Oxy-Hgb Dissociation Curve

Oxygen-Hemoglobin Dissociation Curve - Summary

The percentage of saturated hemoglobin vs the partial pressure of oxygen, determined by oxygen affinity. Affected by: pH, pCO2, 2-3 DPG, temperature

Oxy-Hgb Axis

Vertical: % saturated hemoglobin

Horizontal: pO2 (mmHg)

Positive Cooperativity

Each O2 molecule bound to Hgb increases Hgb’s affinity for O2

P50

The partial pressure of O2 where 50% of Hgb is saturated

A left shift causes a ___ in p50

decreased

A right shift causes a ___ p50

increased

Oxy-Hgb Dissociation Curve Overview

pH change will be the same as O2 affinity (increased pH = increased O2 affinity)

All other factors will be opposite (pCO2; 2,3-DPG; temperature)

Increased pCO2 causes a ___ shift

Right

Decreased pCO2 causes a ___ shift

Left

Increased pH causes a ___ shift

Left

Decreased pH causes a ___ shift

Right

Increased temperature causes a ___ shift

Right

Decreased temperature causes a ___ shift

Left

Increased 2,3-DPG causes a ___ shift

Right

Decreased 2,3-DPG causes a ___ shift

Left

Fetal hemoglobin has a ___ shift compared to maternal hemoglobin

Left

Carbon monoxide causes what to happen to the Oxy-Hgb curve?

Causes a left shift and flattens curve at the % O2 saturation

CO has a 250x ___ affinity for o2

Higher