Acid-Base

Question 1

What lactate value indicates shock?

Answer 1

Anything greater than 2 mol/L

Question 2

PaCO2 Change Formula (Effect on pH)

Answer 2

A PaCO2 change of 10mmHg will cause a pH change of .08 in the OPPOSITE direction

ex. A 10mmHg DROP in PaCO2 from 40 to 30 in a person with a pH of 7.4 will cause the pH to rise to 7.48.

Question 3

What are the primary buffering systems

Answer 3

1) Carbonic Acid
2) Respiratory
3) Renal

Question 4

What are the secondary buffering systems?

Answer 4

1) Protein buffering system
2) Phosphate buffering system (Comes form the bones)

Question 5

pH Change Formula (Effect on K+)

Answer 5

For every change in pH of 0.1 we see a change in K+ of 0.6 in the OPPOSITE direction

Question 6

PaCO2 Change Formula (Effect on K+)

Answer 6

A PaCO2 change of 10mmHg will cause a K+ change of .5 in the SAME direction

Question 7

What is the first line Tx for a critical hyperkyaemic patient

Answer 7

Calcium Chloride (CaCl)
Bicarb (NaHCO3)
D50/Insulin
Beta-2 Agonist

Question 8

How much mEqs of supplemental potassium is required to raise serum potassium by 1mEq/L

Answer 8

100-200

Question 9

What is the max rate for IV K+?

Answer 9

0.5-1.0 mEq/kg/hr

You should not administer greater than 10-20mEq/hr

Question 10

What is normal pH range?

Answer 10

7.35-7.45

Question 11

What is normal PaCO2 range?

Answer 11

35-45

Question 12

What is normal HCO3 range?

Answer 12

22-26

Question 13

What is normal PaO2 range?

Answer 13

80-100

Question 14

What is normal BE (Base Effect)?

Answer 14

-2 to 2

Question 15

What is Methomoglobinemia?

Answer 15

Methly groups attach to hemoglobin instead of O2. This usually results in an O2 sensor to consistently read at 85% due to change in color of the hemoglobin. Is caused by:
Nitrates
Sulfonamides
Pesticides
Herbicides
Topical benzocaine / lidocaine
Auto exhaust fumes
Nitrobenzine (oil products)

Question 16

What is Tx for Methomoglobinemia?

Answer 16

O2 then Methylene Blue

Question 17

What are the normal lab values for an ABG?

Answer 17

1) Ph 7.35-7.45
2) PaCO2 34-45
3) HCO3 22-26
4) PaO2 80-100
5) SaO2 >95%
5) BE -2 - 2

Question 18

What should you consider increasing in a patient with respiratory acidosis on vent management?

Answer 18

Increase tidal volume to overcome dead space until plateau pressure “bump up”.

Question 19

Formula for configuring ideal Vt?

Answer 19

Vt = 6-10ml/kg for ideal body weigh

Question 20

What does an anion gap >20 indicate?

Answer 20

Metabolic acidosis

Question 21

Top causes of metabolic acidosis

Answer 21

1) Shock
2) DKA
3) Renal Failure

Then consider EtoH, heavy metal poisoning, toxins

Question 22

M.U.D.P.I.L.E.S.

Answer 22

Causes of metabolic acidosis

Question 23

Bicarb Gap Formula

Answer 23

Na-Cl - 39 = Bicarb Gap
Gap > 6 = Metabolic Alkalosis (Bicarb retention)
Gap < -6 = Metabolic Hyperchloremic Acidosis (Stop NS)