Impact of Patient Throughput in CT Suite on Iodinated Contrast Media (ICM) Waste Using Multidose Injectors

Purpose: Multidose injectors have shown promise in reducing ICM waste. However, the impact of patient volume variations on total ICM use and waste in multidose versus single-dose injectors remains underexplored. This study investigates how changes in patient throughput affect ICM use and waste in multidose injectors.

Methods/Materials: We retrospectively evaluated per-patient contrast usage for all contrast enhanced CT studies at our emergency department for a one-year period. The amount of contrast waste was calculated for single dose injector when 100 mL bottle of contrast was used. ICM use in multidose syringeless injector for the same patient population using 1,000 mL contrast container which can be used for 8 hours was measured using a simulation model. The amount of total contrast use and contrast waste was calculated. To investigate the effect of patient throughput, the model was further modified to generate new datasets with lower and higher patient volumes using a baseline average ED CT patient volume of 2.5 per hour. ICM use and waste was calculated for the 1,000 mL multidose injector using these patient volumes.

Results: New simulated patient throughputs (patient/hour) were: 0.8[0.5-0.9], 1[1.2-1.5], 1.8[1.7-1.9], 3.5[3.2-3.9], 4.8 [4-5.5]. Throughput was categorized as: < 1, 1-1.5, 1.5-2, 2-3, 3-4, and >4 patients/hour. Total ICM use and waste were significantly reduced in settings with more than 2 patient per hour (2-3: (22.3%), 3-4: (52.7%), >4: 42.5%). Conversely, in lower patient volumes, less than 2 patient per hour, the ICM use was significantly higher in multidose injectors ( < 1: (250%), 1-1.5: (81.6%), 1.5-2: (15.8%) due to residual unused contrast.

Conclusions: High patient volume settings can lead to considerable ICM savings by using multidose injectors. In contrast, lower patient throughput does not yield efficient ICM usage and waste reduction with these injectors.