Red blood cell are cells present in blood in order to transport oxygen. The only known vertebrates without red blood cells are the crocodile icefish (family Channichthyidae); they live in very oxygen-rich cold water and transport oxygen freely dissolved in their blood. While they no longer use hemoglobin, remnants of hemoglobin genes can be found in their genome. Vertebrate red blood cells consist mainly of hemoglobin, a complex metalloprotein containing heme groups whose iron atoms temporarily bind to oxygen molecules (O) in the lungs or gills and release them throughout the body. Oxygen can easily diffuse through the red blood cell's cell membrane.
Neonatal red cell transfusion Neonatal red cell transfusion Neonates are defined as babies up to 28 days after birth. Most extremely preterm babies (less than 28 weeks) require at least one red cell transfusion, this is partly due to the amount of blood removed with blood samples compared to the baby's total blood volume (iatrogenic anemia) and partly due to anemia of prematurity. Most transfusions are given as small volume top-up transfusions to increase the baby's hemoglobin above a certain pre-defined level, or because the baby is unwell due to the anemia. Possible side-effects of anemia in babies can be poor growth, lethargy and