A new device to limit extravasation during contrast-enhanced CT

OBJECTIVE. The extravasation detection accessory (EDA) is designed for use during contrast-enhanced CT studies performed with a power injector. The ED A detects the changes in soft-tissue impedance that occur with enhanced ext ravasation and halts the further infusion of contrast material via a feedba ck circuit to the injector. We tested the sensitivity of this device in a m odel of contrast extravasation. MATERIALS AND METHODS. Study subjects had an extravasation of 5% dextrose i n water (nonionic contrast equivalent) in one arm and 0.9% sodium chloride solution (ionic contrast equivalent) in the other. An EDA was placed over t he site of infusion and connected to a power injector. Injections were perf ormed at 0.25 ml/sec (n = 40), 2.5 ml/sec (n = 62), or 5 ml/sec (n = 20). RESULTS. At infusion rates of 2.5 and 5 ml/sec, the device halted the injec tor in every subject after an average volume of 12.5 +/- 1.6 ml was deliver ed. At 0.25 ml/sec, the device failed to halt the injector in 11 of 20 even ts. After reprogramming the algorithm, 10 more subjects were tested at the lowest injection rate. The device halted 18 of 20 extravasation events with an average volume of 3.7 +/- 0.5 ml. CONCLUSION. In our model of contrast extravasation, the EDA halted a power injector with reliability and reproducibility before a large volume of cont rast material was delivered. The sensitivity of the device approached, but did not reach, 100%. This device may serve to diminish the morbidity of ext ravasation events.