Paula is an example of a “natural experiment”

A natural experiment is an empirical study in which individuals (or clusters of individuals) are exposed to the experimental and control conditions that are determined by nature or by other factors outside the control of the investigators. Natural experiment – Wikipedia

Paula was injured either during her difficult birth or during some later time. The result was damage to the centres in the brain or in the neck or elsewhere allowing normal movement of air in and out of the lungs. Paula’s lungs are normal. But Paula has to use her entire body as a “breathing assist device in order to move air in and out in order to remain alive. Somehow, Paula is not really aware that she does this- it is the only way she has ever been able to ventilate [move air in and out of the lungs]. If she thinks about it [which she doesn’t because it is automatic and involuntary], she will say that breathing or ventilating is hard work. [this in medicine means that she has increased work of breathing at rest when awake. If you examine her closely you can see why her breathing is so slow and infrequent. She must squeeze out all the air she can by actively pushing air out with her abdominal muscles. This is not a good thing. This means that when well, at rest she has to work hard to exhale [this takes a long time] and needs the extra push to inhale. And she does not breath any deeper than you and I. Her tidal volume is .5 Litres which is normal.

This injury also broke the reflex that increases breathing rate when anxious or scared or when facing a respiratory challenge or illness or partial obstruction [eg secretions]. This is very bad. This means that she cannot fight an attack of respiratory acidosis in the normal way. Increasing her breathing rate as would be necessary is something she cannot do.

This sound dire.

to be continued……


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