What is Chemoreceptor reflex? In human nervous system: Reflex pathways. Overall, the chemoreceptor reflex regulates respiration, cardiac output, and regional blood flow, ensuring that proper amounts of oxygen are delivered to the brain and heart. Chemoreceptor reflex | physiology | Britannica
It seems that the reflex causing breathing rate to rise with the stimulus of carbon dioxide in the blood is broken. ..who knew it could break? There are important sensors in the periphery – the neck, the larynx, the vocal cords, the torso, etc…They are unprotected and easily damaged, we think.
Dr Emile Kraepelin suggested that patients with manic depressive insanity had defective ventilatory systems. Dr Kraepelin counted the respiratory rates of his patients and found them too slow in depressive episodes and too fast and periodic in manic ones. He understood that the syndrome involved difficulty managing PCO2 due to this defect. Today we have treatments for this.
Modern doctors do not measure breathing rates even though it takes one minute and a stopwatch. Why? Breathing at rest is involuntary, dictated by the brain stem in concert with PCO2.
My friend Paula found out accidentally that her breathing rate was very slow in full health. [she found out when taking a basic first aid class for work.] The range of breathing rates in the class was very wide, from as low as 3 breaths per minute to as high as 28 breaths per minute at rest, awake and in health. That is fascinating. Interestingly, people at both extremes of breathing rates were clever and were restless and loud and a little disruptive.
Carbon dioxide is a cerebral vasodilator, and a possible delirient, intoxicant and asphyixiant.
It could easily be the cause of bipolar attacks.
Kraepelin expected doctors to continue this line of research. His definition for manic depressive insanity was that attacks usually lifted spontaneously, but without any available treatments back then, the attacks might last months, years, or decades before remitting. The effects of carbon dioxide are known to be reversible unless you die.
Paula feels normal, she looks normal, no one can tell she has this respiratory defect. It turns out that she was anoxic when born, was suctioned [had swallowed meconium-could this have changed her gut microbiome?] and was resuscitated and then developed normally.
Why have doctors forgotten Kraepelin’s careful studies?
Why do we not measure respiratory rate in health and when challenged by illness?
[Paula’s RR does not increase when she is sick….this presents a problem for keeping PCO2 to normal levels in the blood.].
Why are we the only ones besides Kraepelin to have discovered this?
Because Paula does not recognize the source of her distress as stemming from the respiratory defect she does not know she has. …. And she never looks like she is in respiratory distress, there is no shortness of breath…although when sick she can barely talk more than a few words or think properly, these are known nonspecific signs of respiratory distress.
We have treatments today to help clear the airways and antibiotics for infection and bronchodilators to open the airways and CPAP to help the motor act of breathing.
Why is there no research on respiratory defects which make acid base of the blood more difficult, especially when exposed to higher CO2 levels or when one is ill with the flu and cannot recover easily without supportive medical care.
Paula did have one long episode of bipolar depression and it was exactly as Kraepelin reported from seeing thousands of patients [also with respiratory depression like Paula], it was nothing like the DSM reports. Kraepelin was an excellent observer of the natural course of the illness, in the days before medications.
Paula has been fine for 20 years [her breathing rate is still too slow and her lungs healthy with a tidal volume of .5 L per breath- normal for someone in their 60’s.Her doctors cannot explain how it is that she only exchanges 1.5 L or air per minute instead of the assumed 6-8 L per minute.]
She seems to be a different phenotype of human, as are Kraepelin’s thousands of bipolar depressed patients back in the 1900’s.