is the term for a disorder that INCREASES the pH and INCREASES the HCO3-

Metabolic Alkalosis

20

Step-Wise Approach for looking at ABGs:

1. Look at the pH
2. Determine the process that led to the acidemia or alkalemia. Look at the HCO3- and PCO2
3. Calculate the Anion Gap
4. Determine if a compensatory process is present
5. Determine if a Mixed Acid-Base Disorder is Present

21

If we see a patient with acidemia (pH < 7.35) and we see that the PCO2 is also elevated (>45), what is this condition?

Respiratory Acidosis

22

If we see a patient with alkalemia (pH > 7.45) and we see that the HCO3- is elevated (>27), what is this condition?

Metabolic Alkalosis

23

If we see a patient with acidemia (pH < 7.35) and we see that the HCO3- is low (< 21), what is this condition?

Metabolic Acidosis

24

If we see a patient with alkalemia (pH > 7.45) and we see that the PCO2 is low (<35), what is this condition?

Respiratory Alkalosis

25

How do you calculate the Anion Gap?

AG = Na+ - (Cl- + HCO3-)

26

What does an elevated Anion Gap (>12) imply?

Implies that the Patient has a Primary, Wide-Anion Gap Metabolic Acidosis

27

For primary respiratory acidosis (high PCO2), the compensatory process is ?

Metabolic Alkalosis
(Rise in serum HCO3-)

28

For primary respiratory alkalosis (low PCO2), the compensatory process is ?

Metabolic Acidosis
(Decrease in serum HCO3-)

29

For primary metabolic alkalosis (high HCO3-), the compensatory process is ?

Respiratory Acidosis
(High PCO2)

30

For primary metabolic acidosis (low HCO3-), the compensatory process is ?

Respiratory Alkalosis
(Low PCO2)