Changing the syringe pump: A challenging procedure in critically ill patients

In the literature, the change of a syringe pump is described as a dangerous situation, especially in the case of vasoactive drug administration.

Different variables have been studied (central venous pressure, pump displacement in relation to the patient position, utilization of a stopcock, or a neutral displacement needle-free connector between the syringe and the infusion tubing) to understand their influence on medication administration in terms of backflow or bolus creation when changing the syringe.

We performed 576 measurements with different combinations. With respect to all the observations, in comparison with "time zero," we found the following differences expressed in microliters: 0 (±1) at the plunger opening; 0 (±3) at the syringe extraction from the pump; 0 (±7) at the syringe disconnection from the infusion tubing; 0 (±11) at the syringe reconnection to the infusion tubing; 1 (±7) at the syringe insertion in the pump; 3 (±23) at the plunger closing; 8 (±33) at the stabilization at the maneuver end.

The syringe change can be a very critical moment given different influencing variables. Syringe pump position, displaced higher than the patient level, always generates a medication bolus that is higher at the lowering of the central venous pressure value. The presence of a neutral displacement needle-free connector reduces the incidence of boluses. When the pump is placed at the patient level, the presence of neutral displacement needle-free connector reduces the establishment of boluses, even in a central venous pressure of -5 mmHg simulations.