Acid Base Balance

Question 1

What are the 4 types of acid-base imbalances?

Answer 1

• respiratory acidosis
• respiratory alkalosis
• metabolic acidosis
• metabolic alkalosis

Question 2

What are the contributing factors to acid-base balances?

Answer 2

• respiratory = lungs = PCO2

- metabolic = kidneys = HCO3-

Question 3

What are the normal, acidic, alkaline and absolute values of pH in the blood?

Answer 3

low absolute value = 6.8
acidic values = 6.8 - 7.35
normal values = 7.35 - 7.45
alkaline values = 7.45 - 7.8
high absolute value = 7.8

Question 4

What happens if pH goes below 6.8 or above 7.8?

Answer 4

Below 6.8 - CNS is depressed, leading to coma then death

Above 7.8 - CNS becomes excited, leading to convulsions then death

Question 5

What is the chemical formula for the carbon dioxide, carbonic acid, bicarbonate processes in the lungs and kidneys?

Answer 5

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

Question 6

What are the normal, acidic and alkaline values of PCO2 in the blood?

Answer 6

alkaline = <35mmHg
normal = 35 - 45mmHg
acidic = >45mmHg
(lots of CO2 = lots of acid = acidosis

Question 7

What are the normal, acidic and alkaline values of HCO3- in the blood?

Answer 7

acidic = <22mEq/L
normal = 22 - 26mEq/L
alkaline = >26mEq/L

Question 8

What are the possible causes of respiratory acidosis? (increased PCO2, lowered pH)

Answer 8

• anything that causes hypoventilation (shallow breathing)
• cystic fibrosis
• pneumonia
• pneumothorax
• tiredness
• hunger

Question 9

What are the possible causes of respiratory alkalosis? (lowered PCO2, increased pH)

Answer 9

• pain, stress (hyperventilation)

Question 10

What are the possible causes of metabolic acidosis? (low HCO3-, low pH)

Answer 10

• liver failure
• too much alcohol
• unmanaged diabetes (ketoacidosis)
• diarrhoea (expels the alkaline bile and pancreatic excretions, leaves the stomach acids)

Question 11

What are the possible causes of metabolic alkalosis? (high HCO3-, high pH)

Answer 11

• excessive antacid use

- prolonged vomiting (expels stomach acid, leaves alkaline bile and pancreatic excretions)

Question 12

What are the three questions to ask to interpret arterial blood gases (ABGs)?

Answer 12

• does the pH indicate alkalosis or acidosis?
• is the cause of the pH imbalance respiratory (lungs, CO2) or metabolic (kidneys, HCO3-)?
• Is there compensation? (partial compensation = pH not in normal range. Full compensation = pH in normal range)