Fuerza muscular respiratoria y movilidad torácica en niños sanos. Relación con medidas antropométricas / Respiratory muscle strength and thoracic mobility in healthy children. Relationship with anthropometric measurements

INTRODUCCIÓN: La medición de la fuerza muscular respiratoria y la movilidad torácica tienen importancia en la evaluación clínica del sistema respiratorio en población pediátrica, sin embargo, sus valores pueden cambiar por las características de la población de cada país. El objetivo del estudio fue describir la fuerza muscular respiratoria y movilidad torácica en niños sanos de Cali, Colombia y analizar la correlación con medidas antropométricas. MATERIALES Y MÉTODOS: Estudio transversal. Se incluyeron niños sanos entre 8 y 11 años de un colegio de Cali, Colombia a quienes se les midió la fuerza muscular respiratoria con la Presión Inspiratoria Máxima (PIM) y Presión Espiratoria Máxima (PEM) y la movilidad torácica con la cirtometría axilar y xifoidea. También se tomaron las medidas antropométricas peso, talla e IMC para la edad. RESULTADOS: Se admitieron 89 niños, un 50,6% de sexo femenino y con IMC en normopeso para la edad del 62,9%. Mediana de PIM -60,0 cmH2O (Rango Intercuartílico [RIQ] 44,0) y PEM 49,0 cmH2O (RIQ 19,0). Mediana de cirtometría axilar 4,5 cm (RIQ 1,6) y xifoidea 4,7 cm (RIQ 1,7). La PIM tuvo correlación con el índice de masa corporal (IMC) para la edad (rs = 0,23 p = 0,030), la cirtometría axilar con el peso (rs = 0,35; p = 0,001) y el IMC para la edad (rs = 0,31; p = 0,003), la cirtometría xifoidea con el peso (rs = 0,24; p = 0,027) y la talla (rs = 0,22; p = 0,037). No hubo correlación entre la PIM-PEM y cirtometría. DISCUSIÓN: La fuerza muscular respiratoria y la movilidad torácica dependen de los cambios experimentados en el crecimiento del infante y de características diferenciales entre niños y niñas durante la pubertad

INTRODUCTION: The measurement of respiratory muscle strength and thoracic mobility are important in clinical assessment of the respiratory system in the paediatric population, however, their values can change according to the characteristics of the population of each country. The objective of the study was to describe respiratory muscle strength and thoracic mobility in healthy children from Cali, Colombia, and analyse their correlation with anthropometric measurements. MATERIALS AND METHODS: A cross-sectional study. We included healthy children between 8 and 11 years old, from a school in Cali, Colombia, whose respiratory muscle strength was measured with Maximum Inspiratory Pressure (MIP) and Maximum Expiratory Pressure (MEP) and thoracic mobility with axillary and xiphoid cirtometry. Anthropometric measurements were taken, such as weight, height and BMI-for-age. RESULTS: 89 children were admitted, most were female (50.6%) and with normal BMI-for-age (62.9%). Median MIP -60.0 cmH2O (IQR 44.0) and MEP 49.0 cmH2O (IQR 19.0). Median axillary cirtometry 4.5 cm (IQR 1.6) and xiphoid cirtometry 4.7 cm (IQR 1.7). MIP correlated with BMI-for-age (rs = 0.23 p = 0.030), axillary cirtometry with weight (rs = 0.35 p = 0.001) and BMI-for-age (rs = 0.31 p = 0.003), xiphoid cirtometry with weight (rs = 0.24 p = 0.027) and height (rs = 0.22 p = 0.037). There was no correlation between MIP-MEP and cirtometry. DISCUSSION: Respiratory muscle strength and thoracic mobility depend on changes in the growth of the infant and differential characteristics between boys and girls during puberty

Effects of gender and posture on thoraco-abdominal kinematics during quiet breathing in healthy adults.

To investigate the effects of posture and gender on thoraco-abdominal motion and breathing pattern, 34 healthy men and women were studied by Opto-Electronic Plethysmography during quiet breathing in five different postures from seated (with and without back support) to supine position. Chest wall kinematics and breathing pattern were significantly influenced by position and gender. The progressively increased inclination of the trunk determined a progressive reduction of rib cage displacement, tidal volume, and minute ventilation and a progressive increase of abdominal contribution to tidal volume. Female subjects were characterized by smaller dimensions of the rib cage compartment and during quiet breathing by lower tidal volume, minute ventilation and abdominal contribution to tidal volume than males. The effect of posture on abdominal kinematics was significant only in women. The presence of a back support in seated position determined differences in breathing pattern. In conclusion, posture and gender have a strong influence on breathing and on chest wall kinematics.

A model for studies of the deformable rib cage.

An earlier model for the study of rib cage mechanics was modified so that rib deformity in scoliosis could be better represented. The rigid ribs of that model were replaced by five-segment deformable ribs. Literature data on cadaver rib mechanical behavior were used to assign stiffnesses to the new individual model ribs so that experimental and model rib deflections agreed. Shear and tension/compression stiffnesses had little effect on individual rib deformation, but bending stiffnesses had a major effect. Level-to-level differences in mechanical behavior could be explained almost exclusively by level to level differences in the rib shape. The model ribs were then assembled into a whole rib cage. Computer simulations of whole rib cage behaviors, both in vivo and in vitro, showed a reasonable agreement with the measured behaviors. The model was used to study rib cage mechanics in two scolioses, one with a 43 degrees and the other with a 70 degrees Cobb angle. Scoliotic rib cage deformities were quantified by parameters measuring the rib cage lateral offset, rib cage axial rotation, rib cage volume and rib distortion. Rib distortion was quantified both in best-fit and simulated computer tomography (CT) scan planes. Model rib distortion was much smaller in best-fit planes than in CT planes. The total rib cage volume changed little in the presence of the scolioses, but it became asymmetrically distributed.