Hyperpnea vs. hyperventilation

[sgv]

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I'm having the hardest time differentiating these two. The textbook (Rhoades/Pflanzer) appears to have a typo but I would like a confirmation from you all.

"1. Alveolar ventilation is increased, which results in "blowing off" excess CO2 and thereby decreasing arterial PCO2 back to normal.
2. This increase in ventilation is known as hyperpnea.
3. A distinction must be made between the terms hyperpnea and hyperventilation.
4. Hyperpnea indicates increased minute ventilation but without a change in arterial PCO2, whereas hyperventilation means increased alveolar ventilation with a concomitant decrease in arterial PCO2."

Sentence 1 and clearly says that hyperpnea involves a decrease in arterial PCO2 yet sentence 4 says hyperpnea does not involve a change in arterial PCO2.

What is going on? Did they mean to say hyperventilation instead of hyperpnea?

 

[ChEMD]

It's correct. Hyperpnea is an increase in ventilation to maintain a normal pCO2 (typically due to increased CO2 production). Hyperventilation is an increase in ventilation beyond the normal need (based on the level of CO2 production), causing an abnormal decrease in pCO2.

Edit: so with hyperpnea, there may be a transient increase pCO2 due to increased CO2 production, but it quickly goes back down to normal because you begin to ventilate more. The key difference is that pCO2 doesn't decrease beyond normal (40 mmHg arterial) in hyperpnea, but it does in hyperventilation.

 

[sgv]

It's correct. Hyperpnea is an increase in ventilation to maintain a normal pCO2 (typically due to increased CO2 production). Hyperventilation is an increase in ventilation beyond the normal need (based on the level of CO2 production), causing an abnormal decrease in pCO2.

Edit: so with hyperpnea, there may be a transient increase pCO2 due to increased CO2 production, but it quickly goes back down to normal because you begin to ventilate more. The key difference is that pCO2 doesn't decrease beyond normal (40 mmHg arterial) in hyperpnea, but it does in hyperventilation.

Thanks! I think I understand now. When arterial CO2 is abnormally high, hyperpnea increases ventilation to expel arterial CO2 down to normal levels whereas hyperventilation has excessive ventilation to the point that arterial CO2 drops down below normal levels.

 

[ChEMD]

Thanks! I think I understand now. When arterial CO2 is abnormally high, hyperpnea increases ventilation to expel arterial CO2 down to normal levels whereas hyperventilation has excessive ventilation to the point that arterial CO2 down below normal levels.

Yup, you got it!