MM-100
Metabolic Monitor System for VO2 & CO2
The MM-100 Metabolic Monitor
System measures oxygen consumption (VO2) and CO2 production
(VCO2) of small animals using the open circuit technique.
The animal is placed in a closed chamber with a known flow
of fresh air passing through it. Oxygen and carbon dioxide
concentrations are measured at the inlet and outlet of
the chamber. The three measurements (flow, O2, and CO2)
enable the computation of oxygen consumption, CO2 production,
and Respiratory Exchange Ratio (RER), or VCO2/VO2. The
keys to accurate O2 consumption measurement are the sensors.
The MM-100 uses the latest generation of highly accurate
and stable gas and flow sensors. Flow is monitored by a
solid-state thermal mass flowmeter. Oxygen is measured
by a high-resolution paramagnetic O2 sensor. CO2 measurement
uses a special lowrange infrared analyzer cell. The system
automatically calibrates itself against ambient room air,
so the key differential gas measurements are always accurate.
The system can monitor one or several animals. In its basic
configuration, the MM-100 will make measurements on a single
animal without requiring any additional components. Multiple
cages can be added using economical expansion modules.
The expansion modules are available in two or four-cage
units. The MM-100 communicates with and controls the expansion
modules; cage flow measurements and gas samples are routed
automatically as required.
- End-tidal
peak or continuous readings
- Low sample
flow requirements
- Accurate
and stable monitoring
- Linear output
signal for recording
- Respiratory
monitoring
- Use with
ventilated or unassisted animals
- Suitable
for rats and larger animals
- CO2 control
with AVS-1 Ventilator
External control
and measurement
The measurements and computed results are reported directly on the front-panel
LCD display. In addition, the three critical variables, flow, O2, and CO2, are
output as analog voltages for external monitoring and computation using standard
PC-based data acquisition. The necessary equations are provided for the user
to compute all the relevant measurements. An alternative means of PC communication
is also provided: the three variables, along with cage ID and other information,
are automatically output to a standard serial port. The data is configured so
that it can be received using any communications software, and easily imported
into a spreadsheet for calculation. When using a multi-cage system, a simple
digital logic interface is provided to select a specific cage for measurement.
This control interface typically uses the digital I/O available on most data
acquisition boards, or, if that is not present, a parallel printer port can be
used. When this external control is in use, the cage ID is displayed on the LCD
panel, showing at a glance which animal is being monitored.
Operation
Operation of the system is fully automatic. The animal is placed in the chamber
and allowed to become accustomed to the environment. Once the gasses are
equilibrated, a reading is taken of O2 consumption and CO2 production.
With the multi cage expansion in use, the gas sampling is automatically
sequenced, and the results are displayed. The only consumable material
is the drying agent used to condition the gas samples.
Measures:
O2 consumption (VO2)
CO2 production (VCO2)
Standard Features:
Paramagnetic O2 analyzer
Infrared CO2 analyzer
Solid-state mass flow meter
Display of measurements & computed values
No additional equipment required for one animal
