An increase in which of the following parameters will shift the O2 dissociation curve to the left -
Hb-O2 dissociation curve shift to left indicates more affinity of Hb to O2 and thus less delivery of O2 to tissues.
Shift to left seen in
-        Increased pH
-        Decreased 2,3 DPG, temperature, PCO2
-        HbF (Fetal)
Shift to right seen in
-        Decreased pH
-        Increased 2,3DPG, temperature, PCO2
-        HbS (Sickle cell)
Increased temperature
Increased partial pressure of CO2
Increased 2, 3 DPG concentration
Increased oxygen affinity of hemoglobin