16: Respiratory Adaptations Flashcards
Hypoxia vs anoxia vs hypoxemia
Hypoxia: inadequate oxygen available for tissues
Anoxia: total absence of oxygen to tissues
Hypoxemia: low oxygen in the blood
Four forms of hypoxia
Hypoxic, anemic, circulatory, histotoxic
Hypoxic hypoxia and what can cause it
PaO2 below normal; due to reduced PO2 / blood cannot fully equilibrium with the alveolar air
Anemic hypoxia and what can cause it
Oxygen carrying capacity of blood is reduced; due to anemia or CO poisoning
Circulatory hypoxia and what can cause it
Heart cant pump enough blood to tissues; due to sickle cell anemia, blood clots
Histotoxic hypoxia and what causes it
Tissue unable to utilize oxygen, due to cyanide or other toxins
How do central chemoreceptors work
Detect changes in H ions in the CSF to determine levels of arterial CO2
Which do chronic disease pts develop first; hypoxia or hypercapnia?
Hypoxia
What happens when a chronic disease pt develops hypoxia?
Stimulates chemoreceptors to increase ventilation -> PaCO2 will fall while PaO2 is corrected -> low PaCO2 will cause high pH
Resetting the central chemoreceptors during a low CO2 period
Central chemoreceptors will bring the pH of the CSF back to normal value via the choroid plexus, basically just accepting the low CO2 as normal bc we have to favor maintaining O2 levels over PaCO2 levels
Acclimatization
Long-term response to chronic hypoxia and hypocapnia that occurs over several days-weeks of decreased barometric pressure
When does altitude sickness occur?
Within ours of arriving at increased altitude, and lasts about one week
S/S altitude sickness
HA, irritability, insomnia, dyspnea, N/V, possible pulmonary edema
What causes altitude sickness?
Cerebral blood vessels vasodilate to bring more blood to the brain -> increased perfusion pressure and increased filtration -> mild cerebral edema
Hyperbaric oxygen treatment
Giving 80-100% O2 to treat things like CO poisoning
