THE APPLICATION OF A NONIMAGING NUCLEAR PROBE SYSTEM TO THE CRITICALLY ILL - LABORATORY VALIDATION AND A CLINICAL-TRIAL

Non-imaging nuclear probe systems have been available for bedside moni toring of left ventricular function since the early 1970s. The purpose of this study was to evaluate a recently developed system, the Cardio scint (Oakfield Instruments, Oxford, UK), both in the laboratory and c linically prior to its application in the critically ill on the intens ive care unit. The probe system was stable at body temperature for pro longed periods and its count rate capability was adequate for those en countered clinically. An adequate period of data acquisition was shown to be important because random isotope decay produces a significant n oise at these count rates. Left ventricular ejection fraction in patie nts with symmetrical ventricular contraction agree closely with the re sults obtained with radionuclide ventriculography (mean difference = 0 .98%, S.D. = 2.8%, n = 30). However, in patients with asymmetrical ven tricular contraction the agreement is poor (mean difference = -3.0%, S .D. = 6.2%, n = 10).