Pulmonary Question - for you physiology wizards

[konquer]

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Does hyperventilation mean faster breathing or more O2 delivery?

For example, if someone is having a panic attack, is he going to breathe fast and shallow (CO2 goes up) or fast and deep at the same time (CO2 goes down)?

 

[FutureInternist]

Does hyperventilation mean faster breathing or more O2 delivery?

For example, if someone is having a panic attack, is he going to breathe fast and shallow (CO2 goes up) or fast and deep at the same time (CO2 goes down)?

I think hyperventilation can mean too fast or too deep.

However, usually, "hyperventilation" is used to mean fast, & shallow as in a panic attack --> Decreased CO2 (which why you pass out since the body's trigger for breathing is NOT too little O2 but rather too much CO2)

The fast & deep breathing is called Kussmal respiration & is used by the body to compensate for a metabolic acidosis i.e. MUDPILERS 🙂 & the body compensates by blowing off the excess acid as CO2. (You are also losing CO2 in this case but since you have an excess, you do not faint)

 

[Zli]

Hm, the way we were taught is that fast breathing = tachypnea, deep breathing = hyperpnea, and tachypnea+hyperpnea=hyperventilation.

 

[scube]

Ventilation = (tidal volume - dead space) * breaths per min, if I am not getting past dead space I am not ventilating.

assuming normal perfusion it can be judged by CO2 levels.
ventilation is related to the amount of CO2 removed. if more CO2 is removed = hyperventilation.
how fast/slow you are breathing is just breathing rate. if someone is breathing twice as fast and still pretty deep and only has one lung they are probably in a normal ventilatory state.

 

[Zli]

if someone is breathing twice as fast and still pretty deep and only has one lung they are probably in a normal ventilatory state.

The thing is, the "depth" of breathing is determined by tidal volume. A person with only one lung would have a pretty tough time trying to take a deep breath.

The term itself was established long before pCO2 levels could be reliably estimated, and a drop in co2 is only a result of a normal person hyperventilating, not it's defining characteristic. Note that one could still hyperventilate and have high co2 if there's an increase in dead space.

 

[scube]

The thing is, the "depth" of breathing is determined by tidal volume. A person with only one lung would have a pretty tough time trying to take a deep breath.

The term itself was established long before pCO2 levels could be reliably estimated, and a drop in co2 is only a result of a normal person hyperventilating, not it's defining characteristic. Note that one could still hyperventilate and have high co2 if there's an increase in dead space.

I didn't say that it was a defining characteristic but all other things being normal its an estimate. and if you increase dead space you decrease ventilation. LOOK at the equation. using breathing rate and visual depth can be miss leading. Also I said the one lung person would "still be breathing pretty deep" ie it would appear as a "full deep breath" and twice as fast would equal normal ventilation ( once again look at the equation) TV cut in half, Rate doubled ie normal ventilation. but if you just look at the patient according to others definitions you would say pt is hyperventalating and you would be wrong.