“Continuous Monitoring of Gastric Carbon Dioxide with Optical Fibres"


COMOCADOF is an European research project with the objective of developing an optical fibre sensor for the continuous monitoring of the partial pressure of carbon dioxide in the stomach.

Role: Coordinator

Activity period: 1996-2000

Research Line: Biphotonic Diagnostics


An optical fibre sensor for the continuous monitoring of gastric carbon dioxide was developed, based on the utilisation of a sensing layer, in which the colour of the layer is dependent on the CO2 concentration. The CO2-sensitive layer consists basically of a dye/quaternary ammonium ion pair, dissolved in a thin layer of ethylcellulose.

The sensor was thoroughly characterised in laboratory and its performances were compared with those of Tonocap, the instrument based on gastric tonometry, which is the present method for detecting partial pressure of gastric carbon dioxide. Its measurement range, 0–150 h Pa, its accuracy, 2.5 h Pa, and its response time, less than 1 min, were capable of satisfying the physicians’ requirements for clinical application. The clinical tests performed carried out on volunteers and on intensive care patients showed that the sensor developed is definitely superior to the sensor that is at presentavailable on the market (Tonocap). Because of its short response time, the optical fibre sensor is able to detect rapid changes in pCO2, which Tonocap is unable to detect.



Research Team




Main Achievement






  • project coordinator

  • design and development of the optoelectronic unit

  • development and manufacture of the fibre optic catheter

  • compliance with the European Medical Device Directive





  • development, realisation and laboratory characterisation of the sensor

  • PC software developer



Joanneum Research



  • chemistry of the sensing membrane

  • development and fabrication of the sensing membrane

  • in vitro characterisation of the probe


Karl Franzens University Medizinische Universitatsklinik



  • laboratory and clinical tests


University of Florence

Facoltà di Medicina e Chirurgia




  • laboratory and clinical tests