Combinando a fluxometría por laser-doppler e a fotopletismografia na exploração da fisiologia vascular in vivo
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2016
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Edições Universitárias Lusófonas
Resumo
A fluxometria por laser Doppler (FLD) e a fotopletismografia (FPG) são duas técnicas óticas bem conhecidas, que possibilitam a gravação em tempo real in vivo de leituras sensíveis do fluxo sanguíneo. Apenas alguns estudos utilizaram recolha de dados de perfusão com as duas técnicas em simultâneo, significando que pouco se conhece sobre a utilidade deste uso combinado. O nosso objetivo foi o de avaliar a resposta vascular em indivíduos saudáveis para uma manobra de provocação com ambas as técnicas. Doze voluntários (ambos os sexos, 26.0 ± 5.0 anos), foram selecionados após obtenção de consentimento informado. A manobra escolhida foi a manobra de pendência da perna, com a FLD e FPG registadas em ambos os pés, registando-se também a pressão transcutânea (tc) de O2 obtida por gasimetria e a frequência de pulso (FP) calculada a partir do sinal FPG. O teste de Wilcoxon para amostras emparelhadas foi usado para comparação das diferentes fases (p<0.05). A perna pendente reduziu de forma significativa a perfusão em ambos os pés, embora de modo mais significativa no pé pendente. O reflexo venoarteriolar (RVA) explica esta vasoconstrição, enquanto que no pé imóvel, um reflexo medular poderá estar envolvido. A tcpO2 aumentou significativamente durante o abaixamento da perna, o que sugere que o aquecimento da sonda anulou o RVA na zona de medição. Não se verificaram alterações em termos de FP. Este estudo parece confirmar que o uso combinado de FLD e FPG pode ajudar a olhar com maior profundidade para a fisiologia da microcirculação periférica.
Laser Doppler flowmetry (LDF) and photoplethysmography (PPG) are two well-known optical techniques, allowing sensible real-time in vivo recording of blood flow. Only a few studies have used simultaneous perfusion recordings with both techniques, meaning that not much is known regarding the utility of their combined use. Our aim was to assess the vascular response of healthy individuals to a challenge maneuver with both techniques. Twelve subjects (both sexes, 26.0 ± 5.0 years old), were selected after informed written consent. The chosen maneuver was the leg pending maneuver, with LDF and PPG being assessed in both feet, and with transcutaneous O2 (tc) pressure obtained by gasimetry, and pulse rate (PR) calculated from the PPG signal, being also registered. The Wilcoxon signed-rank test was used for phase comparisons (p<0.05). Leg pending significantly reduced perfusion on both feet, although more clearly on the pending foot. The venoarterial reflex explains this vasoconstriction while, in the unmoved foot, a centrally-mediated reflex might be involved. tcpO2 increased significantly during leg lowering, suggesting that the heat from the probe cancelled the venoarteriolar reflex (VAR) on the measurement region. No changes were seen in HR. This study seems to confirm that the combined use of LDF and PPG might help to look deeper into peripheral microcirculation mechanisms.
Laser Doppler flowmetry (LDF) and photoplethysmography (PPG) are two well-known optical techniques, allowing sensible real-time in vivo recording of blood flow. Only a few studies have used simultaneous perfusion recordings with both techniques, meaning that not much is known regarding the utility of their combined use. Our aim was to assess the vascular response of healthy individuals to a challenge maneuver with both techniques. Twelve subjects (both sexes, 26.0 ± 5.0 years old), were selected after informed written consent. The chosen maneuver was the leg pending maneuver, with LDF and PPG being assessed in both feet, and with transcutaneous O2 (tc) pressure obtained by gasimetry, and pulse rate (PR) calculated from the PPG signal, being also registered. The Wilcoxon signed-rank test was used for phase comparisons (p<0.05). Leg pending significantly reduced perfusion on both feet, although more clearly on the pending foot. The venoarterial reflex explains this vasoconstriction while, in the unmoved foot, a centrally-mediated reflex might be involved. tcpO2 increased significantly during leg lowering, suggesting that the heat from the probe cancelled the venoarteriolar reflex (VAR) on the measurement region. No changes were seen in HR. This study seems to confirm that the combined use of LDF and PPG might help to look deeper into peripheral microcirculation mechanisms.
Descrição
Biomedical and biopharmaceutical research : jornal de investigação biomédica e biofarmacêutica
Palavras-chave
MEDICINA, MEIOS DE DIAGNÓSTICO, FLUXOMETRIA POR LASER-DOPPLER, MICROCIRCULAÇÃO, FOTOPLETISMOGRAFIA, MEDICINE, DIAGNOSTIC PROCEDURES, LASER-DOPPLER FLOWMETRY, MICROCIRCULATION, PHOTOPLETHYSMOGRAPHY
Citação
Silva , H , Rocha , C & Rodrigues , L M 2016 , ' Combinando a fluxometría por laser-doppler e a fotopletismografia na exploração da fisiologia vascular in vivo ' , Biomedical and biopharmaceutical research : jornal de investigação biomédica e biofarmacêutica .