The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry
Since the early 1980s the increase in use of pulse oximeters in many clinical situations has been quite remarkable, turning it into one of the most important methods of monitoring in use today. Pulse oximetry essentially uses photoplethysmography to calculate oxygen saturation. Consequently the wave...
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| Format: | Thesis (University of Nottingham only) |
| Language: | English |
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1995
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| Online Access: | https://eprints.nottingham.ac.uk/11400/ |
| _version_ | 1848791268270800896 |
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| author | Damianou., Damianos. |
| author_facet | Damianou., Damianos. |
| author_sort | Damianou., Damianos. |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Since the early 1980s the increase in use of pulse oximeters in many clinical situations has been quite remarkable, turning it into one of the most important methods of monitoring in use today. Pulse oximetry essentially uses photoplethysmography to calculate oxygen saturation. Consequently the wavelength dependence of the photoplethysmogram (PPG) is of direct relevance in the performance of pulse oximeters.
The experimental results obtained on the wavelength dependence of the AC, DC and AC/DC PPG components for the 450 - 1000nm range are undoubtedly different to the ones predicted by the current simple pulse oximeter model based on the Lambert-Beer law. Moreover, they show unexpected phenomena regarding the magnitude of the above components over the whole range, with distinct differences between the reflection and transmission modes. This is of significance to the technique of pulse oximetry suggesting that perhaps other wavelengths should be considered for use, and that use of both "reflection" and "transmission" probes on the same oximeter may lead to inaccurate readings in one of the modes.
A finger model was developed and results from Monte Carlo simulations of photon propagation obtained. The results did not correspond to the experimental results, this is most probably due to either wrong parameters or model.
Recent advances in the use of reflection pulse oximeters on fetal monitoring during labour, have raised the question of possible artifacts which may arise due to inadequate probe application in the birth canal. The importance of complete opposition of the reflectance probe was examined on an adult finger. False low oxygen saturation readings were recorded with malpositioned probes. A new probe with modified geometry was designed which offered an improved performance in reducing this artifact and further suggestions were given for its possible elimination.
Finally, a proposal for a novel, visible multi-wavelength reflection pulse oximeter is presented with the aim of replacing current pulse oximeters in certain situations where their use is questionable. |
| first_indexed | 2025-11-14T18:25:48Z |
| format | Thesis (University of Nottingham only) |
| id | nottingham-11400 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T18:25:48Z |
| publishDate | 1995 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-114002025-02-28T11:13:10Z https://eprints.nottingham.ac.uk/11400/ The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry Damianou., Damianos. Since the early 1980s the increase in use of pulse oximeters in many clinical situations has been quite remarkable, turning it into one of the most important methods of monitoring in use today. Pulse oximetry essentially uses photoplethysmography to calculate oxygen saturation. Consequently the wavelength dependence of the photoplethysmogram (PPG) is of direct relevance in the performance of pulse oximeters. The experimental results obtained on the wavelength dependence of the AC, DC and AC/DC PPG components for the 450 - 1000nm range are undoubtedly different to the ones predicted by the current simple pulse oximeter model based on the Lambert-Beer law. Moreover, they show unexpected phenomena regarding the magnitude of the above components over the whole range, with distinct differences between the reflection and transmission modes. This is of significance to the technique of pulse oximetry suggesting that perhaps other wavelengths should be considered for use, and that use of both "reflection" and "transmission" probes on the same oximeter may lead to inaccurate readings in one of the modes. A finger model was developed and results from Monte Carlo simulations of photon propagation obtained. The results did not correspond to the experimental results, this is most probably due to either wrong parameters or model. Recent advances in the use of reflection pulse oximeters on fetal monitoring during labour, have raised the question of possible artifacts which may arise due to inadequate probe application in the birth canal. The importance of complete opposition of the reflectance probe was examined on an adult finger. False low oxygen saturation readings were recorded with malpositioned probes. A new probe with modified geometry was designed which offered an improved performance in reducing this artifact and further suggestions were given for its possible elimination. Finally, a proposal for a novel, visible multi-wavelength reflection pulse oximeter is presented with the aim of replacing current pulse oximeters in certain situations where their use is questionable. 1995 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/11400/1/309547.pdf Damianou., Damianos. (1995) The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry. PhD thesis, University of Nottingham. Pulse oximeters anoxemia fetal monitoring |
| spellingShingle | Pulse oximeters anoxemia fetal monitoring Damianou., Damianos. The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry |
| title | The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry |
| title_full | The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry |
| title_fullStr | The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry |
| title_full_unstemmed | The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry |
| title_short | The wavelength dependence of the photoplethysmogram and its implication to pulse oximetry |
| title_sort | wavelength dependence of the photoplethysmogram and its implication to pulse oximetry |
| topic | Pulse oximeters anoxemia fetal monitoring |
| url | https://eprints.nottingham.ac.uk/11400/ |