Acid-Base Balance - Key Things To Remember

Front 1

What are the 3 major buffering systems?

Back 1

1. Bicarbonate buffer system
2. Protein buffer system (ex. Hgb)
3. Phosphate & ammonia system (key in nephron for excretion)

Front 2

What is the carbonic acid equation?

Back 2

H+ + HCO3 <--> H2CO3 <--> H2O + CO2

Front 3

What factors to include when explaining the Bicarbonate Buffer System.

Back 3

1. does rxn go right or left
2. occurs rapidly (within minutes)
3. include ph, HCO3, & CO2
4. compensation (not correction)

Front 4

What factors to include when explaining the Respiratory System.

Back 4

1. does run go right or left
2. occurs rapidly (kicks in if bicarbonate system does not fix the problem within a few minutes)
3. include ph, HCO3, & CO2
4. compensation
5. hyperventilation / hypoventilation (focus on CO2 - blows off or retains)

Front 5

What factors to include when explaining the Renal System.

Back 5

1. occurs slowly (few hours to initiate, several days to correct)
2. HCO3 used up and reabsorbed (primary mechanism)
3. H+ excreted (secondary mechanism)
4. correction

Front 6

What is acidosis?

Back 6

1. too much acid
2. low pH (high H+)

Front 7

What is alkalosis?

Back 7

1. too much base relative to acid
2. high pH (low H+)

Front 8

What is PARTIAL compensation?

Back 8

pH remains abnormal

Front 9

What does ABG stand for?

Back 9

Arterial Blood Gas

Front 10

What are the values for ABGs?

Back 10

1. pH
2. HCO3
3. pCO2 or PaCO2
- as well as pO2 & O2 saturation

Front 11

Why analyze arterial gases and not venous?

Back 11

venous blood is used blood that is returning to the heart and is deoxygenated.

Front 12

What are the primary defects associated with metabolic disturbances?

Back 12

problem with either:
H+ or HCO3-

Front 13

What are the primary defects associated with respiratory disturbances?

Back 13

problem with CO2

Front 14

What are the causes of metabolic acidosis?

Back 14

1. Hypoxia
2. Diabetes Complications
3. Aspirin Poisoning
4. Diarrhea

Hint 14

1. anaerobic metabolism to regenerate ATP --> buildup of lactic acid --> increased H+
2. ketone bodies
3. acetylsalicylic acid
4. loss of base (HCO3-) from lower GI tract

Front 15

What are the signs & symptoms of metabolic acidosis?

Back 15

1. Kussmaul's respirations
2. Restlessness
3. Seizures
4. N/V
5. Hyperkalemia

Hint 15

1. Deep, gasping



5. initial buffering: K+ inside exchanged with H+ outside

Front 16

What are the ABG findings for metabolic acidosis?

Back 16

pH = low
HCO3 = low
CO2 = low (partial compensation)

Hint 16

***CO2 - initially increased and reaction goes to the right; respiratory kicks in and causes hyperventilation (blows off CO2) - results in decrease of CO2

Front 17

What is the primary defect for metabolic acidosis?

Back 17

high [H+] relative to HCO3-
- therefore, low pH

Hint 17

****first H+ produced will neutralized by HCO3; eventually, HCO3 is used up and there is too much H+ relative to HCO3-

Front 18

What are the causes of metabolic alkalosis?

Back 18

1. Excessive vomiting
2. Nasogastric suctioning
3. Excessive intake of alkaline drugs (antacids)

Hint 18

1. Lose H+
2. Lose H+
3. Gain base (lose H+)

Front 19

What are the signs & symptoms of metabolic alkalosis?

Back 19

1. Disorientation
2. Muscle Twitches
3. Tetany (muscle spasms)

Front 20

What are the ABG findings for metabolic alkalosis?

Back 20

pH = high
HCO3 = high
CO2 = high (partial compensation)

Hint 20

***CO2 - initially decreased and reaction goes to the left; respiratory kicks in and causes hypoventilation (retains CO2) - results in increase of CO2

Front 21

What is the primary defect for metabolic alkalosis?

Back 21

low [H+] relative to HCO3-
- therefore high pH

Hint 21

****first H+ produced will neutralized by HCO3; eventually, HCO3 is used up and there is too much H+ relative to HCO3-

Front 22

What is the primary defect of respiratory acidosis?

Back 22

high CO2

Hint 22

occurs when respiratory centre is depressed and CO2 is retained

Front 23

What are the causes of respiratory acidosis?

Back 23

1. Head Trauma
2. Over-sedation
3. General Anesthesia
4. Neuromuscular Diseases
5. Obstructive Lung Disease

Hint 23

4. ex. MS, Guillian-Barre

Front 24

What are the ABG findings in respiratory acidosis?

Back 24

pH = low
HCO3 = high (partial compensation)
CO2 = high

Hint 24

(****HCO3 is reabsorbed and H+ is excreted in urine)

Front 25

What is the compensation mechanism for respiratory acidosis?

Back 25

- kidneys will excrete more acid in urine
- increased reabsorption of HCO3-

Front 26

What are the signs and symptoms of respiratory acidosis?

Back 26

1. Lethargy
2. Confusion
3. Disorientation
4. Restlessness
5. Dyspnea (trouble breathing)
6. Tachycardia
7. Dysrhythmias

Front 27

What is the primary defect in respiratory alkalosis?

Back 27

low CO2

Hint 27

hyperventilation - blowing off too much CO2

Front 28

What can cause respiratory alkalosis?

Back 28

1. Excess hyperventilation
2. Anxiety
3. Nervous
4. Agitation
5. Pain

Front 29

What is the compensation mechanism for respiratory alkalosis?

Back 29

- kidneys will excrete more HCO3-

Hint 29

results in low HCO3-

Front 30

What are the ABG values for respiratory alkalosis?

Back 30

pH = high
HCO3 = low (partial compensation)
CO2 = low

Front 31

What are the signs and symptoms of respiratory alkalosis?

Back 31

1. vary with severity of hypocapnea
2. lightheadedness
3. confusion
4. decreased concentration

Hint 31

hypocapnea - reduced carbon dioxide in the blood (can be caused by hyperventilation)

Front 32

How can you tell when the primary cause is metabolic?

Back 32

pH & CO2 move in the same direction

Hint 32

This is important in interpreting ABGs!

Front 33

How can you tell when the primary cause is respiratory?

Back 33

pH & CO2 move in opposite directions

Hint 33

This is important in interpreting ABGs!

Front 34

What things to include on exam for acid-base balance.

Back 34

1. ABG values (explain why for each)
2. Compensation or correction (include initial and final reactions regarding CO2)
3. State if it is a right or left shift and include carbonic equation

Front 35

What is a buffer?

Back 35

a solution that resists changes in pH when acid or alkali is added to it

Front 36

What is a volatile acid?

Back 36

can form a gas (ex. CO2)
- source: metabolism of glucose and fat

Front 37

What happens when pH is changed?

Back 37

- changes ionization which affects: shape and ability to cross cell membrane