Which of the following statement (s) is/are true about Hb–O2 dissociation curvea) Fetal Hb shifts curve to leftb) Hypothermia shifts curve to leftc) Hypercarbia shifts curve to leftd) Left shift cause more O2 release to tissue: (A) ab, (B) a, (C) ad, (D) bc
Answer is A. 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)