What is bradypea or respiratory depression ?

The Medical Definition is: abnormally slow breathing. The normal rate of respirations (breaths per minute) depends on a number of factors, including the age of the individual and the degree of exertion.
MedicineNet .

Paula never knew she had bradypnea. Didn’t even suspect. So no one else knew either. She wasn’t in distress.

Breathing rate is handled by the autonomic nervous system, the brain stem specifically. Paula’s slow breathing was not visible, it was not conscious. It was indistinguishable from eupnea – normal unlabored breathing. Yet her breathing was not entirely unlabored. Paula used active exhaling, which is usually very abnormal. Exhaling is supposed to be a passive process, with your lungs letting out air naturally, as a balloon does when opened. Paula had to use effort to push out the air in her lungs, using her abdominal muscles. Paula was aware that it took work for her to breathe, she thought that this was normal for everyone. This is not normal.

Paula does not know when she developed bradypnea. She might always have had abnormally slow breathing since her tumultuous birth and not known it. Or maybe she began having bradypnea in adulthood or maybe it started when she became sick with depressive insanity. It is hard to say since she is unaware of her bradypnea. Still. Unless she counts her respirations.

Bradypnea is also known by the term respiratory depression. Respiratory depression can be caused by drugs like opioids or anaesthetics and cause [reversible] altered mental status and mental confusion. Respiratory depression can also be the result of central nervous system injury and may cause no symptoms at all. I get the impression from looking at the literature on respiratory depression, that not much about it is understood. Even less is understood about people who breathe this way normally, people like Paula. For Paula, at least for the past 25 years that she has known of it, bradypnea is a part of her normal vital signs. When healthy, Paula has normal blood pressure, normal pulse, no abnormal heart signs, normal body temperature and normal mental status [reflecting her university education and her grades ] AND bradypnea. When healthy, Paula breathes at the rate of 5 breathes per minute. Her slow breathing seems to present no problem, as long as she is well enough to keep it up, it seems.

The difficulty with this is that doctors believe that bradypnea suggests that death is close, that death is imminent. Doctors have never studied bradypnea in normal healthy adults, because they have never heard of it; they have only seen bradypnea in patients who are near death or dying. This is not the case with Paula.

This is why I have followed Paula so closely for the past 25 years. This is why I think that cases like Paula’s are very important, very significant. How is it that Paula is alive, not to mention very fit?. What has happened to her at the physiological and anatomical level? Is she “hypoxia tolerant”, like certain fish and turtles? What have we learnt from studying hypoxia tolerant fish and turtles? A lot, I think.

” Hypoxia-induced physiological modifications that increase oxygen extraction capacity…. are observed in fishes that frequently encounter hypoxia.” A new analysis of hypoxia tolerance in fishes using a database of critical oxygen level (P_crit) Nicholas J Rogers, Mauricio A Urbina, Erin E Reardon, David J McKenzie, and  Rod W Wilson, Conserv Physiol. 2016; 4(1): cow012. Published online 2016 Apr 27. doi: 10.1093/conphys/cow012PMCID: PMC4849809PMID: 27293760

Since it seems that healthy hypoxia-tolerent fish have developed physiological and anatomical changes allowing them to take in enough oxygen under difficult breathing conditions, could this be true of Paula? Is this why her slow breathing is sufficient enough? I don’t know. It does look likely, though. Who is to say that the brain and body can’t make physiological adjustments to allow effective and efficient bradypnea in the face of central nervous system injury preventing more conventional resting breathing rates. Again Shakespeare reminds us “There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.”  It seems like we should look into the “complex motor act of baseline breathing rate at rest” more closely.

I have learnt from doing research on breathing that abnormally slow breathing can be very a very effective way to breathe, contrary to notions of most doctors. This way of breathing reduces dead space the most. But Paula’s breathing is too slow for facile explanations and we need to study this phenomena more carefully

Looking more closely at the brain stem’s decisions about respiratory rate and depth, tells us a lot about the handling of gases and nutrients in the body. Metabolic problems regarding the handling of these chemicals internally is a well known cause of dysfunction of mind. Yet the study of mind is still mainly philosophical and psychological instead of biological. Mind is certainly derived from the products of metabolism. This involves the function of the whole body not just the brain, It involves internal ratio’s, pressure and temperature of substances, carefully orchestrated to keep us alive by the brain stem and the autonomic nervous system. Breathing is key somehow and breathing and internal conditions are guided by levels of internal carbon dioxide. Not investigating the biology of the body in the study of mind is, I have long thought, naive and ignorant, misleading and doomed to fail..

Counting peoples breathing rates, along with their other vital signs at rest would be a start; in health and in illness, especially neurological illness, including manic depressive insanity. It has been reported that abnormal breathing is a factor in illnesses such as Parkinson’s, Alzeihmer’s and of course diseases which cause neurodegeneration and respiratory motor weakness.

Is bradypnea or respiratory depression the same as Hypoventilation ? The answer is no. Hypoventilation is too slow breathing which causes hypercapnia. Paula’s abnormally slow yet effective breathing [bradypnea] did not lead to any problems. She seemed to get sufficient oxygen and was able to exhale carbon dioxide very effectively, if unconventionally. Carbon dioxide is a normal by-product of food metabolism. If the ability to exhale carbon dioxide is weakened, carbon dioxide is retained in the blood and has toxic effects including: dyspnea or * anguish , acidosis and altered consciousness. When Paula’s slow but strong breathing was weakened by poor health [probably due to infection] , she lost her mind and felt awful. She immediately became aware of the anguish caused by ineffective breathing, yet she was still unaware that her breathing was in any way abnormal.

* see Post on the topic of mental anguish and dyspnea

Her other vital signs became abnormal as well. Her blood pressure shot up and remained very high, and she had palpitations, heart murmurs and other arrhythmia’s, and became vasoconstricted.. [she developed pale, cold, even blue hands, feet and lips]. These are signs of sympathetic activation- from possible hypercapnia, hypothermia and/or internal bleeding or some combination of all three. Sympathetic activation is normally thought of as the Stress Response that occurs when we are psychologically frightened or angry. Sympathetic activation also occurs in response to blood loss, injury, surgery, circulatory problems, hypothermia, hyperthermia, fever, iron deficiency, infection, difficulty breathing, hypercapnia, and any other physical stressors that threaten physical conditions necessary to continue being alive. Br J Anaesth, 85 (1), 109-17 Jul 2000 The Stress Response to Trauma and Surgery, J P Desborough  PMID: 10927999 DOI: 10.1093/bja/85.1.109

No one knew any of this. No one checked any of her vital signs. No one wanted to, I think. They were too scared. They wouldn’t have known what to do. Most doctors do not know how to identify medical emergencies, much less treat them.

The way to tell if carbon dioxide is present in toxic amounts in the blood is for the doctor to perform an invasive and painful test called an arterial blood gas test. The measurement of the partial pressure of carbon dioxide in the arterial blood , the PCO2, is the only way to tell if bradypnea has developed into hypoventilation.

Hypoventilation and respiratory acidosis will require drugs and techniques and tools to help a person move air in and out more effectively. Success is when the altered mental status returns to one’s normal mental status. and vital signs return to normal [with the possible exception of bradypnea-which may or may not be permanent.

This is how Paula regained her mind and stopped the sensation of dyspnea [ or that of anguish, as she described it]. The drug that helped her eventually [although it took much too long] was Paxil, a serotonin booster or agonist. How could this be ? How could a serotonin booster help Paula move air in and to more effectively over the long term?