Respiratory Alkalosis

Question 1

What is respiratory alkalosis?

Answer 1

• Characterised by reduced PaCO2,
• normally or slightly reduced serum bicarb and raised pH

Question 2

What is acute respiratory alkaloids?

Answer 2

• Serum bicarb decreases by 2mM for every 10mmHg decrease in PaCO2

Question 3

What is chronic respiratory alkalosis?

Answer 3

1. Serum bicarb reduction of 5mM for every 10mHg decrease in PaCO2
2. If Serum bicarb higher than expected then mixed metabolic and respiratory alkalosis
3. If serum bicarb lower than expected then mixed metabolic acidosis and respiratory alkalosis

Question 4

What can cause Respiratory alkalosis?

Answer 4

1. Stress ventilation
2. Hypoxic stimulation to ventilation: alveolar disease, right to left shunts, altitude
3. Drug induced stimulus to hyperventilation: early salicylate poisoning in adults, less in kids
4. Pregnancy
5. Stroke, subarachnoid hemorrhage, encephalitis

Question 5

What does salicylate overdose lead to?

Answer 5

1. Mixed respiratory alkalosis and metabolic acidosis
2. Early stimulation of the respiratory centre leads to a respiratory alkalosis
3. Later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis