OxiCarbo®, a single sensor for the non-invasive measurement of arterial oxygen saturation and CO2 partial pressure at the ear lobe

The paper describes the characteristics and results obtained in adults with a new miniaturised sensor combining the measurement of arterial oxygen saturation by optical means and arterial P-CO2 by electrochemical means (OxiCarbo (R) sensor). The sensor is heated to 42 degreesC to create arterialisation of the cutaneous tissue and is applied to the ear lobe with a special low-pressure clip. The use of the sensor heating significantly improves the performance of the Sp(O2) measurement. The heating increases the arterial pulsation signal and decreases the non-arterialised tissue signal. The fluctuations of the measurement are reduced. The quantitative results of the Sp(O2) measurements are not affected by the heating. The measurement at the ear lobe improves also the P-CO2 measurement by decreasing the arterialisation time from approximately 7 min at the forearm to less than 3 min at the ear lobe. At a temperature of 42 degreesC, the sensor may be left at the same central site for over 12 h without the risk of a skin burn. (C) 2001 Elsevier Science B.V. All rights reserved.