When studying up on autoset technology I found mentioned the
Hering -Breuer Reflex (not something I can remember from my distant anatomy and physiology lectures). This is the reflex that limits excessive expansion and contraction of the chest during respiration prior to sending impulses to the brain via the vagus nerve.
Joseph Breuer (15 Jan 1842-20 June 1925) was an Austrian Physicist whose achievements included being a father of five children and showing how the sense of balance functions. He also undertook psychoanalytic work with friend Sigmund Freud and documented a study supporting “the talking cure” where patient’s symptoms were reduced or disappeared just by describing them to him. He was also responsible for changing the way scientists viewed the relationship between the lungs and nervous system.
In 1868, Breuer and Hering reported that a maintained distention of the lungs of anesthetized animals decreased the frequency of the inspiratory effort or caused a transient apnoea. The stimulus for this reflex is pulmonary inflation.
There are both inflation and deflation reflexes that help regulate the rhythmic ventilation of the lungs, thereby preventing over distension and extreme deflation. These reflexes arise outside the respiratory centre in the brain; that is, the receptor sites are located in the respiratory tract, mainly in the bronchi and bronchioles. They are activated by either a stretching or a nonstretching and compression of the lung; the impulses are transmitted from the receptor sites through the vagus nerve to the brainstem and thence to the respiratory centre.The inflation reflex acts to inhibit inspiration and thereby prevents further inflation. When the lung tissue is stretched by inflation, the stretch receptors respond by sending impulses to the respiratory centre, which in turn slows down inspiration. As the expiratory phase begins, the receptors are no longer stretched, impulses are no longer sent, and inspiration can begin again. This is called the Hering–Breuer deflation reflex. It is also believed that in addition to the cessation of impulses from the stretch receptors, there may be an activation of compression receptors which transmit impulses that inhibit expiration, thus allowing inspiration to begin.
The relevance of this and APAP therapy is that some autosets are programmed to not respond to apnoeas above 10cm H2O since these episodes are more likely to be central in nature. The rationale used is that higher pressures will cause the Hering-Breuer reflex and if the pulmonary stretch receptors get overstretched they send a signal to the brain to stop breathing, leading to more central events.
Users should understand though that pressure does still increase in response to obstructive hypopnoeas, snoring and flow limitation.
Hering -Breuer Reflex (not something I can remember from my distant anatomy and physiology lectures). This is the reflex that limits excessive expansion and contraction of the chest during respiration prior to sending impulses to the brain via the vagus nerve.
Joseph Breuer (15 Jan 1842-20 June 1925) was an Austrian Physicist whose achievements included being a father of five children and showing how the sense of balance functions. He also undertook psychoanalytic work with friend Sigmund Freud and documented a study supporting “the talking cure” where patient’s symptoms were reduced or disappeared just by describing them to him. He was also responsible for changing the way scientists viewed the relationship between the lungs and nervous system.
In 1868, Breuer and Hering reported that a maintained distention of the lungs of anesthetized animals decreased the frequency of the inspiratory effort or caused a transient apnoea. The stimulus for this reflex is pulmonary inflation.
There are both inflation and deflation reflexes that help regulate the rhythmic ventilation of the lungs, thereby preventing over distension and extreme deflation. These reflexes arise outside the respiratory centre in the brain; that is, the receptor sites are located in the respiratory tract, mainly in the bronchi and bronchioles. They are activated by either a stretching or a nonstretching and compression of the lung; the impulses are transmitted from the receptor sites through the vagus nerve to the brainstem and thence to the respiratory centre.The inflation reflex acts to inhibit inspiration and thereby prevents further inflation. When the lung tissue is stretched by inflation, the stretch receptors respond by sending impulses to the respiratory centre, which in turn slows down inspiration. As the expiratory phase begins, the receptors are no longer stretched, impulses are no longer sent, and inspiration can begin again. This is called the Hering–Breuer deflation reflex. It is also believed that in addition to the cessation of impulses from the stretch receptors, there may be an activation of compression receptors which transmit impulses that inhibit expiration, thus allowing inspiration to begin.
The relevance of this and APAP therapy is that some autosets are programmed to not respond to apnoeas above 10cm H2O since these episodes are more likely to be central in nature. The rationale used is that higher pressures will cause the Hering-Breuer reflex and if the pulmonary stretch receptors get overstretched they send a signal to the brain to stop breathing, leading to more central events.
Users should understand though that pressure does still increase in response to obstructive hypopnoeas, snoring and flow limitation.
Irene
Hey, I just discovered your blog. Very useful information here, and interesting. I'll be back.
ReplyDeleteAlso, I'm adding your blog to my blogroll.
I'm interested in, but hopeless with, eponyms. Thanks for this, Irene. All APAP machines are not the same.
ReplyDelete