Device for measuring energy metabolism in animals using indirect calorimetry
The device addresses the lack of automated calculations in existing devices by using sensors and a microcontroller to measure oxygen and carbon dioxide, dynamically assessing animal physiology factors, achieving precise metabolic analysis.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- FEDERALNOE GOSUDARSTVENNOE BYUDZHETNOE NAUCHNOE UCHREZHDENIE FEDERALNYJ ISSLEDOVATELSKIJ TSENTR KRASNOYARSKIJ NAUCHNYJ TSENTR SIBIRSKOGO OTDELENIYA ROSSIJSKOJ AKADI NAUK
- Filing Date
- 2025-11-27
- Publication Date
- 2026-07-01
AI Technical Summary
Existing devices for measuring gas exchange in animals lack automated calculation of consumed oxygen and emitted carbon dioxide, calculation of the respiratory quotient, and the ability to dynamically assess factors affecting animal physiology such as pressure, temperature, oxygen concentration, and carbon dioxide concentration.
A device incorporating a peristaltic pump, sensor unit with pressure, temperature, and carbon dioxide sensors, connected to a microcontroller, which calculates and records oxygen consumption, carbon dioxide emission, and respiratory quotient, while compensating for pressure changes using an oxygen generator, allowing dynamic assessment of physiological factors.
Accurately calculates carbon dioxide emission and oxygen consumption, and determines the respiratory quotient, providing insights into animal metabolism and physiological factors like temperature and pressure.
Smart Images
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Abstract
Description
[0001] This invention relates to medical technology (veterinary, scientific) for measuring gas exchange and assessing the intensity of overall metabolism in animals. It comprises a measuring chamber, a pump for pumping a gas medium, a carbon dioxide absorber, an oxygen generator, temperature, pressure, oxygen, and carbon dioxide sensors, and is intended for studying gas exchange as an indicator characterizing metabolic processes in animals. The device can be used in specialized scientific institutions.
[0002] A device is known for determining the oxygen consumption of living organisms [RU 94009088 A, published 05 / 20 / 1996], consisting of a chamber with trays and a shutter, divided into two sections, one of which is a section with a carbon dioxide absorber, and the second section is a living section, and a unit for automatic measurement of consumed oxygen with a sensitive sensor (displacement meter) and a digital visual report with an output to a computer.
[0003] Also known is a device [Author's Certificate SU 1487864, published 23.06.1989, IPC A61B5 / 08], consisting of a sealed container with an animal, in the lower part of which there is a section with a carbon dioxide absorber, and the container with the animal is connected through a tee to a pressure gauge for monitoring the pressure in the container and to an oxygen reservoir with graduations.
[0004] The closest analogue is a device for measuring oxygen consumption by laboratory animals [SU 1591953, published 15.09.1990, IPC A61B5 / 08], which includes a measuring, oxygen, and pressure chamber, a burette, a water pressure gauge, a float valve, and a carbon dioxide absorber.
[0005] The main disadvantages of the listed devices are the lack of automated calculation of consumed oxygen and emitted carbon dioxide, as well as the calculation of the respiratory quotient as an indicator of energy exchange, the need for pure oxygen, the inability to assess factors affecting the physiology of the animal in dynamics, such as pressure, temperature, oxygen concentration and carbon dioxide concentration in the measuring chamber.
[0006] The technical result of this invention is the creation of a device for measuring energy exchange using indirect calorimetry with the ability to dynamically evaluate factors affecting the physiology of an animal, such as pressure, temperature, oxygen concentration and carbon dioxide concentration inside the measuring chamber, with automated calculation of the volume of released carbon dioxide, the volume of oxygen absorbed by the animal per unit of time, and with the calculation of the respiratory quotient.
[0007] The technical result is achieved due to the fact that in the device for measuring energy exchange by the method of indirect calorimetry in animals, including a measuring chamber and a carbon dioxide absorber, what is new is that the device contains a peristaltic pump that takes air from the measuring chamber and pumps it into the sensor unit, the sensor unit includes a pressure sensor, a temperature sensor, oxygen concentration sensors and carbon dioxide concentration sensors, while the sensor unit is connected to the carbon dioxide absorber, which is connected to the measuring chamber, while the pressure sensor is connected via a feedback system to an oxygen generator, which is connected to the measuring chamber, while the oxygen generator, peristaltic pump and sensor unit are connected to a microcontroller that sends data from the sensors, as well as automatically calculated indicators of absorbed oxygen,the released carbon dioxide and the respiratory quotient as an indicator of energy exchange to the computer for recording in a file at selected intervals.
[0008] A comparative analysis with the prototype shows that the claimed device features a peristaltic pump, a sensor unit including a pressure sensor, a temperature sensor, oxygen concentration and carbon dioxide concentration sensors, and a carbon dioxide absorber connected to a measuring chamber. The pressure sensor is linked via a feedback system to an oxygen generator, which is connected to the measuring chamber. The oxygen generator, peristaltic pump, and sensor unit are connected to a microcontroller, which sends sensor data, as well as automatically calculated values of oxygen absorption, carbon dioxide emission, and the respiratory quotient as an indicator of energy exchange, to a computer for recording at selected intervals.
[0009] These distinctive features, in combination with other features, ensure a positive effect, consisting of a highly accurate automated calculation of the volume of carbon dioxide emitted by the animal and the volume of oxygen consumed, as well as the calculation of the respiratory quotient as a marker of the intensity of general metabolism in animals, as well as obtaining information on factors affecting the physiology of the animal, such as temperature, pressure, and the concentration of carbon dioxide and oxygen inside the measuring chamber in dynamics.
[0010] The invention is explained by the following figures: Fig. 1 shows a diagram of the device; Fig. 2 is a graph of the dynamics of oxygen consumption by an animal; Fig. 3 is a graph of the dynamics of carbon dioxide release by an animal; Fig. 4 is a graph of the dynamics of the respiratory quotient.
[0011] The claimed device consists of a measuring chamber (1) connected to a peristaltic pump (2), which in turn is connected to a sensor unit (3), and the sensor unit (3) is connected to a carbon dioxide absorber (4), which is connected to the measuring chamber (1), while an oxygen generator (5) is connected to the measuring chamber (1), and while the oxygen generator (5), peristaltic pump (2) and sensor unit (3) are connected to a microcontroller (6).
[0012] The claimed device operates as follows: an animal is placed in the measuring chamber (1) and sealed hermetically, air is taken from the measuring chamber (1) by means of a peristaltic pump (2) and enters the sensor unit (3), where it passes through a pressure sensor, a temperature sensor, an oxygen sensor, a carbon dioxide sensor, and the information from the sensors is sent to the microcontroller (6), where, based on the concentration of carbon dioxide in the measuring chamber (1), under the condition of a constant system volume and a constant air flow rate, the volume of carbon dioxide released by the animal per unit of time is calculated, then the air passes through a carbon dioxide absorber (4), and, purified from carbon dioxide, enters back into the measuring chamber (1), while as a result of oxygen consumption by the animal and the absorption of carbon dioxide by the carbon dioxide absorber, a pressure drop occurs, which is recorded in the sensor unit (3) by a pressure sensor,which is connected via a feedback system to the oxygen generator (5), and oxygen is generated, compensating for the pressure drop. The microcontroller (6) records the operating time of the oxygen generator (5), which, taking into account Faraday's law, allows:
[0013] V(O2) = (I * t * 22.4) / 4*96485,
[0014] where I is the electrolyzer current (2 A), t is the operating time of the oxygen generator (5)
[0015] Convert the oxygen generator's operating time (5) to milliliters of oxygen generated per unit of time. The microcontroller (6) sends calculated data on the volume of oxygen consumed and carbon dioxide emitted, as well as the animal's current respiratory quotient, as well as factors affecting the animal's physiological state, such as temperature, pressure, and the concentration of carbon dioxide and oxygen inside the measuring chamber (1) via the COM port to the computer for recording to a file at selected intervals.
[0016] Example of device operation
[0017] A 30-gram mouse is placed in the measuring chamber, and the measuring chamber is closed. The device is switched to the measurement mode, air is drawn from the measuring chamber by a peristaltic pump and supplied to the sensor unit, where it passes through pressure, temperature, oxygen concentration, and carbon dioxide concentration sensors. The air then passes through a carbon dioxide absorber, where carbon dioxide is absorbed, and is pumped back into the measuring chamber. At the same time, the oxygen generator, connected via a feedback system to the pressure sensor, supplies oxygen to the measuring chamber when the pressure drops as a result of the animal's oxygen consumption and the absorption of carbon dioxide by the carbon dioxide absorber, compensating for the pressure drop. The microcontroller sends calculated data on oxygen consumption (Fig. 2) and carbon dioxide release (Fig. 3), as well as the current respiratory quotient (Fig.4) in the animal, as well as data on factors influencing the physiological state of the animal, such as temperature, pressure, and concentration of carbon dioxide and oxygen inside the measuring chamber via the COM port to a computer for recording in a file at selected intervals (Table 1). The data on oxygen consumption and carbon dioxide release obtained using this device are in good agreement with the research data [Some indicators of basal metabolism in mice of different lines / E. A. Sheiko, I. V. Kaplieva, N. S. Lesovaya [et al.] / / Laboratory animals for scientific research. - 2025. - No. 1. - P. 65-71. - DOI 10.57034 / 2618723X-2025-01-04. - EDN RUPJQY.].
[0018] Example of writing to a file
[0019] Table 1
[0020] Time, min Pressure, kPa Temperature, °C CO2 level, ppm Released CO2, ml / min O2 level, % O2 consumed, ml Respiratory quotient 1 98,66 26,20 8717,4 1,91 21,45 2,12 0,90 2 98,92 26,20 8707,2 1,90 21,41 2,13 0,89 3 98,69 26,19 8689,8 1,90 21,25 2,46 0,77 4 98,54 26,22 8193,9 1,81 21,98 2,20 0,82 5 98,78 26,20 8256,0 1,82 21,79 2,29 0,80 6 98,92 26,23 9271,5 2,00 21,92 2,20 0,91 7 98,73 26,22 9083,4 1,97 21,82 2,04 0,97
Claims
A device for measuring energy exchange in animals by indirect calorimetry, comprising a measuring chamber and a carbon dioxide absorber, characterized in that it contains a peristaltic pump configured to draw air from the measuring chamber and pump it into a sensor unit, which includes a pressure sensor, a temperature sensor, oxygen concentration sensors and carbon dioxide concentration sensors, wherein the sensor unit is connected to the carbon dioxide absorber, which is connected to the measuring chamber, wherein the pressure sensor is connected via a feedback system to an oxygen generator, which is connected to the measuring chamber, wherein the oxygen generator, the peristaltic pump and the sensor unit are connected to a microcontroller configured to send data from the sensors, as well as automatically calculated indicators of absorbed oxygen,the released carbon dioxide and the respiratory quotient as an indicator of energy exchange to the computer for recording in a file at selected intervals.