Acid-base abnormality Flashcards
Acid-base abnormality refers to a disruption in the body’s balance of acids and bases, often reflected in an alteration of arterial blood pH. Which of the following is normal for pH of the blood?
1 - 7.50-7.80
2 - 7.35-7.80
3 - 7.35-7.45
4 - 7.15-7.45
3 - 7.35-7.45
- <7.35 = acidosis
- > 7.45 = alkalosis
What is the normal range for partial pressure of oxygen (PaO2), which is a measurement of the pressure of oxygen in arterial blood (essentially oxygen dissolved in the blood)?
1 - 10.7 - 13.3kPa
2 - 8.0 - 10.3kPa
3 - 4.7 - 6.0kPa
4 - 10.7 - 11.7kPa
1 - 10.7 - 13.3kPa
What is the normal range for partial pressure of oxygen (PaCO2), which is a measurement of the pressure of carbon dioxide in arterial blood (essentially oxygen dissolved in the blood)?
1 - 10.7 - 13.3kPa
2 - 8.0 - 10.3kPa
3 - 4.7 - 6.0kPa
4 - 3.5 - 6.0kPa
3 - 4.7 - 6.0kPa
Which of the following is the best indicator of hypoxia and respiratory failure?
1 - PaCO2
2 - bicarbonate
3 - PaO2
4 - lactate
3 - PaO2
Which of the following indicates type 1 respiratory failure?
1 - low PaO2 and PaCO2
2 - high PaO2 and low PaCO2
3 - low PaO2 and normal PaCo2
4 - high PaO2 and PaCO2
3 - low PaO2 and normal PaCo2
Which of the following indicates type 2 respiratory failure?
1 - low/normal PaO2 and low PaCO2
2 - low PaO2 and high PaCO2
3 - low/normal PaO2 and normal PaCo2
4 - high PaO2 and PaCO2
2 - low PaO2 and high PaCO2
pH can be:
- acidotic <7.35
- normal 7.35 - 7.45
- alkalotic >7.45
Then we need to decide if the cause is respiratory or metabolic. Which of the following indicates a respiratory acidosis?
1 - normal pH and high PaCO2
2 - low pH and low PaCO2
3 - low pH and high PaO2
4 - low pH and high PaCO2
4 - low pH and high PaCO2
- CO2 is retained and increases acidity of the blood
- carbonic anhydrase converts the CO2 and H2O into carbonic acid, which increases blood acidity
Bicarbonate is produced by the kidney and acts as a buffer to neutralise the acid in the blood. Is the production of bicarbonate a fast or slow process?
- slow process
Therefore changes in bicarbonate in response to acidic pH of the blood is slow to respond
Unable to compensate in acute respiratory acidosis
If bicarbonate is raised, which of the following does this typically indicate?
1 - chronic respiratory acidosis
2 - acute respiratory alkalosis
3 - acute respiratory acidosis
4 - chronic respiratory alkalosis
1 - chronic respiratory acidosis
Bodies response to compensate for CO2 retention
Common in COPD
Raised bicarbonate is common in COPD to compensate for CO2 retention and respiratory acidosis. But is the kidney able to increase bicarbonate production sufficiently in a COPD exacerbation?
- No
Which of the following occurs to cause respiratory alkalosis?
1 - high RR that increases CO2 expiration
2 - high RR that reduces O2 inspiration
3 - low RR that reduces CO2 expiration
4 - bicarbonate loss in the urine
1 - high RR that increases CO2 expiration
Common in:
- hyperventilation syndrome (normal PaO2)
- PE (low PaO2)
Which of the following occurs in metabolic acidosis?
1 - low pH and low PaO2
2 - low pH and high PaCO2
3 - low pH and low bicarbonate
4 - low pH and high bicarbonate
3 - low pH and low bicarbonate
Which of the following would NOT cause metabolic acidosis?
1 - high lactate (anaerobic respiration)
2 - high ketones (DKA)
3 - vomiting and nausea
4 - high H+ (renal failure, rhabdomyolysis)
5 - diarrhoea and renal failure
3 - vomiting and nausea
Typically leads to metabolic alkalosis
Which of the following occurs in metabolic alkalosis?
1 - high pH and low PaO2
2 - high pH and high PaCO2
3 - high pH and low bicarbonate
4 - high pH and high bicarbonate
4 - high pH and high bicarbonate
Which of the following would NOT cause metabolic alkalosis?
1 - low H+
2 - high aldosterone
3 - high lactate
3 - high lactate
High aldosterone can lead to metabolic alkalosis due to excretion of H+ ions. Which 2 of the following conditions can cause high aldosterone?
1 - lung cancer
2 - conns syndrome
3 - heart failure
4 - COPD
2 - conns syndrome
3 - heart failure
High aldosterone can lead to metabolic alkalosis due to excretion of H+ ions. Which 2 of the following medications can cause high aldosterone?
1 - furosemide
2 - bisoprolol
3 - bendroflumethiazide
4 - ramipril
1 - furosemide
3 - bendroflumethiazide
What is the normal range for base in the blood?
1 - -4 to +8
2 - 0 to +4
3 - -2 to +2
4 - +2 to +6
3 - -2 to +2 mEq/L
Negative value <-2 = base deficit
- indicates metabolic acidosis
Positive value >+2 = base excess
- indicate metabolic alkalosis
Anion gap calculation:
(Na+ add K+) - (Cl- add HCO3-)
Na+ and K+ = cations
Cl- and HCO3- = anions
Normal anion gap:
3 - 11 MEQ/L
The anion gap should have equal cations and anions.
This is because the blood in our body is also neutral.
BUT this is not the case because the formula does NOT account for other anions like:
- phosphate
- albumin
- sulphate
- organic acids
Therefore the anion gap is measuring the above anions in the blood
If there is a high anion gap, this means that there is something in the unknown anions category that has increased causing a higher than usual anion gap. What of the following may cause this?
1 - lactate
2 - ketoacids
3 - formic acid
4 - oxalic acid
5 - all of the above
5 - all of the above
- lactate = lactate acidosis (Salicylate poisoning or aspirin, and shock
- ketoacids = DKA
- formic acid = methanol poisoning
- oxalic acid = ethylene glycol poisoning
Essentially these are all due to higher organic acids being produced or ingested
If there is a normal anion gap, this means that there is something missing in the anions category. What is this typically?
1 - Cl-
2 - organic acids
3 - phosphate
4 - bicarbonate
4 - bicarbonate
Results by an increase in Cl- to compensate
Loss of bicarbonate is most commonly due to diarrhoea and renal tubular acidosis
