O2, CO2 Flashcards
How much hemoglobin is there in 100ml of blood?
12-15mg
Why is CO dangerous?
Higher affinity for hemogloblin than O2
Alters biding affinity of hemoglobin to O2
How do you treat CO poisoning?
Treatment with high O2
What is the Bohr effect?
CO2/H+ are affecting the affinity of hemoglobin for O2
What is the Haldane effect?
O2 is affecting the affinity of hemoglobin for CO2/H+
What factors impact diffusion according to Fick’s law?
Proportional to: Surface Area Partial pressure difference Solubility of the gas and molecular weight Small thickness of tissue
In the capillaries, O2 uptake depends on diffusion or blood flow?
Blood flow
In the capillaries, CO uptake depends on diffusion or blood flow?
Diffusion
We can measure for some disease with CO diffusing capacities (DLCO). High DLCO can be indicative of what?
Increased pulmonary capillary blood volume
Pulmonary hemorrhage
Polycythemia
Asthma
We can measure for some disease with CO diffusing capacities (DLCO). Low DLCO can be indicative of what?
Emphysema
Interstitial lung disease
Pulmonary vascular disease
Anemia
What is hypoxemia? What is hypoxia?
Low PaO2
Hypoxemia is low O2 in arterial blood
Hypoxia is low O2 at the tissue level
What are the causes of hypoxemia (5 elements)?
Decreased PiO2 Hypoventilation V/Q (ventilation/perfusion) mismatch Shunt Diffusion limitation
Does physiological dead space cause hypoxemia?
NO
What is shunt?
Perfusion, but no ventilation
What is dead space?
Ventilation, but no perfusion
What is pulmonary shunt? Give some disease examples.
Extreme form of V/Q mismatch, caused by shunt.
Disease: pulmonary edema, consolidation, atelectasis, airway obstruction
What is extrapulmonary shunting? Give some disease examples.
V/Q mismatch resulting from the blood bypassing the pulmonary circulation altogether.
Disease: ductus arteriosus, heart septal defects, thebesian veins
How can you calculate the physiological dead space?
Using the Bohr method: the more dead space, the more deluded the expired CO2
You find that the patient has hypoxemia, but his (A-a)O2 difference is normal. What could be the causes of hypoxemia?
Hyperventilation
Altitude
You find that the patient has hypoxemia, but his (A-a)O2 difference is increased. Further, the patient is responsive to breathing 100% oxygen. What could be the cause of hypoxemia?
Low V/Q ratio
You find that the patient has hypoxemia, but his (A-a)O2 difference is increased. Further, the patient is not so responsive to breathing 100% oxygen. What could be the causes of hypoxemia?
Shunt
