Acid Base Balance

Question 1

pH Normal Range

Answer 1

7.35-7.45

Question 2

CO2 Normal range

Answer 2

35-45 mmHg

Question 3

HCO3 Normal range

Answer 3

22-26 mEq/L

Question 4

SaO2 Normal range (SPO2)

Answer 4

> 95%

Question 5

PaO2 Normal range (pO2 or Partial Pressure of Oxygen)

Answer 5

80-100 mmHg

Question 6

Base (Deficit/Excess)

Answer 6

(-2) to (2+)

Question 7

Buffer system: Reacts in seconds

Answer 7

Bicarb (HCO3)/ Carbonic Acid (H2C03)

Question 8

Buffer system: Reacts in minutes

Answer 8

Lungs blow off/hold CO2

Question 9

Buffer system: React in hours to days

Answer 9

Kidneys resorb/excrete bicarb (HCO3)

Question 10

How does CO2 exist in the blood?

Answer 10

as a soluble gas

Question 11

What is a normal byproduct of metabolism?

Answer 11

CO2

Question 12

How is CO2 measured in solute?

Answer 12

Measured in partial pressure PaCO2

Question 13

What is the relationship between CO2 and respirations?

Answer 13

CO2 regulation is a function of MINUTE Volume and tidal volume (VT) X respiratory rate (F). If the PaCO2 is high respirations will increase; if PaCO2 is low, respiratory drive decreases; Apnea causes respiratory acidosis and eventually metabolic; Hyperventilation causes respiratory alkalosis and eventually metabolic alkolosis.

Question 14

Low HCO3

Answer 14

Low pH, >22 too little bicarb, too much H+

Question 15

High HCO3

Answer 15

High pH, <26 too much bicarb, too little H+

Question 16

What does a base deficit of >-4 indicate?

Answer 16

for the potential need for blood transfusion

Question 17

What does a base deficit of >-19 indicate?

Answer 17

Correlates with a poor outcome (death likely)

Question 18

Replacement formula of bicarb needed

Answer 18

0.1 x (-BE) x patient weight in kg x
i.e. pt weighs 110 kg and has a BE of -6.
Formula 0.1 x (-6) x 110 = 66 meq of bicarb needed

Question 19

PaO2 of 60 is roughly equal to what SaO2?

Answer 19

90%

Question 20

PaO2 and SaO2 correlation

Answer 20

40 mmhg / 50 mmHg / 60 mmHg = 70%/ 80%/ 90% SaO2

Question 21

What does 2,3 DPG do to the oxygen carrying abilities of Hgb?

Answer 21

2,3-DPG pries 02 off of hemoglobin

Question 22

What is the affinity for oxygen in a right shift?

Answer 22

decreased

Question 23

What is the affinity for oxygen in a left shift?

Answer 23

increased

Question 24

What happens in a left shift of the oxyhemoglobin dissociation curve?

Answer 24

Increased affinity of Oxygen to Hgb
decreased H+
decreased temp
decreased 2,3-DPG
low PCO2

Question 25

What happens in a right shift of the oxyhemoglobin dissociation curve?

Answer 25

Decreased affinity of Oxygen to Hgb
increased H+
increased temp
increased 2,3-DPG
High PCO2

Question 26

How does a change in CO2 of 10 mmHg affect pH?

Answer 26

pH changes 0.8 in opposite direction

Question 27

How does a change in CO2 of 10mmHg affect K+?

Answer 27

K+ changes 0.5 in the same direction

Question 28

How does a change in 0.1 of pH affect K+?

Answer 28

K+ changes 0.6 in the opposite direction

Question 29

How does a change in pH of 0.15 affect HCO3?

Answer 29

HCO3 changes 10 in the same

Question 30

Critical ABG’s for intubation

Answer 30

pH <7.2
pCO2 > 55
pO2 < 60

Question 31

Normal potassium range

Answer 31

3.5 - 5.0 mEq/L