Original Article

An Investigation of the Bentley^R Gas-STAT^TM Monitoring System GSM-100

Dept. of Anaesthesia, Dept. of Cardiothoracic Surgery Rigshospitalet, Copenhagen, Denmark

^* Direct Communications to: Kaj Gefke, M.D., Department of Anaesthesia, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.

Abstract

(J. Extra-Corpor. Technol. 20(2):59-62) The Bentley^R Gas-STAT™ monitoring system GSM-1 00 (GSM) is an optical fluoroscence microsensing system with a sensor placed in the extracorporeal circuit. It measures blood temperature and analyses oxygen tension, carbon dioxide tension, and pH at the actual blood temperature, and the results may be converted to values at 37°C.

In 6 pigs subjected to cardiopulmonary bypass at 28°C and 37°C, this system was compared to the Radiometer Acid-Base Laboratory-2 blood gas analyser (ABL-2). A total of 102 blood samples were drawn from the arterial and venous lines of the circuit next to the GSM sensors, and simultaneously the GSM readings were recorded. The samples were analyzed by the ABL-2 at 37°C, and the results were converted to the actual temperature by the apparatus.

Statistical evaluation was performed by a linear regression model of ABL-2 readings on GSM readings. From preliminary analyses of the results, it appeared that for each of the three parameters all the data might be pooled into one regression.

The results indicated that the agreement between ABL-2 readings and GSM readings with respect to pO₂ and pCO₂ were only fair though not clinically acceptable. The correlation between GSM readings and ABL-2 readings of pH were poor and the GSM readings without clinical relevance.