Reliability and validity of the lung volume measurement made by the BOD POD body composition system.

The BOD POD Body Composition System uses air-displacement plethysmography to measure body volume. To correct the body volume measurement for the subject's lung volume, the BOD POD utilizes pulmonary plethysmography to measure functional residual capacity (FRC) at mid-exhalation as that is the subject's lung volume during the body volume measurement. Normally, FRC is measured at end-exhalation. The BOD POD FRC measurement can be corrected to an end-exhalation volume by subtracting approximately one-half of the measured tidal volume. Our purpose was to determine the reliability and validity of the BOD POD FRC measurement at end-exhalation. Ninety-two healthy adults (half female) underwent duplicate FRC measurements by the BOD POD and one FRC measurement by a traditional gas dilution technique. The latter method was used as the reference method for the validity component of the study. The order of the FRC measurements by the two methods was randomized. The test-retest correlation coefficients for the duplicate BOD POD FRC measurements for the male and female subjects were 0.966 and 0.948, respectively. The mean differences between the BOD POD FRC trial #1 measurement and gas dilution FRC measurement for the male and female subjects were -32 and -23 ml, respectively. Neither difference was statistically significant. The correlation coefficients for these two measurements in the male and female subjects were 0.925 and 0.917, respectively. Based on these results, we conclude that the BOD POD FRC measurement in healthy males and females is both reliable and valid.

Test-retest reliability for two indices of ventilatory efficiency measured during cardiopulmonary exercise testing in healthy men and women.

The level of ventilation (VE)) at a given carbon dioxide output (CO2) determines ventilatory efficiency. During cardiopulmonary exercise testing (CPET), ventilatory efficiency can be measured as the slope of the (VE) versus VCO2 relationship or the lowest VE/VCO2. We evaluated the test-retest reliability of these two ventilatory efficiency indices in 29 healthy subjects (14 males). Each subject performed duplicate cycle ergometer tests on different days. Ventilation and the gas fractions for oxygen and CO2 were measured with a Vacumed metabolic cart. Linear regression analysis of the VE versus VCO2 slope for the duplicate tests in the males, females, and both sexes combined yielded correlation coefficients of 0.822, 0.942, and 0.910, respectively. The corresponding correlation coefficients for the lowest VE/VCO2 were 0.745, 0.929, and 0.884. A comparison of the test-retest correlation coefficients between the two ventilatory efficiency measures for the men, women, and both sexes combined revealed that they were not significantly different and, for a given index, there were no sex differences. The bias (mean of difference scores between tests) and 95% limits of agreement for the VE versus VCO2 slope in the males, females, and both sexes combined were -0.05 +/- 2.41, -0.57 +/- 1.92, and -0.32 +/- 2.20, respectively. The bias and 95% limits of agreement for the lowest VE/VCO2 were very similar with values of 0.06 +/- 2.45, -0.22 +/- 2.03, and -0.10 +/- 2.27. We conclude that the test-retest reliability for the VE versus VCO2 slope and the lowest VE/VCO2 is the same and that there is no sex difference in reliability for either index of ventilatory efficiency.

Is ventilatory efficiency dependent on the speed of the exercise test protocol in healthy men and women?

Indices of ventilatory efficiency have proven useful in assessing patients with heart and lung disease. One of these indices is the slope of the ventilation (V(E)) versus carbon dioxide output (VCO(2)) relationship during cardiopulmonary exercise testing (CPET) for work rates where the relationship is linear. However, this relationship is defined not only by the slope but also by the y-intercept. To examine whether this relationship is dependent on the speed of the CPET protocol, 30 healthy subjects (16 males) were administered a rapid CPET with 1-min increment duration (1-min CPET) to the limit of tolerance and a slow CPET with 4-min increment duration (4-min CPET) to the lactate threshold. Ventilation and the gas fractions for oxygen and CO(2) were measured with a Vacumed metabolic cart. The average increment size of both protocols for both sexes was not significantly different (P>0.05). For the males, the mean (SD) slope for the 1- and 4-min CPET was 20.12 (2.61) and 20.37 (2.41), respectively. The corresponding values for the y-intercept were 4..89 (2.08) and 5..10 (2.00) l min(-1). For the females, the mean (SD) slope for the 1- and 4-min CPET was 23.90 (2.38) and 24.16 (2.55), respectively. The corresponding values for the y-intercept were 3.93 (0.39) and 3.77 (0.71) l min(-1). Paired t-test analysis demonstrated for both sexes that the slopes and y-intercepts were not different for the two protocols (P>0.05). The results of this study demonstrate that the V(E) versus VCO(2) relationship is not dependent on the speed of the CPET protocol.

Exercise test mode dependency for ventilatory efficiency in women but not men.

Ventilatory efficiency is commonly defined as the level of ventilation V(E) at a given carbon dioxide output (V(CO(2) )). The slope of the V(E) versus V(CO(2) ) relationship and the lowest V(E)/V(CO(2) ) are two ventilatory efficiency indices that can be measured during cardiopulmonary exercise testing (CPET). A possible CPET mode dependency for these indices was evaluated in healthy men and women. Also evaluated was the relationship between these two indices as, in theory, V(E)/V(CO(2) ) falls hyperbolically towards an asymptote that numerically equals the V(E) versus V(CO(2) ) slope at exercise levels below the ones that cause respiratory compensation for metabolic acidosis. Twenty-eight healthy subjects (14 men) underwent treadmill and cycle ergometer CPET on different days. Ventilation and the gas fractions for oxygen and CO(2) were measured with a vacumed metabolic cart. In men, paired t-test analysis failed to find a mode difference for either ventilatory efficiency index but the opposite was true in the women as each woman had higher values for both indices on the treadmill. For men, the lowest V(E)/V(CO(2) ) was larger than the V(E) versus V(CO(2) ) slope by 1.3 on the treadmill and 0.8 on the cycle ergometer. The corresponding values for women were 1.7 and 1.4. We conclude that in healthy subjects, women, but not men, demonstrate a mode dependency for the two ventilatory efficiency indices investigated in this study. Furthermore, our results are consistent with the theoretical expectation that the lowest V(E)/V(CO(2) ) has a numerical value just above the asymptote of the V(E)/V(CO(2) ) versus V(CO(2) ) relationship.

DIASTEMA INTERINCISIVO CENTRAL SUPERIOR

La práctica de la Odontología debe estar siempre en manos del profesional odontólogo y que él por lo tanto debe ser capaz de brindar ese servicio, conocer la presencia del hueso premaxilar y la influencia de la sutura en la línea media como nueva causa para la presencia del diastema interincisivo central superior, prvocando un espacio antómico entre dos dientes vecinos que impide el apoyo coronario mesiodistal, cuando éstos se encuentran correctamente erupcionados y alineados formando el sector anterior del arco dentario. Lo que ha permitido precisar, como tema actual y necesario a investigar: "EL DIASTEMA INTERINCISIVO CENTRAL SUPERIOR". Sobre la base temática se determinó el siguiente: PROBLEMA: Cómo influye la fusión imperfecta en línea media de los maxilares en la etiología del diastema interincisivo central superior? OBJETO DE ESTUDIO: El sector alveolar anterior de los huesos maxilares superiores. OBJETIVO: Demostrar la presencia de fusión imperfecta en la línea media de los maxilares superiores como causa etiológica del diastema interincisivo central superior