Basics
The curve is a representation of the relationship of what 2 things?
Hb saturation and PO2
The curve is the shape of which letter?
S
A right shift means oxygen will unload easier from hemoglobin. True or False.
True
A patient with Chronic Obstructive Pulmonary Disease (COPD) often has chronically high levels of CO2 (hypercapnia). How does their body typically shift the curve to compensate?
Rigt shift--> high CO2 and resulting acidity aid in oxygen unloading
What is hemoglobin?
This protein, found in red blood cells, is responsible for binding and transporting oxygen throughout the body.
This is the unit of pressure typically used for the X-axis (PO2), representing the "force" of oxygen in the blood.
mmHg
Decreased CO2, increased pH, decreased 2,3 DPG, and decreased temperature will do what to the curve?
Left shift
A patient is suffering from severe Diabetic Ketoacidosis (DKA), resulting in a very low blood pH. What is the expected effect on their oxygen-hemoglobin curve?
Right shift
As more oxygen is bound to hemoglobin it has less of an affinity to bind more. True or False.
False
On a normal curve, with a PaO2 of 50 mm Hg, what percent of hemoglobin would we expect to be saturated?
85%
This effect describes how an increase in blood CO2 and a decrease in pH cause the curve to shift to the right, promoting oxygen unloading in metabolically active tissues.
Bohr effect
Septic shock often causes a localized buildup of lactic acid in the tissues. How does this affect the P50 in those areas?
Lactic acid lowers pH, increasing P50 and facilitates unloading of oxygen where it is needed most
The term utilization co-efficient refers to?
% of blood that gives up its O2 as it passes through tissue
At the summit of Mt. Everest, the body operates on this specific part of the curve, where even a tiny move is life-threatening.
Steep Portion
A patient has a P50 value (the partial pressure of at which 50% of hemoglobin is saturated) of 35 mmHg. What does this indicate compared to the normal P50 of 27 mmHg?
D. Decreased affinity; right shift
This term describes the phenomenon where the curve’s shape remains sigmoidal but the total oxygen content drops because of a low red blood cell count.
Anemia
This specific point on the curve represents the partial pressure of oxygen at which hemoglobin is 50% saturated.
Unlike the sigmoidal curve of hemoglobin, this single-unit muscle protein has a hyperbolic curve because it lacks cooperativity.
Myoglobin
Poisoning by this gas causes a dangerous left shift and changes the curve's shape, effectively "locking" oxygen onto hemoglobin so it can't be released.
Carbon Monoxide
This is the specific reason why a pulse oximeter might show a "normal" 99% saturation even if a patient is dying of Carbon Monoxide poisoning.
Competitive Binding (or the device can't distinguish between $O_2$ and $CO$