Description
Indirect calorimetry is a non-invasive and accurate method to determine substrate utilisation and metabolic rate indirectly, by measuring the production of carbon dioxide (CO2) and the consumption of oxygen (O2). From these gas exchange measurements, type and rate of substrate utilisation can be assessed. The MAX-II metabolic cart enables indirect calorimetry in humans under resting conditions (by using a ventilated hood, bed available) and exercise conditions (by using a face mask, bicycle ergometer available).
Technical Details
• Paramagnetic Oxygen Analyzer
(Accuracy: ± 0.03% O2 over 10 – 21% O2 range, repeatability: ± 0.03% O2, resolution: Digital Display ± 0.01 % O2, Operating Range: 0 – 100% O2).
• Infrared Carbon Dioxide Analyzer
(Accuracy: ± 0.03% CO2 over 0 – 7% CO2 range, Repeatability: ± 0.03% CO2, Resolution: Digital Display ± 0.01% of CO2, Operating Range: 0 – 10% CO2).
• Pneumotach Breath Volume Measurement System
(Flow Range: 0 to greater than 800 liters/minute, Volume Accuracy: better than ± 1.0%, Resistance to Flow: 2.8 cm H2O at 400 liters/min).
• Sample Pump and Flow Controller.
• Heart Rate Interface with Polar monitor.
• Real time continuous Temperature, Humidity & Pressure Monitoring
(Temperature: ± 0.5 °C, Pressure: ± 1 mmHg, Humidity: ± 3% RH).
Applications
Measurement of resting metabolic rate: using the canopy mode of the MAX-II, resting metabolic rate (RMR) can be measured in a comfortable supine position. RMR can be used to estimate 24-hour caloric requirements and can measure substrate utilisation as reflected by the respiratory quotient.
Activity-associated energy expenditure: By combining breath by breath analysis and physical activity, energy expenditure can be calculated at a given work load. The volume of inhaled gas is measured using a flow meter and exhaled air is sampled for measurement of O2 consumption and CO2 production.
Complementary Techniques
• Canopy system for measurement of basal metabolic rate.
• Lode bicycle ergometer to combine metabolic measurement with physical activity.
• Mask kits for comfortable exercise testing.
• Kitchen utilities to measure energy expenditure in response to a meal.