Acid-Base Imbalance

Question 1

What are the 4 types of acid-base imbalances?

Answer 1

1. Respiratory acidosis
2. Respiratory alkalosis
3. Metabolic acidosis
4. Metabolic alkalosis

Question 2

From what type of vessel is an acid-base gas sample (ABG) obtained?

Answer 2

Through a blood draw on an artery.

The radial artery is the most common.

Question 3

What is the Allen test?

Answer 3

Test is done to make sure the radial artery has good blood circulation to the hand before getting a blood sample for an ABG.

Question 4

What are the steps for doing an Allen test?

Answer 4

1. Apply pressure over ulnar and radial arteries at same time
2. Ask client to open and close hand a few times (hand should blanch/turn white)
3. Release ulnar (keep pressure on radial)
4. Assess color of hand
5. If hand doesn’t turn back to pink within 7 seconds, don’t use it

Question 5

What 3 lab values are used to determine an acid-base imbalance?

Answer 5

1. pH: indicates how acidic or alkaline the blood is.
2. CO₂: indicates how much acid the client is holding onto or getting rid of through the lungs.
3. HCO₃: indicates how much bicarbonate the client is holding onto or getting rid of through the kidneys.

Question 6

What are the normal lab values for pH, CO₂, and HCO3?

When are the abnormal values acidotic or alkalotic?

Answer 6

• pH: (acidotic) ↓ 7.35 - 7.45 ↑ (alkalotic)
• CO₂: (alkalotic) ↓ 35 - 45 ↑ (acidotic)
• HCO₃: (acidotic) ↓ 22-26 ↑ (alkalotic)

Question 7

What are the steps to determine the type of acid-base imbalance?

Answer 7

1. Determine if the pH is acidic or alkalotic (that will determine if the overall imbalance is “acidosis” or “alkalosis”)
2. Determine if both the CO₂ and HCO₃ is acidotic or alkalotic
3. Determine if CO₂ or HCO₃ matches with pH
4. If CO₂ is the same as pH, then the imbalance is “Respiratory”
5. If HCO₃ is the same as pH, then the imbalance is “Metabolic”

Question 8

What is an uncompensated acid-base imbalance?

Answer 8

• only one of the values is abnormal: CO₂ or HCO₃

and

• pH is abnormal

Question 9

What is a compensated acid-base imbalance?

Answer 9

If both CO₂ and HCO₃ are abnormal:

• partially compensated: pH is also abnormal
• fully compensated: pH is normal

Question 10

What is this acid-base imbalance?

pH = 7.32

CO₂ = 50

HCO₃ = 24

Answer 10

Respiratory Acidosis, uncompensated

pH = 7.32 (acidosis)

CO₂ = 50 (acidosis)

HCO₃ = 24 (normal)

Question 11

What is this acid-base imbalance?

pH = 7.50

CO₂ = 32

HCO3 = 24

Answer 11

Respiratory Alkalosis, uncompensated

pH = 7.50 (alkalotic)

CO₂ = 32 (alkalotic)

HCO₃ = 24 (normal)

Question 12

What is this acid-base imbalance?

pH = 7.30

CO₂ = 40

HCO₃ = 19

Answer 12

Metabolic Acidosis, uncompensated

pH = 7.30 (acidosis)

CO₂ = 40 (normal)

HCO₃ = 19 (acidosis)

Question 13

What is this acid-base imbalance?

pH = 7.50

CO₂ = 41

HCO₃ = 28

Answer 13

Metabolic Alkalosis, uncompensated

pH = 7.50 (alkalosis)

CO₂ = 41 (normal)

HCO₃ = 28 (alkalosis)

Question 14

What is this acid-base imbalance?

pH = 7.50

CO₂ = 47

HCO₃ = 28

Answer 14

Metabolic Alkalosis, partially compensated

pH = 7.50 (alkalosis) - abnormal

CO₂ = 47 (acidosis) - abnormal

HCO₃ = 28 (alkalosis) - abnormal

Partially compensated is when both CO₂ and HCO₃ are both abnormal. pH is also abnormal. Only the CO₂ compensated by going into an abnormal range, not the pH - so it was a partial compensation.

Question 15

What is this acid-base imbalance?

pH = 7.36

CO₂ = 50

HCO₃ = 29

Answer 15

Respiratory Acidosis, fully compensated

pH = 7.36 - normal but closer to acidosis

CO₂ = 50 (acidosis) - abnormal

HCO₃ = 29 (alkalosis) - abnormal

Fully compensated is when both CO2 and HCO3 are both abnormal. pH is normal but closer to either acidosis or alkalosis. The HCO₃ compensated by going into the abnormal range, and then the pH compensated by going into the normal range - so it was a full compensation.

Question 16

What are the characteristic signs and symptoms of all acid-base imbalances, regardless of which type?

(Immediate Complication)

Answer 16

• Neuro symptoms: confusion and then coma
• Muscle symptoms: muscle weakness and dysrhythmias

Most of the symptoms are caused by electrolyte imbalances.

Question 17

What is the main electrolyte imbalance for acidosis?

Answer 17

Acidosis = Hyperkalemia

This is due to shifts in acid and electrolytes in the blood and cells.

Question 18

What is the main electrolyte imbalance for alkalosis?

Answer 18

Alkalosis = Hypokalemia and Hypocalcemia

This is due to shifts in acid and electrolytes in the blood and cells.

Question 19

Why do lung diseases cause respiratory acidosis?

Answer 19

Lung diseases cause underventilation because the lungs are not able to expand.

The client is unable to get rid of CO₂ gas, causing acid build-up.

Question 20

Why do narcotics and opioids cause respiratory acidosis?

Answer 20

Narcotics and opioids cause underventilation because the medications suppress respirations.

The client is unable to get rid of CO₂ gas, causing acid build-up.

Question 21

Why does abdominal surgery cause respiratory acidosis?

Answer 21

Abdominal surgery can cause underventilation because the client is in pain and doesn’t want to breathe because it hurts.

The client is unable to get rid of CO2 gas, causing acid build-up.

Question 22

What are the characteristic signs and symptoms for respiratory acidosis?

Answer 22

• underventilation that can occur by decreased or increased respirations
• low O₂ saturation level

Question 23

Why do hyperventilation or panic attacks cause respiratory alkalosis?

Answer 23

Breathing too fast causes the client to breathe out too much CO₂ gas.

Question 24

Why do vomiting and gastrointestinal suction cause metabolic alkalosis?

Answer 24

There is acid in gastric secretions. When there is a loss of gastric secretions, the blood can become more alkalotic.

Question 25

Why does taking **too many antacids** cause metabolic alkalosis?

Answer 25

There is **bicarbonate in antacids**. Taking too many antacids makes the blood alkalotic.

Question 26

Why does **diabetic ketone acidosis (DKA)** cause metabolic acidosis?

Answer 26

DKA is when the blood sugar is very high. The body will use fat cells for energy instead. These **fat cells breakdown into an acid called ketones.** The ketones cause blood to be acidotic.

Question 27

Why does **sepsis** cause metabolic acidosis?

Answer 27

Sepsis is when there is an infection in the blood. **Bacteria break down into acids**, causing the blood to be acidotic.

Question 28

Why does **diarrhea** cause metabolic acidosis?

Answer 28

**Diarrhea results in loss of base**, causing the blood to become more acidic.

Question 29

Why does **chronic kidney disease** cause metabolic acidosis?

Answer 29

**The kidneys are no longer working**. They are unable to get rid of the acid in the blood.

Question 30

How are the acid-base imbalances **treated**?

Answer 30

Because there are many reasons for an acid-base imbalance, try to **figure out the cause** and treat that first.

Question 31

What is a **quick-fix treatment** for metabolic acidosis if the cause is not readily known?

Answer 31

Give **sodium bicarbonate**.