Capnography Module for Ventilation and Monitoring Systems

Gas Analysis

Ventilated patients need to be monitored reliably. An important parameter here is the CO2 concentration in exhaled air. Accurately measuring this helps medical staff to assess the patient’s breathing and condition and supports them in their treatment. The right technology for this is: CAP201. A sophisticated and proven OEM module for capnography in emergency medicine and clinical applications. Ready to be integrated into your ventilator or monitor system.

Reliable and accurate CO2 measurement


  • Highly precise sidestream CO2 measurement
  • Calculating etCO2, fiCO2 and breathing rate
  • Occlusion detection
  • Output of a capnogram as a continuous CO2 curve


  • Compensation of temperature and aging influences without the need for recalibration
  • Low energy consumption
  • Compact design and lightweight

Capnography: Gold standard for monitoring the tube position

As well as the concentration of inhaled carbon dioxide (fiCO2), CAP201 records the maximum CO2 value at the end of the expiration phase (etCO2) and outputs it graphically as a measurement curve. This value allows conclusions to be drawn about the patient’s respiration and about the partial pressure of CO2 of the arterial blood (paCO2), determining this otherwise requires a blood gas analysis. Furthermore, etCO2 can indicate whether the tube is positioned correctly in intubated patients.

The technology

Infrared spectroscopy

CAP201 is based on non-dispersive infrared spectroscopy. CO2 molecules absorb infrared radiation of specific wavelengths. CAP201 puts this physics to use: an infrared emitter radiates through the measuring volume taken from the exhaled air. Present CO2 attenuates the infrared radiation detected by an optical detector at the end of the measuring section. The more CO2 molecules present, the weaker the measurement signal – from which the concentration can be calculated.

Sidestream CO2 measurement

The CAP201 capnography module works using the sidestream method. During this process, a pump continuously draws a small amount of the tidal air into a measuring chamber via a thin tube a thin tube attached to the ventilation hose system. The advantages:

  • Less weight on the tube means the risk of extubation failure is lower
  • No risk of infection due to external measurement without respiratory gas recirculation
  • Reliable measurement independent of contamination in the ventilation tube
  • Suitable for monitoring non-intubated patients

Compensation of influencing factors

Air pressure or temperature fluctuations inevitably lead to deviations in the signal with the measuring principle of the CAP201. The module automatically and reliably corrects these with an integrated compensation procedure. A warm-up time of less than 5 seconds ensures that the module is immediately ready to be used by first responders.

No blurriness over the lifetime, no service calibration: using a reference measurement via an additional measuring channel, the CAP201 also compensates for aging effects. They therefore rely on accurate measurements over the entire lifetime.

Areas of use

Various areas of application place different demands on the technology. Whether it’s measurement accuracy, resistance to environmental conditions, weight or flexibility in assembly – upon request, we can customize the capnography module to make it easier for you to integrate it into your technology. We offer optimized versions for common areas of application.

Optimized designs for various areas of application

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More Information
Ideal for emergency medicine and first responders

CAP201 EMERGENCY is characterized by a compact and robust design. It works reliably over a wide pressure and temperature range.

Especially designed for use in clinics

CAP201 CLINIC is designed for clinical applications with a high measurement accuracy.

For use in an MRI setting

CAP201 MRI is designed with non-magnetic components. Thus, it can be used in magnetic fields of 1.5 to 3 Tesla. The measurement signal of the CAP201 is not affected even by strong high-frequency gradients.

The most important technical data of the CAP201

  • Compact design: 70 x 40 x 26 mm
  • Lightweight: 69 g (including pump)
  • Variable supply voltage: 3.3 to 7.2 V
  • Low power consumption: ~ 1W

 Download product sheet

Test the integration for yourself

With a CAP201 Development Kit

Do you want to find out how well the CAP201 fits into your system? Would you like to integrate the module on a trial basis? Do you want to check the interface connection and weigh up assembly options? Then our Development Kit is the right choice for you. The following are included:

  • CAP201 module, optionally emergency, clinic or MRI version
  • CAP201 pump set
  • Accessories for testing and commissioning
  • Driver and software for controlling the CAP201
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