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Towards Investigating Global Warming Impact on Human Health Using Derivatives of Photoplethysmogram Signals.

Elgendi M, Norton I, Brearley M, Fletcher RR, Abbott D, Lovell NH, Schuurmans D - Int J Environ Res Public Health (2015)

Bottom Line: However, analyzing the PPG wave contour is difficult; therefore, researchers have applied first or higher order derivatives to emphasize and conveniently quantify subtle changes in the filtered PPG contour.The results of our study indicate that the use Int.Environ.

View Article: PubMed Central - PubMed

Affiliation: Electrical and Computer Engineering in Medicine Group, University of British Columbia and BC Children's Hospital, Vancouver, BC V6H 3N1, Canada. moe.elgendi@gmail.com.

ABSTRACT
Recent clinical studies show that the contour of the photoplethysmogram (PPG) wave contains valuable information for characterizing cardiovascular activity. However, analyzing the PPG wave contour is difficult; therefore, researchers have applied first or higher order derivatives to emphasize and conveniently quantify subtle changes in the filtered PPG contour. Our hypothesis is that analyzing the whole PPG recording rather than each PPG wave contour or on a beat-by-beat basis can detect heat-stressed subjects and that, consequently, we will be able to investigate the impact of global warming on human health. Here, we explore the most suitable derivative order for heat stress assessment based on the energy and entropy of the whole PPG recording. The results of our study indicate that the use Int. J. Environ. Res. Public Health 2015, 7 12777 of the entropy of the seventh derivative of the filtered PPG signal shows promising results in detecting heat stress using 20-second recordings, with an overall accuracy of 71.6%. Moreover, the combination of the entropy of the seventh derivative of the filtered PPG signal with the root mean square of successive differences, or RMSSD (a traditional heart rate variability index of heat stress), improved the detection of heat stress to 88.9% accuracy.

No MeSH data available.


Related in: MedlinePlus

Measurement protocol. The duration of the whole experiment was approximately 4 h; each exercise consumed approximately 30 min, while the photoplethysmogram (PPG) signals were collected during the 30-minute break of each exercise.
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ijerph-12-12776-f001: Measurement protocol. The duration of the whole experiment was approximately 4 h; each exercise consumed approximately 30 min, while the photoplethysmogram (PPG) signals were collected during the 30-minute break of each exercise.

Mentions: The heat stress PPG data for this study were collected as part of a National Critical Care and Trauma Response Centre (NCCTRC) project to assess the physiological and perceptual responses of emergency responders to simulated chemical, biological and radiological (CBR) incidents in tropical environmental conditions to compare the efficacy of various cooling methods. The background of the NCCTRC’s thermal research can be found in [30]. Forty healthy, heat-acclimatized emergency responders (30 males and 10 females) with a median ± interquartile range age of 34.0 ± 9.0 years volunteered and provided written informed consent to participate in this study, which was approved by the Human Research Ethics Committee of the Northern Territory Department of Health and the Menzies School of Health Research. Participants undertook 30 min of triaging and resuscitating, transporting and decontaminating weighted manikins while wearing Level 3 personal protective equipment, which comprises a fully-enclosed, impermeable suit that includes boots, gloves, hood, face mask and respirator (SE400i, S.E.A. Group, Warriewood, Australia), followed by 30 min of rest and cooling to avoid overheating during the exercise. This protocol was repeated three times with PPG data collected during each rest period, as shown in Figure 1. Here, PPG data were measured using a photoplethysmography-equipped device (Salus APG, Japan) at a sampling rate of 367 Hz, with the sensor located at the cuticle of the second digit of the left hand. Measurements were taken for 20 s while participants were resting in a seated position. Note that monitoring PPG during exercise was not possible due to the personal protective equipment (gloves) required to perform physical tasks.


Towards Investigating Global Warming Impact on Human Health Using Derivatives of Photoplethysmogram Signals.

Elgendi M, Norton I, Brearley M, Fletcher RR, Abbott D, Lovell NH, Schuurmans D - Int J Environ Res Public Health (2015)

Measurement protocol. The duration of the whole experiment was approximately 4 h; each exercise consumed approximately 30 min, while the photoplethysmogram (PPG) signals were collected during the 30-minute break of each exercise.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4626999&req=5

ijerph-12-12776-f001: Measurement protocol. The duration of the whole experiment was approximately 4 h; each exercise consumed approximately 30 min, while the photoplethysmogram (PPG) signals were collected during the 30-minute break of each exercise.
Mentions: The heat stress PPG data for this study were collected as part of a National Critical Care and Trauma Response Centre (NCCTRC) project to assess the physiological and perceptual responses of emergency responders to simulated chemical, biological and radiological (CBR) incidents in tropical environmental conditions to compare the efficacy of various cooling methods. The background of the NCCTRC’s thermal research can be found in [30]. Forty healthy, heat-acclimatized emergency responders (30 males and 10 females) with a median ± interquartile range age of 34.0 ± 9.0 years volunteered and provided written informed consent to participate in this study, which was approved by the Human Research Ethics Committee of the Northern Territory Department of Health and the Menzies School of Health Research. Participants undertook 30 min of triaging and resuscitating, transporting and decontaminating weighted manikins while wearing Level 3 personal protective equipment, which comprises a fully-enclosed, impermeable suit that includes boots, gloves, hood, face mask and respirator (SE400i, S.E.A. Group, Warriewood, Australia), followed by 30 min of rest and cooling to avoid overheating during the exercise. This protocol was repeated three times with PPG data collected during each rest period, as shown in Figure 1. Here, PPG data were measured using a photoplethysmography-equipped device (Salus APG, Japan) at a sampling rate of 367 Hz, with the sensor located at the cuticle of the second digit of the left hand. Measurements were taken for 20 s while participants were resting in a seated position. Note that monitoring PPG during exercise was not possible due to the personal protective equipment (gloves) required to perform physical tasks.

Bottom Line: However, analyzing the PPG wave contour is difficult; therefore, researchers have applied first or higher order derivatives to emphasize and conveniently quantify subtle changes in the filtered PPG contour.The results of our study indicate that the use Int.Environ.

View Article: PubMed Central - PubMed

Affiliation: Electrical and Computer Engineering in Medicine Group, University of British Columbia and BC Children's Hospital, Vancouver, BC V6H 3N1, Canada. moe.elgendi@gmail.com.

ABSTRACT
Recent clinical studies show that the contour of the photoplethysmogram (PPG) wave contains valuable information for characterizing cardiovascular activity. However, analyzing the PPG wave contour is difficult; therefore, researchers have applied first or higher order derivatives to emphasize and conveniently quantify subtle changes in the filtered PPG contour. Our hypothesis is that analyzing the whole PPG recording rather than each PPG wave contour or on a beat-by-beat basis can detect heat-stressed subjects and that, consequently, we will be able to investigate the impact of global warming on human health. Here, we explore the most suitable derivative order for heat stress assessment based on the energy and entropy of the whole PPG recording. The results of our study indicate that the use Int. J. Environ. Res. Public Health 2015, 7 12777 of the entropy of the seventh derivative of the filtered PPG signal shows promising results in detecting heat stress using 20-second recordings, with an overall accuracy of 71.6%. Moreover, the combination of the entropy of the seventh derivative of the filtered PPG signal with the root mean square of successive differences, or RMSSD (a traditional heart rate variability index of heat stress), improved the detection of heat stress to 88.9% accuracy.

No MeSH data available.


Related in: MedlinePlus