The pulse oximeter, also known as a pulse oximeter or SpO2 monitor, has the function of measuring heart rate and oxygen saturation in the blood.
There is a wide range of choices of oximeters intended for healthcare professionals and individuals alike for self-measurement to monitor, for example, the effectiveness of a treatment for respiratory ailments.
And we distinguish the portable pulse oximeter whose sensor is deported and exchangeable, from the finger pulse oximeter whose sensor is integrated into the device which makes it compact and ideal for mobile use. Here the Omron Nissei pulse oximeter buy comes with the smartest deductions that makes the treatments come really quick.
The Criteria To Observe Before Choosing:
- For a healthcare professional or an individual?
- The size, the diameter of the sensor: is it for an infant an adult ?
- Shock resistance
- Automatic On / Off, to save batteries
- Automatic swivel screen… and backlit: for easy reading
- Also indicates the SpO2 curve
- In color? Convenient to spot it in emergency room bags or to differentiate it between departments
The pulse oximeter (or saturometer) makes it possible to measure in a simple, reliable, non-invasive and continuous way the arterial saturation of hemoglobin.
Sa O2 = Hb O2 / total Hb
The value given by the pulse oximeter is called “Pulsed hemoglobin oxygen saturation”, or SpO2, to distinguish it from arterial hemoglobin O2 saturation, measured by blood gases (SaO2).
Presentation of the material
The device is made up of two parts:
- the monitor, which is an independent box or integrated into another device, allows the measurement and its alarm limits to be adjusted and displays the plethysmography curve (pulsatile wave);
- the sensor, which most often takes the form of a clamp or finger cot.
There are other models, intended to be placed on the nose, earlobe, hand. The sensors can be disposable or reusable.
The sensor contains two diodes emitting a red light which must be located in front of an easily identifiable receiving area.
The best results are obtained by placing the transmitter on the nail (mnemonic: ruby on the nail). The screen includes the display of the measured parameters (saturation and frequency of pulses) and a curve. The displayed value is only reliable if the curve is clearly legible.
Principle of measurement
The principle is based on the emission of two lights (red and infrared), respectively 660 and 940 nm, and the measurement of their absorption by the pulsatile flow. The absorption of red and infrared light will vary depending on whether it encounters non-oxygenated reduced hemoglobin (Hb) or oxyhemoglobin (HbO2). The pulse oximeter calculates the saturation of the pulsatile flow, eliminating the values corresponding to venous and capillary blood. The result is very well correlated with arterial saturation measured by blood gas (SaO2).
Limits of the measurement
Limits related to the need to perceive a pulsatile signal
The pulse oximeter does not work in the event of circulatory arrest or patient under cardiac circulation (CEC: continuous flow, no pulsatile flow). It works poorly or not at all in all situations where the blood circulates poorly where the sensor is placed: arterial hypotension, low blood flow, vasoconstriction (hypothermia, use of vasoconstrictors). If you place a blood pressure cuff on the same arm as the sensor, the pulse oximeter does not work during measurement.
