A number which will be closely monitored in a hospital situation is the oxygen saturation level which is a number that represents the amount of hemoglobin being transported in the bloodstream. There are machines at the hospital which act as pulse oximeters and also machines that can be used for this purpose at home and generally a level of 95 to 100% saturation is preferred in the bodies of children and adults. For premature babies this number is usually lower and may be around 88% because any higher saturation could lead to dangerous complications like retinopathy of prematurity.