Acid-Base Balance

Question 1

What hormone is the primary regulator of electrolyte concentrations?

Answer 1

Aldosterone.

Question 2

What is an example of an isotonic solution? How does this act on other fluids in the body when administered into the bloodstream?

Answer 2

0.9% normal saline is an isotonic solution. Isotonic solutions stay in the intravascular space because they are the same concentration as the body’s fluids.

Question 3

What is an example of a hypotonic solution? How does it act on other fluids in the body when administered into the bloodstream?

Answer 3

D5W is a hypotonic solution. Hypotonic solutions generally flow from blood vessels into cells because they want to flow into more concentrated solutions (such as in the cell).

Question 4

How do hypertonic solutions act on other fluids in the body when administered into the bloodstream?

Answer 4

A hypertonic solution wants to draw less concentrated solutions into itself. It tends to draw fluids out of the cells and into the bloodstream.

Question 5

What 3 chemical systems exist in the body to regulate acid/base balance? Are they fast acting? Or slow acting?

Answer 5

1. Carbonic acid/bicarbonate system
2. Phosphate buffering system
3. Protein buffering system

All are fast acting compared to physiological mechanisms such as respiration and urinary elimination.

Question 6

You are treating a patient who is taking deep, rapid respirations. What pattern of breathing is this? Why are they likely doing this?

Answer 6

This pattern of breathing is called Kussmaul’s respirations and is a natural countermeasure to increase blood pH by trying to expel as much CO2 as possible.

Question 7

What is meant by “respiratory acidosis”? Give one example of a mechanism which could cause this.

Answer 7

Failure to eliminate CO2 through breathing can cause acidosis. This can occur for a variety of reasons including but not limited to:
- TBI
- Spinal injury
- Major pneumothorax
- COPD
- Overdose
- Anything causing apnea really…

Question 8

What is meant by “metabolic acidosis”? Give one example of a mechanism which could cause this.

Answer 8

All non-respiratory causes of acidosis. These causes could include:
- Poisoning
- Sepsis
- Renal failure
- Ingestion of acids
+ Any others you can justify!

Question 9

What is meant by “respiratory alkalosis”? Give one example of a mechanism which could cause this.

Answer 9

Hyperventilation can cause excess CO2 elimination resulting in alkalosis. This can occur for a variety of reasons including but not limited to:
- Minor pulmonary embolism
- Minor pneumothorax
- Anxiety -> hyperventilation
+ Any others you can justify!

Question 10

What is meant by “metabolic alkalosis?” Give one example of a mechanism which could cause this.

Answer 10

All non-respiratory causes of alkalosis. These are rare in the field but could be from:
- Vomiting
- Poisoning
+ Any others you can justify!