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

Abstract

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 operating principles, 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 and Neotrend (NT) for newborns are the only commercially available CIBM systems. The PT7+ contains three optical sensors to measure PO(2), PCO(2) and pH, as well as a thermocouple to measure temperature. The NT is a modification of the PT7+ to continuously monitor PO(2), PCO(2), pH and temperature in newborns. Under laboratory conditions, good performance over a wide range of blood gas values was observed with the Paratrend 7 (PT7. Performance in the clinical setting was not as satisfactory, especially for PO(2) values. However, the performance and accuracy of CIBM devices appear to be sufficient for clinical use and they are being used clinically in selected patient groups. Several factors affecting the performance of CIBM are considered.

Trends in Electrochemical Sensing of Blood Gases

“…However, these methods cannot replace the invasive blood gas analysis because of a number of limitations and the risk of artifacts. Typical problems are the patients' disease pattern, age, the entire health condition, etc [4,7,8]. Nevertheless, these noninvasive alternatives for the monitoring of arterial blood gases have been applied, e.g., during cardiopulmonary bypass [5].…”

Classical Respiratory Monitoring

“…Continuous intravascular monitoring of blood gases became widely available in the 1990s and has been steadily improving since then (Ganter and Zollinger 2003). This technology uses various techniques to miniaturize blood gas measurement sensors sufficiently to allow them to be imbedded in a catheter that can be placed in the radial, brachial, and femoral artery for continuous monitoring.…”

In Vivo Chemical Sensors: Tackling Biocompatibility

“…An outer coating of immobilized heparin was used in an attempt to reduce clot formation (30 -32). However, even with this coating, erratic clinical results were reported, and frequent one-point calibrations of the sensor were required (33,34 ).…”