Continuous intravascular blood gas monitoring: development,current techniques,and clinical use of a commercial device

This review focuses on the development, current techniques,and clinical use of continuous intravascular blood gas monitoring(CIBM) devices in anaesthesia and intensive care. The operatingprinciples, range of application, performance, limitations,costs, and impact on patient treatment and outcome, are discussed.Studies of early and currently available CIBM devices were analysed.At present, the Paratrend 7+^® (PT7+^®) for adults andNeotrend^TM (NT^TM) for newborns are the only commercially availableCIBM systems. The PT7+^® contains three optical sensors tomeasure PO₂, PCO₂ and pH, as well as a thermocouple to measuretemperature. The NT^TM is a modification of the PT7+^® tocontinuously monitor PO₂, PCO₂, pH and temperature in newborns.Under laboratory conditions, good performance over a wide rangeof blood gas values was observed with the Paratrend 7^® (PT7^®).Performance in the clinical setting was not as satisfactory,especially for PO₂ values. However, the performance and accuracyof CIBM devices appear to be sufficient for clinical use andthey are being used clinically in selected patient groups. Severalfactors affecting the performance of CIBM are considered. Br J Anaesth 2003: 91; 397–407