PRELIMINARY CLINICAL-TRIAL OF AN EX-VIVO ARTERIAL BLOOD-GAS MONITOR

Purpose: The purpose of this study was to test the analytical performa nce of a new ex vivo arterial blood gas (ABG) monitor based on fiberop tic sensor technology (SensiCath; Optical Sensors, Inc., Minneapolis, MN) when operated by critical care practitioners in intensive care env ironments. Materials and Methods: Arterial blood analyses using a new ex vivo ABG monitor and standard clinical laboratory bench top analyze rs were compared according to an institutionally approved protocol. Th e subjects were adult intensive care unit (ICU) patients (n = 20) with an arterial cannula for pressure monitoring, expectation of ICU stay > 72 hours, need for greater than or equal to 2 ABG analyses per day, and written informed consent. The clinical setting was two ICUs, a sho ck trauma ICU, and a neurological ICU in a metropolitan area trauma ce nter, Results: One hundred seventy-five paired ABG analyses were obtai ned over 1,146 hours of monitor use (52 +/- 20 hours per patient). Com parison of ABG monitor and laboratory analyses of blood samples obtain ed at the time of measurement by the monitor provided the following re sults: For pH, the range of laboratory measurements was 7.197 - 7.512, accuracy (mean difference between the monitor and laboratory measurem ent) was +0.010, precision (standard deviation of the difference betwe en monitor and laboratory measurements) was +/- 0.027, and the correla tion coefficient (r) = 0.913. For PCO2, the range of laboratory measur ements was 24.5-61.5 mm Hg, accuracy was +1.4 mm Hg, precision was +/- 3.3 mm Hg, and r = 0.942. For PO2, the range of laboratory measuremen ts was 47.3 - 163.3 mm Hg, accuracy was +4.0 mm Hg, precision was +/- 7.9 mm Hg, and r = 0.970. No adverse events occurred associated with t he monitor. Conclusion: A practical ex vivo ABG monitor has been devel oped that offers accurate data and potential advantages to the critica l care practitioner and the critically ill patient over other ABG anal ysis systems: one 10-minute calibration procedure; 1-minute analysis t ime; no permanent blood removal from the patient; and a closed arteria l monitoring system, Precision performance is comparable to standard l aboratory ABG analysis. The ABG monitor offers reliability and ease of use, and the ability of the critical care practitioner (nurse, respir atory therapist, or physician) to obtain accurate ABG analyses as need ed at bedside. (C) 1997 by W.B. Saunders Company.