Validity of the Vyntus CPX Metabolic Cart for Assessing Postprandial Energy Expenditure and Respiratory Exchange Ratio
试验速览
- 阶段
- 不适用
- 入组人数
- 12
- 试验地点
- 1
- 主要终点
- VO2 post-prandial gas exchange assessed by indirect calorimetry
研究概览
简要总结
The aims of the present study are described below:
Aim 1: In-vitro measures to determine the validity, precision and accuracy of the Vyntus CPX metabolic cart assessed by:
1.1. Methanol burning tests. 1.2. Pure gas (nitrogen [N2] and carbon dioxide [CO2]) infusions to simulate both, constant and variable fluxes of oxygen consumption (VO2) and carbon dioxide production (VCO2) in different conditions and moments.
- Immediately after or prior the methanol burning test (in a randomized order).
- In separate days and time-periods.
Aim 2: In-vivo measures using the Vyntus CPX metabolic cart:
2.1. To assess the resting metabolic rate (RMR or resting energy expenditure [REE]) and respiratory exchange ratio (RER) day-to-day biological reproducibility (i.e. reliability) of the metabolic cart.
2.2. Further, the investigators will use an oral glucose tolerance test (OGTT) to determine the post-prandial day-to-day biological reproducibility (especifically the post-prandial RER) of the metabolic cart.
详细描述
The study will be developed in three different experiments which are detailed below:
EXPERIMENT 1 (AIM 1.1 AND 1.2.A):
The investigators will determine the Vyntus CPX measurement error over 14 different days by using both, methanol burnings and pure gas infusions. The order will be random.
- Methanol burning: the investigators will burn the methanol inside the glass-cage and the investigators will measure dynamically the weight of burned alcohol; gas exchange will be continuously measured with the Vyntus CPX while the produced gases are directed into the metabolic cart's hose tube. The burning will take approximately 25-30 minutes and is expected to produce a RER=0.667.
- Pure gas infusions: Pure N2 (concentration ≥99.9997%) for diluting ambient O2 and CO2 (concentration ≥99.995%) will be infused using high-precision mass-flow controllers (358 Series, Analyt-MTC, Müllheim, Germany; 0-2 l/min) into the metabolic cart's hose tube. The infused volumes of N2 and CO2 will be selected to replicate (i.e. mimic) as much as possible the VO2 and VCO2 produced by the methanol burning test. The gas infusions will last 20 minutes.
EXPERIMENT 2 (AIM 1.2.B):
研究设计
- 研究类型
- Observational
- 观察模型
- Other
- 时间视角
- Other
入排标准
- 年龄范围
- 18 Years 至 40 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Age 18-40 y.
- •BMI between 18.5 kg/m2 and 30 kg/m2 (both inclusive).
- •Willing to fast and not to consume non-caloric stimulant for 12h before the assessments.
- •Willing to avoid moderate or vigorous physical activity during 24-48h respectively.
- •Have a stable body weight over the last 3 months (changes ≤3 kg) and not being enrolled in a weight loss program.
排除标准
- •Smoking or use of tobacco products within the last 3 months.
- •Diagnosed with diabetes.
- •Previous bariatric surgery (or other surgeries) for obesity or weight loss.
- •Use of medications affecting metabolism or sleep.
- •History of neurological disease.
- •History of cardiovascular disease, including hypertension, or other chronic diseases.
- •Pregnant, planning to become pregnant, or breastfeeding.
- •Adherence to special restrained diets (e.g., low-carbohydrates, low-fat, or vegetarian/vegan diets) over the last 3 months.
- •Claustrophobia impeding to stay calm under a plastic canopy.
结局指标
主要结局
VO2 post-prandial gas exchange assessed by indirect calorimetry
时间窗: 5 hours
Volume of oxygen consumption (VO2 \[ml/min\])
VCO2 post-prandial gas exchange assessed by indirect calorimetry
时间窗: 5 hours
Volume of carbon dioxide production (VCO2 \[ml/min\])
VO2 validity of the metabolic cart. In-vitro measurements and/or simulations to determine the validity, precision and accuracy of the metabolic cart assessed by methanol burning tests and controlled pure gas infusions.
时间窗: 14 separate days; measurements of 2 hours per day
Volume of oxygen consumption (VO2) measurement error (ml/min)
CHOox post-prandial gas exchange assessed by indirect calorimetry
时间窗: 5 hours
Carbohydrate oxidation (CHOox \[g/min\])
EE post-prandial gas exchange assessed by indirect calorimetry
时间窗: 5 hours
-Energy Expenditure (EE \[kcal/day\])
VCO2 validity of the metabolic cart. In-vitro measurements and/or simulations to determine the validity, precision and accuracy of the metabolic cart assessed by methanol burning tests and controlled pure gas infusions.
时间窗: 14 separate days; measurements of 2 hours per day
Volume of carbon dioxide production (VCO2) measurement error (ml/min)
EE validity of the metabolic cart. In-vitro measurements and/or simulations to determine the validity, precision and accuracy of the metabolic cart assessed by methanol burning tests and controlled pure gas infusions.
时间窗: 14 separate days; measurements of 2 hours per day
Energy Expenditure (EE) measurement error (kcal/day)
RER post-prandial gas exchange assessed by indirect calorimetry
时间窗: 5 hours
Respiratory Exchange Ratio (RER \[calculated as VCO2-to-VO2 ratio\])
FATox post-prandial gas exchange assessed by indirect calorimetry
时间窗: 5 hours
Fat oxidation (FATox \[g/min\])
RER validity of the metabolic cart. In-vitro measurements and/or simulations to determine the validity, precision and accuracy of the metabolic cart assessed by methanol burning tests and controlled pure gas infusions.
时间窗: 14 separate days; measurements of 2 hours per day
Respiratory Exchange Ratio (RER) measurement error
次要结局
- Anthropometric measurements 1, weight(1 day)
- Anthropometric measurements 2, height(1 day)
- Anthropometric measurements 3, body mass index(1 day)
- Post-prandial blood glucose concentrations(5 hours)
- Body composition outcomes (DXA scann)(1 day)
研究者
Jonatan Ruiz Ruiz
Principal Investigator
Universidad de Granada