FPC: acid base made easy

Question 1

You look at a patient’s pH and they have a low pH with low bicarb. What is this?

Answer 1

Metabolic acidosis

Question 2

You look at a patient’s pH and they have a low pH with high pCO2. What is this?

Answer 2

Respiratory acidosis

Question 3

You look at a patient’s pH and they have a high pH with high bicarb. What is this?

Answer 3

Metabolic alkalosis

Question 4

You look at a patient’s pH and they have high pH with low pCO2. What is this?

Answer 4

Respiratory alkalosis

Question 5

What is normal pH?

Answer 5

7.35-7.45

Question 6

A pH less than ___ is incompatible with life.

Answer 6

6.8

Question 7

A pH greater than ___ is incompatible with life.

Answer 7

8.0

Question 8

What acid does aerobic metabolism produce?

Answer 8

Carbonic acid

Question 9

What acid does anaerobic metabolism produce?

Answer 9

Lactic, phosphoric, sulfuric acids

Question 10

What is a buffer pair?

Answer 10

Combination of acid and base that prevents pH changes. This is a strong base and weak acid.

Question 11

How can we use pCO2 to find carbonic acid?

Answer 11

pCO2 x 0.03

Question 12

What is the Henderson-Hasselbach equation?

Question 13

What is a simple formula for pH?

Answer 13

(HCO3-)/pCO2

Question 14

How can we measure acid-base from arterial blood?

Answer 14

pH, pCO2, calculated bicarb

Question 15

How can we measure acid-base from venous blood?

Answer 15

Bicarb, Na+, K+, Cl-

Question 16

How do the lungs contribute to acid-base balance?

Answer 16

Removes acid via exhalation of carbonic acid as H2O and CO2.

Question 17

How do the kidneys contribute to acid-base balance?

Answer 17

Removes acid via excreting acid phosphate and ammonium ion and reabsorption of Na+ and bicarb in exchange for a proton.

Question 18

In what case do we see Kussmaul breathing? Why?

Answer 18

In metabolic acidosis; there is decreased bicarb that causes decreased pH. We can compensate via these rapid deep breaths that blow off CO2 to prevent pH from dropping too much.

Question 19

How do we measure unmeasured anions?

Answer 19

Anion gap

Question 20

What can give you metabolic acidosis with normal anion gap?

Answer 20

Diarrhea, renal tubular acidosis, hyperalimentation, early renal failure.

Question 21

What are some acid loss causes of metabolic alkalosis?

Answer 21

Vomiting and gastric drainage.

Question 22

What are some alkali gain causes of metabolic alkalosis?

Answer 22

Cl or K depletion via diuretics, mineralocorticoid excess, bicarb gain, and organic anions via blood transfusion.

Question 23

Describe the relationship between K+ and H+ in cells.

Answer 23

They oppose each other in a way; hypokalemia may draw more H+ into the cell, and high proton content leads to proton entering the cell, which may drive K+ out of the cell.

Question 24

What are acute causes of respiratory acidosis?

Answer 24

Sudden airway obstruction, chest trauma, acute paralysis, depression of CNS respiratory centers.

Question 25

What are chronic causes of respiratory acidosis?

Answer 25

COPD, pulmonary fibrosis.

Question 26

Describe pH, HCO3, and pCO2 in respiratory acidosis.

Answer 26

High bicarb, low pH, high pCO2.

Question 27

Describe pH, HCO3, and pCO2 in respiratory alkalosis.

Answer 27

High pH, low pCO2, low bicarb.

Question 28

Which acid-base disorder can we cause acutely by ourselves?

Answer 28

Respiratory alkalosis via hyperventilation.

Question 29

A patient has cerebral edema. Which breathing mechanism would you want to induce?

Answer 29

Respiratory alkalosis; this decreases flow to relieve intracranial pressure.

Question 30

Describe aspirin overdose.

Answer 30

A mixed disorder beginning with respiratory alkalosis followed by metabolic acidosis.