Effect of central venous pressure on fluid delivery during start-up of syringe infusion pumps for microinfusion.

Abstract

Intravenous administration of highly concentrated and potent drugs at low flow rates is common practice, particularly in critically ill children. Drug delivery during infusion start-up can be considerably delayed by intrinsic factors of syringe infusion pump assemblies. The impact of central venous pressures on the course of start-up fluid delivery of such microinfusions remains unknown. Infusion volumes delivered after activation of the start button in a conventional 50 mL syringe infusion pump assembly equilibrated (representing classical in vitro testing) and not equilibrated (representing real clinical conditions) to central venous pressure levels of 0, 10 and 20 mmHg at a set infusion flow rate of 1 mL/h were measured using a fluidic flow sensor. The experimental setup mimicking real life conditions demonstrated considerable differences in fluid delivery during pump start-up depending on central venous pressure. A central venous pressure of 0 mmHg resulted in massive fluid delivery at infusion start-up, while central venous pressure levels of 10 and 20 mmHg resulted in retrograde flows with related mean (95% CI) zero-drug delivery times of 3.22 (2.98-3.46) min and 4.51 (4.33-4.69) min, respectively (p < .0001). Depending on central venous pressure level, connection and starting a new syringe pump can result in significant antegrade or retrograde fluid volumes. In clinical practice, this can lead to hemodynamic instability and hence requires clinical alertness. Further research and methods to improve start-up performance in syringe infusion pump systems are desirable.