Fluid-delivery rates of five small-volume infusion-pump syringes were compared. The study consisted of a comparison of the infusion-pump syringes in their respective infusion pumps (1) set for continuous delivery at 1 mL/hr, (2) set for continuous delivery at 3 mL/hr, and (3) set to deliver 1-mL bolus volumes during continuous delivery at 4 mL/hr. The Life-care prefilled 30-mL syringe (Abbott), the DBL 30-mL syringe no. 770205 (DBL Inc.), and the Pump-Jet 30-mL syringe no. 1931 (International Medication Systems) were tested in the Lifecare PCA Plus II infusion pump no. 4100 (Abbott). The 30-mL Pump-Jet syringe no. 1911 (International Medication Systems) and the DBL 30-mL syringe no. 709700 (DBL Inc.) were tested in the Stratofuse PCA infusion pump (Baxter). The infusion pumps were set to deliver fluid continuously at 1 mL/hr for 30 hours, and the solutions were collected separately and weighed. The procedure was repeated with the infusion rate set at 3 mL/hr for 10 hours. For the third part of the study, each syringe was tested to deliver 1-mL boluses with 0, 5, 15, and 25 mL removed from the syringe. The solutions were collected and weighed before and after each bolus was delivered. The volume of solution collected was calculated by using the specific gravity of the solution. The syringes delivered significantly different volumes during the first hour of infusion at both the 1- and 3-mL/hr rates. Differences also existed across time for most of the syringes. Bolus volumes varied greatly after infusion of 0 or 5 mL of fluid but were acceptable for the remainder of the infusions.(ABSTRACT TRUNCATED AT 250 WORDS)