Oxygen is carried round the body in the blood bound to a substance called haemoglobin and the simplest way to measure how much oxygen is in your blood is by using a pulse oximeter.
A pulse oximeter is a little gadget that clips on your finger like a clothes peg. It shines two lights though your fingertip and measures the colour difference between oxygenated and deoxygenated haemoglobin in arterial blood, displaying the result as a percentage. Under normal conditions this should be between 97- 99% symbolised as SP02 You can see details of our PO 30 HERE
So why might you need to monitor your oxygen level?
For most people with a chest condition, shortness of breath becomes part and parcel of your lifestyle to some degree or other. In mild cases it may only be present during the winter or after a cold. In more severe cases, you may be short of breath every day and because of breathlessness normal activities can become more difficult, some of you may even need extra oxygen at home. A home pulse oximeter can be used as an extra tool to assist you in monitoring your symptoms.
So what are some of its limitations?
High levels of artificial light and dirt under your nails or nail varnish may affect the reading. The oximeter needs to read at least 5 fingertip pulse beats and therefore should not be read in an instant. Movement, such as shaking or shivering can affect the reading as can and pre existing medical conditions such as anaemia, heart or circulation problems. As it only measures one aspect of the process haemoglobin oxygen delivery and not all you could have normal saturation levels and still be short of oxygen in your body tissue.
“Pulse oximetry is considered sufficiently accurate for most clinical purposes having recognised its limitations.” Howell M (2002) The Correct Use of Pulse Oximetry in measuring oxygen status Nursing Times.net.
It also monitors your fingertip pulse rate and for adults and adolescents when resting an average pulse is between 60-100 beats per minute but for those of you with a pre existing medical condition it can vary. It doesn’t monitor your pulses rhythm or strength and needs to be judged over a short period of time. So before you panic, remember pulse oximetry has limitations and has to be considered in context. Were you resting or had you only just sat down? Are your fingers extra cold today? Does using a pulse oximeter make you feel anxious? All factors which can affect your results.
Always remember to take into account other signs and symptoms that have helped you in the past. How do you feel? Are you unwell? Has your breathing become quicker or more shallow? What is your peak flow? Is your heart racing? Whatever the display on the pulse oximeter shows if you are concerned at all always seek medical help
For an expert patient a pulse oximeter can be a valuable additional tool so why not take a look by clicking HERE and choose which one would suit you.
I am always concerned by people wanting a pulse Oxymeter because often by the oxygen levels have dropped in an asthmatic they can be extremly ill. As you say, people must take into account all other signs.
ReplyDeleteI am brittle asthmatic, have O2 at home but don't have a pulse oxymeter - I go on how I feel. This is OK most of the time but a few weeks ago, I was so tired that I was unaware how ill I was - My paramedic friend popped one on my finger - low 80s! He blue lighted me in! Often I don't drop my sats until the last minute.
Kate