The syringe infusion pump has been established as the instrument of choice for high-risk infusions, where potent drugs are often delivered at low rates of flow. However, numerous instances of unexpected flow error with consequent patient physiological impact have been reported. These include unwanted bolus delivery on release of line occlusion, dosage fluctuation due to pump height change and fluid reflux within the multiple pump installations now common in the Intensive Care Unit (ICU). This article examines the performance of a typical ICU syringe infusion pump and identifies mechanical compliance, inherent in commercial designs, as a source of flow error that should not be ignored by equipment designers. A prototype low compliance system is described and tested with performance compared to the conventional design, demonstrating advantages in terms of lower flow error.