Estudo sobre a adaptação microcirculatória in vivo à contração isométrica flexão dorsal no membro inferior humano
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Data
2018
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Edições Universitárias Lusófonas
Resumo
O fluxo sanguíneo nas extremidades inferiores varia consideravelmente devido a mudanças de pressão causadas
pela contração muscular, por exemplo da bomba muscular da região posterior da perna. A flexão dorsal está
associada ao desempenho funcional da marcha e a relação com a microcirculação dos membros inferiores, ainda
não foi abordada. Neste estudo, exploramos o impacto da flexão dorsal na microcirculação do membro inferior com
tecnologias não invasivas, o mais próximo possível do estado fisiológico normal. Seis sujeitos saudáveis jovens (31
± 9 anos) participaram neste estudo após consentimento por escrito. O protocolo experimental consistiu em 5 min
de pé, 1 min de contração dos flexores dorsais e 5 minutos de recuperação na posição inicial. A microcirculação
foi avaliada por fotopletismografia (FPG) e pelo método de fluxometria por laser Doppler (FLD). A frequência
de pulso (FP) foi obtida de FPG. Foram utilizadas estatísticas não paramétricas para a comparação entre as fases.
A flexão dorsal modificou significativamente a perfusão local com a FPG a registar uma diminuição (p = 0,028)
enquanto o FLD registou um aumento significativo (p = 0,028). A FP não se alterou durante o protocolo. A flexão
dorsal parece causar respostas diferentes nas redes microvasculares da pele, o que pode ser atribuído às diferentes
profundidades de medição das técnicas utilizadas, o que justifica novos estudos.
Blood flow in the lower extremities varies considerably due to changes in pressure from muscle contraction as occurs with calf muscle pump activity. The dorsiflexion is associated with functional walking performance, and its relation with microcirculation of lower limbs has not yet been addressed. In this study we explore the impact of dorsiflexion in the lower limb microcirculation with non-invasive technologies, as near as possible to the normal physiological state. Six (31 ± 9 years) healthy subjects were enrolled in this study after informed written consent. The experimental protocol consisted of 5 minutes standing, 1 minute of dorsiflexor muscle group contraction, and 5 minutes recovery in the initial position. Microcirculation was evaluated by photoplethysmography (PPG) and laser Doppler flowmetry (LDF). Pulse rate (PR) was obtained from PPG. Nonparametric statistics were used for phase comparisons. Dorsiflexion significantly modified the local perfusion, with PPG registering a decrease (p=0.028) while LDF registered an increase (p=0.028). PR did not change during the procedure. Foot dorsiflexion seems to cause different responses in the skin microvascular networks which might be attributed to the different measuring depths of the techniques employed, justifying further studies.
Blood flow in the lower extremities varies considerably due to changes in pressure from muscle contraction as occurs with calf muscle pump activity. The dorsiflexion is associated with functional walking performance, and its relation with microcirculation of lower limbs has not yet been addressed. In this study we explore the impact of dorsiflexion in the lower limb microcirculation with non-invasive technologies, as near as possible to the normal physiological state. Six (31 ± 9 years) healthy subjects were enrolled in this study after informed written consent. The experimental protocol consisted of 5 minutes standing, 1 minute of dorsiflexor muscle group contraction, and 5 minutes recovery in the initial position. Microcirculation was evaluated by photoplethysmography (PPG) and laser Doppler flowmetry (LDF). Pulse rate (PR) was obtained from PPG. Nonparametric statistics were used for phase comparisons. Dorsiflexion significantly modified the local perfusion, with PPG registering a decrease (p=0.028) while LDF registered an increase (p=0.028). PR did not change during the procedure. Foot dorsiflexion seems to cause different responses in the skin microvascular networks which might be attributed to the different measuring depths of the techniques employed, justifying further studies.
Descrição
Biomedical and biopharmaceutical research : jornal de investigação biomédica e biofarmacêutica
Palavras-chave
MEDICINA, MICROCIRCULAÇÃO, FOTOPLETISMOGRAFIA, FLUXOMETRIA POR LASER-DOPPLER, MEMBROS INFERIORES, MEDICINE, MICROCIRCULATION, PHOTOPLETHYSMOGRAPHY, LASER-DOPPLER FLOWMETRY, LOWER EXTREMITY