Pedro Miguel Gewehr

Obesity Impact Evaluated from Fat Percentage in Bone Mineral Density of Male Adolescents.

Objective To analyze bone mineral density (BMD) values in adolescents and to assess obesity impact, measured through body fat #x2013;on this variable through the assessment by DEXA. Methodology A total of 318 males adolescents (12–17 years) were evaluated considering weight, height, body mass index (BMI), bone mineral density (BMD), fat and lean mass. BMD was assessed for the arms, legs, hips, and lumbar regions, as well as for total amount. Stratification of the nutritional status was determined by body fat (%BF) percentage; comparison of groups was scrutinized by analysis of variance; and the association of variables was performed using Pearsons test. Results There was a progressive increase in weight, height, and BMD for all evaluated age groups following the advance of chronological age. A negative correlation was found between the %BF with BMD in all evaluated segments. Significant differences were found between the eutrophic group compared to the overweight group and the obesity group in the evaluated segments (P <0.01) noting a reduction of up to 12.92% for the lumbar region between eutrophic and obese. Conclusion The results suggest that increase %BF is associated with lower BMD among male adolescents.

PETCO2 measurement and feature extraction of capnogram signals for extubation outcomes from mechanical ventilation

Capnography is a continuous and noninvasive method for carbon dioxide (CO2) measurement, and it has become the standard of care for basic respiratory monitoring for intubated patients in the intensive care unit. In addition, it has been used to adjust ventilatory parameters during mechanical ventilation (MV). However, a substantial debate remains as to whether capnography is useful during the process of weaning and extubation from MV during the postoperative period. Thus, the main objective of this study was to present a new use for time-based capnography data by measuring the end-tidal CO2 pressure ([Formula: see text]), partial pressure of arterial CO2 ([Formula: see text]) and feature extraction of capnogram signals before extubation from MV to evaluate the capnography as a predictor of outcome extubation in infants after cardiac surgery. Altogether, 82 measurements were analysed, 71.9% patients were successfully extubated, and 28.1% met the criteria for extubation failure within 48 h. The ROC-AUC analysis for quantitative measure of the capnogram showed significant differences (p < 0.001) for: expiratory time (0.873), slope of phase III (0.866), slope ratio (0.923) and ascending angle (0.897). In addition, the analysis of [Formula: see text] (0.895) and [Formula: see text] (0.924) obtained 30 min before extubation showed significant differences between groups. The [Formula: see text] mean value for success and failure extubation group was 39.04 mmHg and 46.27 mmHg, respectively. It was also observed that high CO2 values in patients who had returned MV was 82.8  ±  21 mmHg at the time of extubation failure. Thus, [Formula: see text] measurements and analysis of features extracted from a capnogram can differentiate extubation outcomes in infant patients under MV, thereby reducing the physiologic instability caused by failure in this process.

Portable A-Mode Ultrasound for Body Composition Assessment in Adolescents

Ultrasound (US) imaging is a low‐cost, highly feasible alternative method for monitoring the nutritional status of a population; however, only a few studies have tested the body composition agreement between US and reference standard methods, especially in adolescents. The purposes of this study were to assess the agreement of portable US with a reference standard method, dual‐energy x‐ray absorptiometry (DXA), for body fat percentage (BF%) in adolescents and to verify whether the use of a new mathematical model, based on the anatomic thickness obtained by US, is capable of improving BF% prediction.

Measurement of End-Tidal Carbon Dioxide in Spontaneously Breathing Children After Cardiac Surgery

BACKGROUND Respiratory monitoring is important after surgery to prevent pulmonary complications. End-tidal carbon dioxide (Petco(2)) measurement by capnometry is an indirect and noninvasive measurement of Pco(2) in blood and is accepted and recognized in critical care. OBJECTIVES To determine the correlation and level of agreement between Petco(2) and Paco(2) in spontaneously breathing children after cardiac surgery and to determine whether Petco(2) measured by using tidal volume (Vt-Petco(2)) or vital capacity (VC-Petco(2)) shows more or less significant correlation with Paco(2). METHODS Vt-Petco(2) and VC-Petco(2) by capnometry and Paco(2) by blood gas analysis were measured once a day after tracheal extubation. The determination coefficient and degree of bias between the methods were assessed in children with and without supplemental oxygen. RESULTS A total of 172 Vt-Petco(2), VC-Petco(2), and Paco(2) values from 48 children were analyzed. The overall coefficients of determination were 0.84 (P < .001) for Vt-Petco(2) and Paco(2) and 0.62 (P = .02) for VC-Petco(2) and Paco(2). The mean gradient for Paco(2) to Petco(2) in all groups increased with the increase in supplemental oxygen; the gradient was significantly larger in the groups given 2 to 5 L of oxygen per minute. CONCLUSIONS In spontaneously breathing children, Vt-Petco(2) provided a more accurate estimate of Paco(2) than did VC-Petco(2), especially in children given little or no supplemental oxygen. The difference between the methods was significantly larger in the groups given 2 to 5 L of oxygen per minute.

Body composition and prediction equations using skinfold thickness for body fat percentage in Southern Brazilian adolescents

Objectives The purpose of this study was to: a) determine the nutritional status of Brazilian adolescents, and; b) present a skinfold thickness model (ST) to estimate body fat developed with Brazilian samples, using dual energy x-ray absorptiometry (DXA) as reference method. Methods The main study group was composed of 374 adolescents, and further 42 adolescents for the validation group. Weight, height, waist circumference measurements, and body mass index (BMI) were collected, as well as nine ST–biceps (BI), triceps (TR), chest (CH), axillary (AX) subscapularis (SB), abdominal (AB), suprailiac (SI), medial thigh (TH), calf (CF), and fat percentage (%BF) obtained by DXA. Results The prevalence of overweight in adolescents was 20.9%, and obesity 5.8%. Regression analysis through ordinary least square method (OLS) allowed obtainment of three equations with values of R2 = 0.935, 0.912 and 0.850, standard error estimated = 1.79, 1.78 and 1.87, and bias = 0.06, 0.20 and 0.05, respectively. Conclusion the innovation of this study lies in presenting new regression equations for predicting body fat in Southern Brazilian adolescents based on a representative and heterogeneous sample from DXA.

Fat percentage evaluation through portable ultrasound in adolescents: A comparison with dual energy X-ray absorptiometry

Ultrasound has been pointed as a low cost and extremely practical new tool for monitoring body composition and obesity. Thus, this study aims at analyzing the performance of portable US, in comparison with dual energy X-ray absorptiometry (DXA) reference method, in specific equations for predicting fat percentage on male adolescents. 143 male adolescents aged from 12 to 17 years old were evaluated and data on corporal mass, height and fat percentage were collected by US (%BF US) and DXA (%BF). The initial evaluation showed an under estimation of the US method (mean = 10.57 % and standard deviation = 4.45%) in comparison with DXA reference method (mean = 19.94 % and standard deviation = 5.36%). The creation of a specific model, developed from the US measurements, allowed values of R2 = 0.853 with standard error of the estimate = 1.49. Bland-Altman concordance graphic analysis did not present significant bias. Results suggest that it is possible to use portable US technology to evaluate fat percentage in adolescents, provided that a specific mathematical modeling is used.

2D and 3D Photogrammetric Models for Respiratory Analysis in Adolescents

The aim of this study was to test the correlation between a two dimensional (2D) and three dimensional (3D) biomechanical photogrammetric model, with inspiratory and expiratory lung capacities in adolescents. This was a cross sectional study, in which 40 adolescents of both genders were assessed, aged between 14 and 17 years old. Anthropometric data were collected (body mass, height and thorax length). Then, three tests were performed for forced vital capacity (FVC) in the supine position, using a spirometer. For FVC proof assessments, the volunteers were subjected to a mapping of body structures with adhesive markers and, after the test, one was selected with better respiratory performance for computational analysis of photogrammetric thoracoabdominal mobility. The results showed average values of 15.40, 61.29, 1.66 and 25.54, for age (years), body mass (kg), height (m) and thorax length (cm), respectively. The analysis found respiratory values of: 3:22 l for forced expiratory volume in one second, 3.87 l for forced vital capacity, 6.50 l/s for peak expiratory flow and 3.59 l for deep inspiration. The correlation showed better values for 3D photogrammetry as compared to 2D. The inclusion of the third dimension has been applied in order to adequate photogrammetric methodology to existing kinematics analysis tools as videogrammetry computed and plethysmography.