Pulse oximetry
Pulse oximetry is a tool which non-invasively measures arterial oxyhemoglobin (ch.4) giving a percentage value for oxygen saturation (sao2). Their relative inaccuracy of theses machines (I.e. Their unreliability in reflecting arterial oxygenation) means that they connot be used as the only method of monitoring trends of change in arterial oxygenation in acutely ill infants and children.