Background and objective: We measured the physical performance error of commercial syringe pumps incorporating the Diprifusor® module to deliver propofol by target-controlled infusion in a laboratory experiment.

Methods: Three infusion devices (Graseby 3500®; Fresenius Vial Master TCI®; Alaris TIVA-TCI®) were studied when infusing propofol at six different target concentrations (1, 1.5, 2, 3, 5, 8 µg mL−1) over 10 min. This procedure was repeated five times to average each target. Precision measurements were based on the volume delivered and a mean performance error was calculated.

Results: The mean performance error bandwidth for all pumps was from −2.07 to 4.22% with a 95% confidence interval always <4.5%. There was a higher variability at lower target concentrations associated with lower infusion rates. The Alaris TIVA-TCI® pump showed the largest overall bias whereas the Fresenius Vial Master TCI® pump had the smallest divergence and the lowest variation across all target concentrations. The Graseby 3500® pump had the smallest range in mean performance error with an acceptable variation (95% CI <2%).

Conclusions: Despite the differences between the pumps, which may be related to the synchronization of the hardware components, the absolute inaccuracies in the physical performance were low and presumably negligible from a clinical point of view.

Factors affecting flow through blood administration sets in vitro were assessed under gravity-fed and pressurized conditions including an assessment of the influence of the intravenous (i.v.) cannula and Luer lock fitting. The fastest gravity-fed flow of 4.775 mL s−1 was obtained through the largest internal diameter (ID = 4.8mm) blood administration set. Flow through blood administration sets with ID = 3mm was 50% of this. Flow increased over base-line through all the administration sets when the i.v. cannula was removed (range 18–50%) and increased further over base-line when the Luer lock fitting was removed from the distal end (range 26–129%), indicating that these are rate-limiting steps in the system. The Y-type trauma set with the largest diameter tubing facilitated the fastest flow, although flow through all the Y-type trauma sets produced lower flow rates than the corresponding blood administration sets, which may reflect their relative increased length. The ideal blood administration set should have an internal diameter at least 4mm and be less than 170 cm in length.