Infusion pumps delivering small quantities of fluids and doses of medications are tailored to the patients in a wide range of care settings. From 1 liter or more in an hour to 1-2 drops per hour, the flow rates can range from 0.1 to 999 ml/hr - creating a full 10,000-fold difference from the lowest to the highest settings [1]. Looking at the dosage diluted in normal saline, the difference is even larger that every drop matters to achieve the target medication outcomes.
The problem of flow accuracy and continuity is especially prominent for infusion therapy at low rates, like dopamine hydrochloride to light-weight neonates and norepinephrine in the ICU and ED that can be as low as single-digit micrograms/minute. With the small dose diluted in 50 mL of normal saline, every slight change in flow can lead to serious clinical consequences.
Even with correct infusion programming, the highly sensitive flow accuracy can still be affected by multiple factors including:
Reference
[1] Eskew JA, Jacobi J, Buss WF, Warhurst HM, DeBord CL. Using innovative technologies to set new safety standards for the infusion of intravenous medication. Hosp Pharm 2002;37:1179-1189
[2] Lee E K, Hong K Y, Kim Y, et al. Effects of infusion tubing line lengths and syringe sizes on infusion system compliance: An experimental study using a syringe-type infusion pump at low flow rate[J]. 2022.