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Larsen, Peter; Harty, Murray; Thiruchelvam, Mohana; Galletly, D. C.

doi:10.1023/a:1016942504084

Cited by 27 publications

(13 citation statements)

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“…Vasoconstriction in a heat-loss effector organ is a typical thermoregulatory response mediated by the sympathetic nervous system during endotoxin challenge (Blessing 2004, Ohashi and Saigusa 1997, Saigusa 1990). Similar to the toe PPGV, the rise in ear PPGV LF and MF powers coincided with the occurrence of ear vasoconstriction, which again confirmed the link between sympathetic vasomotor activity and spontaneous slow waves in PPGV (Bernardi et al 1996, Larsen et al 1997, Nitzan et al 1998, Middleton et al 2008, Tang et al 2010, Javed et al 2010. It is noteworthy that the LF and MF powers in PPGV were actually augmented during the occurrence of vasoconstriction, but not after the vasoconstriction became sustained, meaning that the PPGV spectral powers might be a better indicator of the dynamic change in sympathetic tone, rather than its mean level.…”

Section: Discussionsupporting

confidence: 63%

“…The average response curves showed that this sudden rise in spectral powers coincided with a fall in toe pulse amplitude, indicating peripheral vasoconstriction (Allen 2007, Avolio 2002, and the transient rise and fall pattern mirrored the change in SBP and DBP. Concurrent changes in the BP and toe PPG signals are best explained by a sudden surge in sympathetic vasoconstrictor drive prior to endotoxic shock, as non-respiratory slow waves in PPGV have been associated with peripheral sympathetic vasomotor activities (Bernardi et al 1996, Larsen et al 1997, Nitzan et al 1998, Middleton et al 2008, Tang et al 2010, Javed et al 2010.…”

Section: Discussionmentioning

confidence: 99%

“…An emerging application of PPG is the assessment of blood volume status based on the beat-to-beat fluctuation in the PPG waveform, as numerous studies have found that respiratory variation in PPG pulse amplitude (or peak) in mechanically ventilated patients could identify hypovolaemia and predict the responsiveness of cardiac output to fluid therapy (Middleton and Henry 2000, Shelley 2007, Bendjelid 2008. The analysis of beat-to-beat PPG variability (PPGV) using frequency spectrum techniques reveals that the PPG waveform not only exhibits respiratory variation, but also spontaneous rhythms below the respiratory frequency (Bernardi et al 1996, Larsen et al 1997, Nitzan et al 1998, Middleton et al 2008, Tang et al 2010, Javed et al 2010. Similar low frequency waves are found in heart rate and blood pressure variability, which have been attributed to autonomic and various other cardiovascular regulatory mechanisms (Malliani et al 1991, Parati et al 1995, 2006.…”

Section: Introductionmentioning

confidence: 99%

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Augmented photoplethysmographic low frequency waves at the onset of endotoxic shock in rabbits

Grace¹,

Hing²,

Middleton³

et al. 2010

Physiol. Meas.

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A rabbit model of endotoxaemia was employed to study the regional changes in photoplethysmogram (PPG) waveform and its low frequency fluctuations, and how they are related to the physiological events during the time course of endotoxic shock. Endotoxin (1 mg kg(-1) lipopolysaccharide) was injected into eight anaesthetized and mechanically ventilated rabbits. The 90 min monitoring period was divided into six stages, with the onset of hypotension separating the first three (EDTX1-3) and last three (HYPO1-3) stages. The most significant finding was a substantial but transient elevation in sympathetic-related toe PPG variability (PPGV) spectral power in EDTX3 and HYPO1 (P < 0.01 versus EDTX1). The group average response showed that the rapid rise started 15 min before and peaked at the onset of hypotension, which indicated a surge in sympathetic vasomotor activity that preceded the decompensatory blood pressure fall. Ear skin vasoconstriction was evident by a marked and sustained fall in ear PPG amplitude along with a decrease in ear skin temperature at the onset of hypotension, during which the sympathetic-related ear PPGV spectral power was elevated (P < 0.01, HYPO1 versus EDTX1). The results demonstrate the value of PPGV in characterizing regional vascular control and provide important insights into the physiological mechanisms of endotoxic shock.

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Section: Discussionsupporting

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Augmented photoplethysmographic low frequency waves at the onset of endotoxic shock in rabbits

Grace¹,

Hing²,

Middleton³

et al. 2010

Physiol. Meas.

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“…Respiration-induced change is one of representative factors that can change IBIs. Respiration could change the intra-thoracic pressure, thus causing blood flow variations in the venous circulation [21] as well as in the arterial system [22]. For example, inspiration can decrease the intra-thoracic pressure, thus reducing the left ventricular stroke volume as well as the pressure and cross-section of the thoracic aorta [23].…”

Section: Discussionmentioning

confidence: 99%

Ambient temperature effect on pulse rate variability as an alternative to heart rate variability in young adult

Shin

2015

J Clin Monit Comput

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Pulse rate variability (PRV) is a promising physiological and analytic technique used as a substitute for heart rate variability (HRV). PRV is measured by pulse wave from various devices including mobile and wearable devices but HRV is only measured by an electrocardiogram (ECG). The purpose of this study was to evaluate PRV and HRV at various ambient temperatures and elaborate on the interchangeability of PRV and HRV. Twenty-eight healthy young subjects were enrolled in the experiment. We prepared temperature-controlled rooms and recorded the ECG and photoplethysmography (PPG) under temperature-controlled, constant humidity conditions. The rooms were kept at 17, 25, and 38 °C as low, moderate, and high ambient temperature environments, respectively. HRV and PRV were derived from the synchronized ECG and PPG measures and they were studied in time and frequency domain analysis for PRV/HRV ratio and pulse transit time (PTT). Similarity and differences between HRV and PRV were determined by a statistical analysis. PRV/HRV ratio analysis revealed that there was a significant difference between HRV and PRV for a given ambient temperature; this was with short-term variability measures such as SDNN SDSD or RMSSD, and HF-based variables including HF, LF/HF and normalized HF. In our analysis the absolute value of PTT was not significantly influenced by temperature. Standard deviation of PTT, however, showed significant difference not only between low and moderate temperatures but also between low and high temperatures. Our results suggest that ambient temperature induces a significant difference in PRV compared to HRV and that the difference becomes greater at a higher ambient temperature.

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“…The sympathetic control of peripheral vasculature may be monitored by analysing the variability of the finger volume pulse signal measured by the photoplethysmographic (PPG) technique (Bernardi et al 1996, Khanokh et al 2004, Larsen et al 1997, Middleton et al 2008, Nitzan et al 1998. Similar to HRV, the frequency spectrum of finger PPG waveform variability (PPGV) may be divided into LF and HF bands, but the physiologic interpretation of PPGV is different from that of HRV.…”

Section: Introductionmentioning

confidence: 99%

Frequency spectrum analysis of finger photoplethysmographic waveform variability during haemodialysis

et al. 2010

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This study investigates the peripheral circulatory and autonomic response to volume withdrawal in haemodialysis based on spectral analysis of photoplethysmographic waveform variability (PPGV). Frequency spectrum analysis was performed on the baseline and pulse amplitude variabilities of the finger infrared photoplethysmographic (PPG) waveform and on heart rate variability extracted from the ECG signal collected from 18 kidney failure patients undergoing haemodialysis. Spectral powers were calculated from the low frequency (LF, 0.04-0.145 Hz) and high frequency (HF, 0.145-0.45 Hz) bands. In eight stable fluid overloaded patients (fluid removal of >2 L) not on alpha blockers, progressive reduction in relative blood volume during haemodialysis resulted in significant increase in LF and HF powers of PPG baseline and amplitude variability (P < 0.01), when expressed in mean-scaled units. The augmentation of LF powers in PPGV during haemodialysis may indicate the recovery and possibly further enhancement of peripheral sympathetic vascular modulation subsequent to volume unloading, whilst the increase in respiratory HF power in PPGV is most likely a sign of preload reduction. Spectral analysis of finger PPGV may provide valuable information on the autonomic vascular response to blood volume reduction in haemodialysis, and can be potentially utilized as a non-invasive tool for assessing peripheral circulatory control during routine dialysis procedure.

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Cited by 27 publications

References 0 publications

Augmented photoplethysmographic low frequency waves at the onset of endotoxic shock in rabbits

Augmented photoplethysmographic low frequency waves at the onset of endotoxic shock in rabbits

Ambient temperature effect on pulse rate variability as an alternative to heart rate variability in young adult

Frequency spectrum analysis of finger photoplethysmographic waveform variability during haemodialysis

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