O impacto da contração isométrica da perna na microcirculação local
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Data
2017
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Edições Universitárias Lusófonas
Resumo
A atividade da bomba muscular é um mecanismo que facilita o retorno venoso. A fraqueza muscular do membro inferior
pode diminuir a eficácia da bomba muscular da perna e comprometer um adequado retorno venoso. O objetivo deste
estudo foi propor um modelo experimental para avaliar o impacto da bomba muscular da perna na microcirculação.
Para o efeito, estudamos a resposta microvascular periférica à atividade isométrica da bomba muscular da perna, na
posição de pé. Seis indivíduos saudáveis (31 ± 9 anos) participaram deste estudo após terem dado o consentimento
informado. Após 5 min na posição de pé, os indivíduos realizaram 1 min de flexão plantar isométrica mantida, dos dois
pés, antes de retomar a posição inicial por mais 5 min. A perfusão da pele do pé foi avaliada com fotopletismografia
(FPG) e com fluxometria por laser Doppler (FLD), a frequência de pulso (FP) foi calculada a partir da FPG e a atividade
muscular da perna com eletromiografia (EMG). Foram utilizadas estatísticas não paramétricas para comparação das
fases. Durante a atividade da perna, observámos diferenças significativas de onda FPG e da amplitude de FLD com
uma rápida recuperação após o final da contração do músculo. A frequência de pulso não mudou durante as três fases do
protocolo. Esses resultados sugerem a utilidade do modelo proposto para explorar futuramente, o impacto da atividade
da bomba muscular da perna na microcirculação periférica.
The muscle pump activity is an important component of venous return. Muscle weakness in the lower limb can decrease the efficacy of the calf muscle pump and compromise adequate venous return. The aim of this study was to propose an experimental model to evaluate the impact of the calf muscular pump influence on peripheral microcirculation. We studied the local microvascular response to isometric calf contraction in the standing position. Six healthy subjects (31± 9 years old) participated in this study after giving informed consent. After standing for 5 minutes, subjects performed 1 minute of maintained isometric plantar flexion with both feet before resuming the original position for another 5 minutes. Local (foot) perfusion was evaluated with photoplethysmography (PPG) and laser Doppler flowmetry (LDF), pulse rate (PR) obtained from the PPG, and calf muscle activity was followed by electromyography (EMG). Nonparametric statistics were used for phase comparisons. During calf pump activity we observed significant differences of wave PPG and LDF amplitude with a rapid replacement after calf muscle contraction stopped. Pulse rate did not change during the three protocol phases. Thus, this proposed model appears suitable to further explore the role of the muscular pump activity on the peripheral microcirculation.
The muscle pump activity is an important component of venous return. Muscle weakness in the lower limb can decrease the efficacy of the calf muscle pump and compromise adequate venous return. The aim of this study was to propose an experimental model to evaluate the impact of the calf muscular pump influence on peripheral microcirculation. We studied the local microvascular response to isometric calf contraction in the standing position. Six healthy subjects (31± 9 years old) participated in this study after giving informed consent. After standing for 5 minutes, subjects performed 1 minute of maintained isometric plantar flexion with both feet before resuming the original position for another 5 minutes. Local (foot) perfusion was evaluated with photoplethysmography (PPG) and laser Doppler flowmetry (LDF), pulse rate (PR) obtained from the PPG, and calf muscle activity was followed by electromyography (EMG). Nonparametric statistics were used for phase comparisons. During calf pump activity we observed significant differences of wave PPG and LDF amplitude with a rapid replacement after calf muscle contraction stopped. Pulse rate did not change during the three protocol phases. Thus, this proposed model appears suitable to further explore the role of the muscular pump activity on the peripheral microcirculation.
Descrição
Biomedical and biopharmaceutical research : jornal de investigação biomédica e biofarmacêutica
Palavras-chave
MEDICINA, MEMBROS INFERIORES, MICROCIRCULAÇÃO, FLUXOMETRIA POR LASER-DOPPLER, FOTOPLETISMOGRAFIA, MEDICINE, LOWER EXTREMITY, MICROCIRCULATION, LASER-DOPPLER FLOWMETRY, PHOTOPLETHYSMOGRAPHY