Columbus Instruments Micro-CapnoGraph CI240 monitor has the most outstanding features of any monitor available. Capabilities include microprocessor control, waveform display, digital calibration, multiple alarms, and more.The CI240 has many advanced features which make it an excellent choice for both intubated or non-intubated small animals like rats and mice. At the heart of this system is the internal fast response CO2\N2O gas analyzer and state of the art pressure and pneumatics control system which utilizes a very low sample flow rate (5 mL\minute to 20 mL\minute).The CI240 uses three microprocessors to distribute the processing requirements of its unique features. The CI240 optionally interfaces via RS232 serial output to a personal computer (PC) and via analog output for interfacing with a data acquisition system or chart recorder device. (Optional MCGWIN software for capturing and displaying the trend data is available)The CI240 is unique in its capability of providing accurate measurements of CO2 and N2O concentration and Respiration rate at very low sample flow rate with a standard Nondispersive Infrared (NDIR) gas sensor. The CI240 operates at low pressure, using a heavy-duty air pump and digital closed loop pressure control system.This design maintains the sample cell pressure and sample flow rate constant at the desired reference pressure. The CI240 draws a sample of gas through the sample cell. It uses an Infrared light source, optical band pass filter and detector to measure the amount of CO2 in the sample. The sample can be read as a partial pressure in mmHg or as a volume in percentage and the amount of N2O as a volume in percentage.The continuous waveform is used to calculate the respiration rate in breath per minute (BPM) and to find the End tidal value of CO2 (ETCO2) and the Base line value of CO2 (BLCO2) on a breath-by-breath basis. ETCO2, BLCO2 and RESR are displayed as an average of 1, 4 or 8 (user selectable) breaths updated every breath. The Inspired N2O (INSP N2O) is displayed continuously.