Respiratory Physiology III Flashcards
How does hypercarbia impact PaO2?
It reduces PaO2
We can see from the alveolar gas equation that an increase in CO2 will displace alveolar O2, resulting in hypoxemia
How does cardiac tissue react to hypercarbia?
Depends on how severe it is
CO2 is a direct myocardial suppressant
BUT
Hypercarbia stimulates SNS impulses which increase contractility and HR, which usually overrides the myocardial suppressant effects UNLESS hypercarbia is extreme
What changes will you see on an EKG when a patient is hypercarbic?
Tachycardia
Prolonged QT
Dysrhythmias
How does CO2 impact vasculature in the periphery?
In the lungs?
In the periphery, it vasodilates
In the lungs, it vasoconstricts
How does hypercarbia impact potassium levels?
Calcium levels?
Both will increase
Ca competes with H for binding on plasma proteins. An increase in H buffering will result in increased free Ca
In acute respiratory acidosis, how does PaCO2 predict pH?
For every 10mmHg rise above 40 in PaCO2
pH will decrease by 0.08
In chronic respiratory acidosis, how does PaCO2 predict pH?
For every 10mmHg rise above 40 in PaCO2
pH will decrease by 0.03
Where in the body is CO2 primarily monitored?
The central chemoreceptor in the medulla
What are secondary CO2 monitoring sites in the body?
Carotid Bodies
Transverse Aortic Arch
In the CO2 ventilatory curve, a shift to the right means:
The body is LESS sensitive to PaCO2, resulting in ACIDOSIS
In the CO2 ventilatory curve, a shift to the left means:
The body is MORE sensitive to PaCO2,
Causing alkalosis
What are some causes of a Left shift in the CO2 curve?
A Right Shift?
When does CO2 become a respiratory depressant?
PaCO2 greater than 80-100
What is the body’s respiratory pacemaker?
The dorsal respiratory center
The apneustic center ______ the DRG
The pneumotaxic center ______ the DRG
Where are peripheral chemoreceptors located?
Carotid bodies at the bifurcation of common carotid and the aortic arch
How do peripheral chemoreceptors respond to hypoxemia?
