Hello Dear!! Quadruple heart surgery is a very serious and lengthy procedures and a patient loose a-lot of blood . loosing this much blood make you pale. so I suggest you to do Full Blood Count/Hb. This test will tell us if there is blood deficiency.. So if their is defiency the treatment is very simple 1) medication which include Iron and Folic acids 2) Blood transfusion. we will decide between these two depending upon the above test. If above test show us severe deficiency then blood transfuion is the answer other wise iron/folic acid supplements are enough.