The study quantified functional measures of red blood cell mass and oxygen in neonatal tissues using a non-invasive optical technique: near infrared optical spectroscopy . The study will determine the absolute concentrations of deoxygenated and oxygenated hemoglobin and calculate the tissue hemoglobin saturation and total hemoglobin concentration in viv. Near infrared optical spectroscopy technique use to assessing and defining tissue status in the anemic state and the tissue's response to transfusions, as well as in monitoring hemoglobin and hematocrit without pain or loss of blood.