WILTIMS #82: Don't Panic

TIL: Giving supplemental oxygen (O₂) may increase the arterial oxygen saturation but it does nothing to decrease the partial pressure of carbon dioxide in the arterial blood (P_aCO₂). Instead you must change the respirator settings to increase the alveolar ventilation (the amount of air that comes in and out of the lungs).

If hyperventilating get the CO₂ out of your body faster, why is it so bad? Your body does not monitor its blood oxygen level directly, but instead looks at the carbon dioxide level which, theoretically, should be just as effective. If the CO₂ level is high, O₂ should be low and vice versa. The problem is that hyperventilation causes the CO₂ level to go down without affecting the O₂ level. The body responds by constricting blood vessels in the brain and other tissues, thinking that O₂ must be abundant, effectively suffocating itself. This is why breathing into a bag when hyperventilating can help; it traps more CO₂ in the lungs - normally a bad thing - to alert your brain to the real O₂ level.

Why doesn't hyperventilating increase your blood oxygen levels? O₂ is transported via the hemoglobin protein in red blood vessels and, at normal respiration rates, the hemoglobin are already saturated with O₂. They can't hold any more O₂, even if you are breathing more in per minute.

X-linked agammaglobulinemia (yes, I occasionally pick things to share just because they have sufficiently multisyllabic names) is a genetic immune deficiency resulting from a mutation to the X chromosome that prevents B cells from maturing. B cells are responsible for producing antibodies which are the primary weapon the immune system has to fight off pathogens. The disease is expressed far more often in males due to the X-linked recessive inheritance. As women have two X chromosomes, a woman with one diseased allele will not show symptoms but will instead be a carrier of the disease. Men (who have one X and one Y chromosome) can never be carriers and will always fully express the diseased phenotype.