Pulse Oximeter
History of Pulse Oximetry
Before the Pulse-Oximeter the only way to measure SpO2 was by using a painful arterial blood gas which took a minimum of 20-30 minutes to view the result. In 1974 Takuo Aoyagi a Niigata University student disclosed his first Pulse-Oximeter for the use of pilots in World War 2. He set about searching for a non-invasive way of monitoring arterial blood oxygen saturation. Nellcor’s pulse oximeter was put on the market in 1983 and this used his theory developed in 1974.
By 1987 Pulse Oximetry became part of a standard procedure in administrating anaesthetic. The use of oximetry quickly spread to other hospital units. By 1995 fingertip pulse oximeters were marketed. But unfortunately use of pulse oximetry in developing countries is not widespread.
Even though Pulse-Oximetry came so far problems still occur such as noise rejection (movement) and accurate calibration. These are challenges were encountered in our project.
Principles of Pulse Oximetry
The Pulse Oximeter system consists of the probe that senses the pulse, together with the circuitry required to analyse the measurements. A core part of the pulse oximeter is a measure of how much of the haemoglobin in blood is carrying oxygen (oxygen saturation). As you inhale oxygen enters the lungs and then it gets passed into the blood which is full of haemoglobin. Haemoglobin takes the oxygen to the organs of the human body. Haemoglobin with oxygen is called oxygenated haemoglobin. Haemoglobin without oxygen is called deoxygenated haemoglobin.
One molecule of haemoglobin can carry up to four molecules of oxygen – this is described as oxygen saturation.
Beers law explains how light is absorbed my any physical object.
The equation of Beers Law: A=log10 ().
Where I0 is the intensity of the incident light and I is the transmitted light. This varies according to things such as the distance the light has to travel and physical properties of the object. In Pulse-Oximetry properties would
Before the Pulse-Oximeter the only way to measure SpO2 was by using a painful arterial blood gas which took a minimum of 20-30 minutes to view the result. In 1974 Takuo Aoyagi a Niigata University student disclosed his first Pulse-Oximeter for the use of pilots in World War 2. He set about searching for a non-invasive way of monitoring arterial blood oxygen saturation. Nellcor’s pulse oximeter was put on the market in 1983 and this used his theory developed in 1974.
By 1987 Pulse Oximetry became part of a standard procedure in administrating anaesthetic. The use of oximetry quickly spread to other hospital units. By 1995 fingertip pulse oximeters were marketed. But unfortunately use of pulse oximetry in developing countries is not widespread.
Even though Pulse-Oximetry came so far problems still occur such as noise rejection (movement) and accurate calibration. These are challenges were encountered in our project.
Principles of Pulse Oximetry
The Pulse Oximeter system consists of the probe that senses the pulse, together with the circuitry required to analyse the measurements. A core part of the pulse oximeter is a measure of how much of the haemoglobin in blood is carrying oxygen (oxygen saturation). As you inhale oxygen enters the lungs and then it gets passed into the blood which is full of haemoglobin. Haemoglobin takes the oxygen to the organs of the human body. Haemoglobin with oxygen is called oxygenated haemoglobin. Haemoglobin without oxygen is called deoxygenated haemoglobin.
One molecule of haemoglobin can carry up to four molecules of oxygen – this is described as oxygen saturation.
Beers law explains how light is absorbed my any physical object.
The equation of Beers Law: A=log10 ().
Where I0 is the intensity of the incident light and I is the transmitted light. This varies according to things such as the distance the light has to travel and physical properties of the object. In Pulse-Oximetry properties would