Continuous intra-arterial blood gas monitoring during cardiopulmonary resuscitation

Abstract

Continuous intra-arterial blood gas monitoring is becoming more common in Intensive Care practice. Several trials have been undertaken to evaluate their performance in critically ill patients and varying degrees of accuracy have been reported [l-S]. No published trial to date has addressed the question of their utility in clinical practice, though there are anecdotal reports of their usefulness in various clinical situations. We report a case of a patient with a continuous intra-arterial sensor, who suffered a cardiac arrest and required cardiopulmonary resuscitation (CPR). Continuous blood gas monitoring during CPR has been reported before [6-81 using transcutaneous and transconjunctival oxygen electrodes and was shown to be useful in guiding therapy; continuous Pco2 monitoring was used in one study. To our knowledge, continuous pH monitoring during CPR has not been reported before. The Paratrend 7 (Biomedical Sensors, UK) is a multiparameter intravascular sensor for on-line, continuous measurements of pH, Pco2, PO* and temperature. It comprises an electrochemical oxygen sensor [9], optode-based Pco2 and pH sensors [lo] and a thermocouple for the determination of temperature. Preliminary evaluation of its use in Intensive Care patients and during anaesthesia has shown an acceptable level of accuracy over a wide range of pH, Pc02 and Pot measurements [ll-131.