ABSTRACT
RESUMEN En el niño, la microcirculación cutánea (MCC) experimenta cambios desde sus primeros días de vida hasta la adolescencia. Mediante la video capilaroscopia (VC), se puede acceder a la visualización in vivo e incruenta de la MCC, en niños de cualquier edad. El sitio de elección es el pliegue peri ungular de los dedos de las manos. Se observan las asas capilares, dispuestas en corona sobre la matriz peri ungular y el plexo vascular superficial. Los recién nacidos presentan una red primitiva. Posteriormente, evolucionaalcanzando alrededor de los 10 años, los parámetros similares al adulto.El conocimiento de los parámetros de la MCC preservada en niños,será de gran importancia en la exploración diagnóstica de las patologías que afectan este territorio vascular, como las enfermedades reumáticas.
SUMMARY The child's skin microcirculation (MCC) undergoes changes from the first days of life until adolescence. Through video capillaroscopy (VC), in vivo and non-invasive visualization of the CCM is accessed in children of any age. The site of the election is the nail fold of the fingers of the hands. The capillary loops arranged in a crown over the nail matrix and the superficial vascular plexus are observed. The newborns present a primitive network, which later evolves reaching around 10 years the parameters similar to the adult. There are structural differences in MCC if the findings in children are compared with those of adults. In children the capillary density per linear millimeter is lower, the tortuosity index is higher, the superficial vascular plexus is more visible and bizarre capillary forms are found Knowledge of the parameters of MCC preserved in children will be of great importance in the diagnostic exploration of pathologies that affect this vascular territory such as rheumatic diseases.
ABSTRACT
OBJECTIVE: An awareness of the repeatability of biological measures is required to properly design and calculate sample sizes for longitudinal interventional studies. We investigated the day-to-day repeatability of measures of systemic microvascular reactivity using laser Doppler perfusion monitoring. METHODS: We performed laser Doppler perfusion monitoring in combination with skin iontophoresis using acetylcholine and sodium nitroprusside as well as post-occlusive reactive and thermal hyperemia twice within two weeks. The repeatability was assessed by calculating the within-subject standard deviations, limits of agreement, typical errors and intra-class correlation coefficients between days 1 and 2. The ratio of the within-subject standard deviation to the mean values obtained on days 1 and 2 (within-subject standard deviation/GM) was used to determine the condition with the best repeatability. RESULTS: Twenty-four healthy subjects, aged 24.6 + 3.8 years, were recruited. The area under the curve of the vasodilatory response to post-occlusive reactivity showed marked variability (within-subject standard deviation/GM = 0.83), while the area under the curve for acetylcholine exhibited less variability (within-subject standard deviation/ GM = 0.52) and was comparable to the responses to sodium nitroprusside and thermal treatment (within-subject standard deviations/GM of 0.67 and 0.56, respectively). The area under the blood flow/time curve for vasodilation during acetylcholine administration required the smallest sample sizes, the area under the blood flow/time curve during post-occlusive reactivity required the largest sample sizes, and the area under the blood flow/time curves of vasodilation induced by sodium nitroprusside and thermal treatment required intermediate sizes. CONCLUSIONS: In view of the importance of random error related to the day-to-day repeatability of laser Doppler perfusion monitoring, we propose an original and robust statistical methodology for use in designing prospective clinical studies.