Investigation of photoplethysmography, laser doppler flowmetry and near infrared spectroscopy during induced thermal stress

Budidha, Karthik; Abay, Tomas Ysehak; Kyriacou, Panayiotis A.

doi:10.1109/embc.2015.7319861

Cited by 4 publications

(4 citation statements)

References 9 publications

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“…In fact, perfusion changes decreased significantly with PPG (p=0.028) while they increased significantly with LDF (p=0.028) ( Table 1). These results are in line with previous findings that suggest that these differences might be related to the depth of measurement for each technique, [9] as PPG seems to measure in deeper regions than LDF [10] . Skin has a very compliant circulation and, in presence of a mechanism that causes variations in blood flow, the response may be different according to the microvascular networks where the signal is recorded [11][12] .…”

Section: Resultssupporting

confidence: 93%

“…De fato, as alterações de perfusão diminuíram significativamente com FPG (p = 0,028), enquanto aumentaram significativamente com FLD (p = 0,028) (tabela 1). Estes resultados estão em linha com achados anteriores que sugerem que essas diferenças podem estar relacionadas com a profundidade de medida para cada técnica [9] , onde FPG parece medir em regiões mais profundas do que FLD [10] . A pele tem uma circulação muito complacente e, na presença de um mecanismo que causa variações no fluxo sanguíneo, a resposta pode ser diferente de acordo com as redes microvasculares onde o sinal é gravado [11][12] .…”

Section: Resultsunclassified

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Studying the in vivo microcirculatory adaptation to isometric contraction (dorsiflexion) in the human lower limb

Florindo

Silva

Rodrigues

2018

BBR

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Section: Resultssupporting

confidence: 93%

Section: Resultsunclassified

Studying the in vivo microcirculatory adaptation to isometric contraction (dorsiflexion) in the human lower limb

Florindo

Silva

Rodrigues

2018

BBR

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“…The lower SpO 2 value for the finger at low temperature is mainly due to the profound vasoconstriction caused by the activation of the sympathetic nervous system. [ 42 ]…”

Section: Resultsmentioning

confidence: 99%

A Skin‐Mountable Hyperthermia Patch Based on Metal Nanofiber Network with High Transparency and Low Resistivity toward Subcutaneous Tumor Treatment

Wang

Sheng

et al. 2022

Adv Funct Materials

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A wearable hyperthermia device that allows for tumor treatment without interfering with daily activities is of clinical and social significance. However, the wide adaptation of local hyperthermia from such wearable devices in clinical practice has been hindered mainly due to several critical challenges in existing hyperthermia devices, such as the contradiction of high electrical conductivity and high optical transparency of the device while in a thin, deformable format. Here a soft, skin-mountable, hyperthermia patch (HTP) is reported with unusual optical and electrical characteristics based on unidirectional silver nanofibers (AgNFs) network with low-voltage operation and uniform heating even under mechanical deformation. The patch presents both high electrical conductivity and highly optical transparency simultaneously thus allowing real time inspection of the subcutaneous tumor treatment and skin response during the treatment. The unidirectional nature of the AgNFs network renders the key features of high optical transparency, low electrical resistivity, excellent electrothermal performances, and mechanical deformability. Effective treatment of subcutaneous tumors in mice is demonstrated with the skin worn HTP while the skin response is visually tracked. Systematic studies reveal the physiological mechanisms of Notch signaling in inducing tumor cell apoptosis.

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“…Near infrared spectroscopy is proposed as a reliable index of muscle blood flow and O 2 uptake in normothermia (18) and following local or whole body cold exposure (7,10), and it was used to explore how cerebral and muscle oxygenation responses during exercise are affected by cooling and/or hyperoxia. Both cerebral and muscle oxygenation were elevated in ColdϩHyper compared with Cold.…”

Section: Discussionmentioning

confidence: 99%

Effects of mild whole body hypothermia on self-paced exercise performance

Ferguson

Eves

Roy

et al. 2018

Journal of Applied Physiology

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This study examined self-paced, high-intensity exercise during mild hypothermia and whether hyperoxia might offset any potential impairment. Twelve trained males each completed 15-km time trials in three environmental conditions: Neutral (23°C, [Formula: see text] 0.21), Cold (0°C, [Formula: see text] 0.21), and Cold+Hyper (0°C, [Formula: see text] 0.40). Cold and Cold+Hyper trials occurred after a 0.5°C drop in rectal temperature. Rectal temperature was higher ( P ≤ 0.016) throughout Neutral compared with Cold and Cold+Hyper; Cold had a higher ( P ≤ 0.035) rectal temperature than Cold+Hyper from 2.5 to 7.5 km, and hyperoxia did not alter thermal sensation or comfort. Oxyhemoglobin saturation decreased from ~98% to ~94% with Neutral and Cold, but was maintained at ~99% in Cold+Hyper ( P < 0.01). Cerebral tissue oxygenation index (TOI) was higher in Neutral than in Cold throughout the time trial (TT) ( P ≤ 0.001), whereas Cold+Hyper were unchanged ( P ≥ 0.567) from Neutral by 2.5 km. Muscle TOI was maintained in Cold+Hyper compared with Neutral and was higher ( P ≤ 0.046) than Cold throughout the entire TT. Power output during Cold (246 ± 41 W) was lower than Neutral (260 ± 38 W) at all 2.5-km intervals ( P ≤ 0.012) except at 12.5 km. Power output during Cold+Hyper (256 ± 42 W) was unchanged ( P ≥ 0.161) from Neutral throughout the TT, and was higher than Cold from 7.5 km onward. Average cadence was higher in Neutral (93 ± 8 rpm) than in either Cold or Cold+Hyper (Cold: 89 ± 7 and Cold+Hyper: 90 ± 8 rpm, P = 0.031). In conclusion, mild hypothermia reduced self-paced exercise performance; hyperoxia during mild hypothermia restored performance to thermoneutral levels, likely due to maintenance of oxygen availability rather than any thermogenic benefit. NEW & NOTEWORTHY We examined self-paced, high-intensity exercise with 0.5°C rectal temperature decreases in a 0°C ambient environment, along with whether hyperoxia could offset any potential impairment. During a 15-km time trial, power output was lower with hypothermia than with thermoneutral. However, with hypothermia, hyperoxia of [Formula: see text] = 0.40 restored power output despite there being no thermophysiological improvement. Hypothermia impairs exercise performance, whereas hyperoxia likely restored performance due to maintenance of oxygen availability rather than any thermogenic benefit.

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Investigation of photoplethysmography, laser doppler flowmetry and near infrared spectroscopy during induced thermal stress

Cited by 4 publications

References 9 publications

Studying the in vivo microcirculatory adaptation to isometric contraction (dorsiflexion) in the human lower limb

Studying the in vivo microcirculatory adaptation to isometric contraction (dorsiflexion) in the human lower limb

A Skin‐Mountable Hyperthermia Patch Based on Metal Nanofiber Network with High Transparency and Low Resistivity toward Subcutaneous Tumor Treatment

Effects of mild whole body hypothermia on self-paced exercise performance

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