A photoelectric plethysmograph for the measurement of cutaneous blood flow

Challoner, A. V. J.; Ramsay, Colin A.

doi:10.1088/0031-9155/19/3/003

Cited by 193 publications

(175 citation statements)

References 12 publications

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“…Photoplethsymography relates changes in intensity to changes in blood volume (pulsatile) in the sample tissue (Challoner 1979). Both transmissive and reflective modes of operation are possible.…”

Section: Assessing the Affects Of Pressure On The Microcirculationmentioning

confidence: 99%

An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot

Cobb¹,

Claremont²

2001

Medical Engineering & Physics

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An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot. Jonathan Edwin CobbPlantar ulceration is a complication of the diabetic foot prevalent in adults with type 11 diabetes mellitus. Although neuropathy, microvascular disease and biornechanical factors are all implicated, the mechanism by which the tissue becomes pre-disposed to damage remains unclear. Recent theories suggest that the nutritional supply to the tissue is compromised, either by increased flow through the arteriovenous anastomoses ('capillary steal' theory) or through changes in the micro vascu I ature (haemodynamic hypothesis). Clinical data to support these ideas has been limited to assessment of the unclad foot under rest conditions. A limitation of previous studies has been the exclusion of static and dynamic tissue loading, despite extensive evidence that these biornechanical factors are essential in the development of plantar ulceration. The present study has overcome these problems by allowing assessment of plantar blood flow, in-shoe, during standing and walking.The system comprises a laser Doppler blood flux sensor operating at 780nm, load sensor, measurement shoe, instrumentation, and analysis software. In-vitro calibration was performed using standard techniques. An in-vivo study of a small group of diabetic subjects indicated differences in the blood flux response between diabetic neuropaths, diabetics with vascular complications and a control group. For example, following a loading period of 120s, relative increases in response from rest to peak were: Control (150% to 259%), Vascular (-70% to 242%), Neuropathic (109%-174%) and recovery times to 50% of the peak response were: Control (33s to 45s), Vascular (43s to >120s), Neuropathic (>120s). Dynamic re-perfusion rates (arbitrary units per millisecond) obtained for the swing phase of gait were: Control (6.1 a. u/ms to 7.9 a. u/ms), Vascular (4 a. u/ms to 6.2 a. u/ms), Neuropathic (2.3 a. u/ms to 4.5 a. u/ms).

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Section: Assessing the Affects Of Pressure On The Microcirculationmentioning

confidence: 99%

An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot

Cobb¹,

Claremont²

2001

Medical Engineering & Physics

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“…Photoplethysmography (PPG) is a popular optical technology for the monitoring heart rate (HR) in normal daily life due to its simplicity and convenience, in its simplest form only requiring the attachment of a light emitting diode (LED) and a photodetector (PD) [1,2]. However, the reliability of PPG signals measured during normal daily life can be reduced by motion artifacts [3,4].…”

Section: Introductionmentioning

confidence: 99%

Comparison between red, green and blue light reflection photoplethysmography for heart rate monitoring during motion

Lee

Matsumura

Yamakoshi

et al. 2013

2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

103

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Abstract-Reflection photoplethysmography (PPG) using 530 nm (green) wavelength light has the potential to be a superior method for monitoring heart rate (HR) during normal daily life due to its relative freedom from artifacts. However, little is known about the accuracy of pulse rate (PR) measured by 530 nm light PPG during motion. Therefore, we compared the HR measured by electrocadiography (ECG) as a reference with PR measured by 530, 645 (red), and 470 nm (blue) wavelength light PPG during baseline and while performing hand waving in 12 participants. In addition, we examined the change of signal-to-noise ratio (SNR) by motion for each of the three wavelengths used for the PPG. The results showed that the limit of agreement in Bland-Altman plots between the HR measured by ECG and PR measured by 530 nm light PPG (±0.61 bpm) was smaller than that achieved when using 645 and 470 nm light PPG (±3.20 bpm and ±2.23 bpm, respectively). The ΔSNR (the difference between baseline and task values) of 530 and 470nm light PPG was significantly smaller than ΔSNR for red light PPG. In conclusion, 530 nm light PPG could be a more suitable method than 645 and 470nm light PPG for monitoring HR in normal daily life. I. INTRODUCTIONPhotoplethysmography (PPG) is a popular optical technology for the monitoring heart rate (HR) in normal daily life due to its simplicity and convenience, in its simplest form only requiring the attachment of a light emitting diode (LED) and a photodetector (PD) [1,2]. However, the reliability of PPG signals measured during normal daily life can be reduced by motion artifacts [3,4]. Thus, various techniques for the Jihyoung Lee is with Graduate

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“…11,12 One common technique, using simple low-cost optical technology, is photoplethysmography (PPG). [13][14][15][16] The output of the infrared PPG transducer is proportional to changes in the volume of red blood cells in the peripheral micro-vascular bed, these changes being associated with each heart beat. PPG pulse signals can easily be obtained from the tissue pads of the ears, fingers and toes where there is a high degree of superficial vasculature.…”

Section: Introductionmentioning

confidence: 99%

Age-related changes in peripheral pulse timing characteristics at the ears, fingers and toes

2002

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It is accepted that older subjects have increasing arterial stiffness, which results in increasingly faster pulse transmission to the periphery. However, this age association is less clear in younger subjects and for different peripheral measurement sites. The aims of this study were to determine the association between age and pulse timing characteristics over a five decade age range at the ears, fingers and toes, and to compare these with any additional effects associated with differences in subject height, systolic blood pressure and heart rate. Photoplethysmography pulse waveforms were recorded noninvasively from the right and left sides at the ears, fingers and toes of 116 normal healthy human subjects. Their median age was 42 years (range 13-72 years). Systolic blood pressure, height and heart rate were also measured. Pulse transit times (PTTs) were determined and referenced to the electrocardiogram R wave. The results revealed that age was the strongest contributor to PTT differences at all sites (Po0.0001). The decrease with ageing was greatest at the toes: À1.6, À0.6, À0.4 ms/year for the toes, fingers, and ears, respectively. Changes for the right and left body sides at each level were highly similar. Blood pressure was also an important contributor to PTT at all sites (Po0.0001); À1.0, À0.4, À0.3 ms/ mm Hg, respectively, with approximately half of the effect explained by age. Height was significantly and independently related to PTT at the fingers and toes (Po0.0001); +1.1, +0.7 ms/cm, respectively. The fraction of PTT variability explained by these relationships was 0.65, 0.48, 0.26 for the toes, fingers and ears, respectively (Po0.0001). Finally, we concluded that the age effect decreased linearly from the second to the seventh decades, demonstrating that the effect of changes in arterial stiffness can be detected noninvasively from an early age at three main peripheral sites. Age is the dominant factor in contributing to PTT, and is greatest at the toes, followed by the fingers and then the ears.

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A photoelectric plethysmograph for the measurement of cutaneous blood flow

Cited by 193 publications

References 12 publications

An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot

An in-shoe laser Doppler sensor for assessing plantar blood flow in the diabetic foot

Comparison between red, green and blue light reflection photoplethysmography for heart rate monitoring during motion

Age-related changes in peripheral pulse timing characteristics at the ears, fingers and toes

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