Metabolic Simulator with Mass Flow Controller
The Ultimate Laboratory Standard
Detail of Set Point Controller
Why Metabolic Calibration?
Ideally, the respiratory and metabolic variables (TV, RR, VE, VO2, VCO2) generated by the simulator should be indistinguishable from those produced by humans. The simulator produces and controls those variables very precisely. Consequently, one can test any breath-by-breath or mixing chamber metabolic measurement system with high accuracy and full confidence.
Metabolic Calibration uses the principle of mass preservation to create known VO2 and VCO2. The principle of mass preservation dictates that the chosen mass flow of CO2 and O2 remains unchanged regardless of the ventilatory dilution (i.e. the minute ventilation that delivers it into the system under calibration).
This top of the line metabolic calibration gas titration device consists of a Mass Flow Controller capable of delivering any set point flow of this gas (~21%CO2, 79%N2) within a range of 0 - 20 liters/min STPD and a Set Point Module (SPM) which enables selection of desired mass flows.
Four switch-selected cal gas flow values of approx. 4.85, 9.70, 14.55 and 19.40 correspond to approx. 1, 2, 3 and 4 liters per minute of VO2 and VCO2. (Model 17057 has addditional 5 and 6 liter settings) The exact value will depend on physical parameters, such as barometric pressure, air temperature and relative humidity. The provided O2CAL.xls spreadsheet software enable precise determination of the selected metabolic rate and the percentage error of the metabolic measurement system being calibrated.
The remaining two positions of the SPM's rotary switch correspond to a Zero flow setting and a continuous 10-turn potentiometer-operated selection of any desired mass flow within the range of 0 - 20 L/min STPD.
Metabolic Calibration accuracy is +/-1% VO2 & VCO2.
Most flow sensors are typically calibrated with a fixed volume manual syringe, but little is known about the performance of that flow sensor over the whole physiological range.
This device includes a mass flow controller to produce precise Metabolic Calibration gas mixtures to verify VO2 and VCO2. It provides highest accuracy and ease of adjustment.
So how does this affect the accuracy of your ventilation measurements (and ultimately VO2) when you have calibrated the flow sensor at some unknown manual stroke speed, then use the sensor for low-flow pediatric or resting measurements, or high flow VO2max measurements?
What this device can be used for:
Produce an exact, simulated VO2 and VCO2 to verify the overall accuracy of a metabolic measurement system and its software.
Check the accuracy of any flow / volume measurement device.
Simulate breathing at rates from 6 to 80 breaths per minute.
Check the effects of various gas mixtures on a flow sensor.
Model 17056 Stroke Volume Accuracy: +/-1/4%
Model 17057 Stroke Volume Accuracy between 600cc to 6000cc = +/- 1/2%
between 300cc and 600cc = +/- 1 to 2 %
Not recommended below 300cc
Motor speed is continuously variable from approx. 6 to 80 strokes per minute.
Digital Display: Breaths per minute
Mass and volumetric flow of calibration gas
Stroke Volume (Preset stops)
0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 liters
(Other volume settings available on special order)
#17056 Size: 12" (31cm) wide x 16" (41cm) high x 29" (74cm) long
Voltage: 110 / 220 VAC (Specify)
Weight: Approx 40 pounds (18 kg)
A Metabolic Calibration gas containing 20.9% CO2, balance N2, is required.
Included is an Excel file that allows you to make the required BTPS/STPD corrections automatically and print a calibration report.
Other possible uses of this device:
- This variable speed motor-driven calibration syringe will check the accuracy and repeatability of any flow sensor over the range from 3 to 240 L/min of VE.
- Produce any mixture of two gases and
change that mixture on-the-fly.
(Dilution formula available from VacuMed)
- Generate custom low-O2 mixtures for
simulated high altitude training.
- Quality Control of flow/volume sensing devices
If you want to
read more about Metabolic Calibration, click on "Dr. Andrew's Corner" and
check out references 1 and 2.
A., B.J. WHIPP, and K. WASSERMAN. A respiratory gas exchange simulator
for routine calibration in metabolic studies. Eur. Respir. J. 3:465-468,
2. GORE, C.J.,
P.G. CATCHESIDE, S.N. FRENCH, J.M. BENNETT, and J. LAFORGIA. Automated
VO2 max calibrator for open-circuit indirect calorimetry systems. Med.Sci.
Sports Exerc 29:1095-1103, 1997
We also offer
Metabolic Calibration of any Metabolic Measurement System in your lab.