Mostly for when constant, non-invasive monitering is required, such as during surgery for a patient under anaesthetics (so you know if they suddenly stop breathing, etc)
we used one yesterday at uni to monitor a patient's SpO2% during exercise testing. if her % went below 85 we were meant to stop the test.
very non-invasive- you can put it on your finger while you're walking and keep doing the test.
its used for almost a whole lot more than just "emergency types".. u use it on alot of ppl... like on the cardiac and resp wards.. even if they are kinda minor.. cos its just so uninvasive
a lil extra curricular information:
samtam: in anaesthetics.. they use respiratory volumes to measure breathing so a reading called FEV, tidal volumes and FVC.. the pulse oximetry is for oxygen saturation (SpO2).. cos there is a massive lag time.. between u stop breathing and ure saturation going..
its analogous to ure car... u dun refuel when it starts to slow down and the fuel injection is sounds lik its spitting.. u rather refuel when the fuel guage is about to hit empty..
it measures oxygen saturation and carbon dioxide concentrations in blood. a peg is attached to the finger of the patient where a light is transmited through to the other side of the finger. a photo detector on the other side measures how much light has been transmitted through. the amount is directly proportional to the amount of oxygen in arterial blood.