Effect of infusion line connection and infusion line characteristics on start-up fluid delivery from syringe infusion pumps used for microinfusion.

BACKGROUND

Connecting an infusion line to a closed stopcock results in pressurization of fluid within the syringe infusion pump assembly leading to flow irregularities when opening the stopcock and activating the pump.

AIMS

It was the purpose of this study to assess the extent of pressurization under different conditions and its impact on start-up fluid delivery.

METHODS

Intraluminal pressures and start-up fluid delivery at 1 mL/h flow rate were assessed with connection of the infusion line 1 min (delayed connection) or immediately after purging (immediate connection) using two different infusion lines made from polyvinylchloride (PVC) or polyethylene (PE).

RESULTS

Delayed connection resulted in an increase of intraluminal pressures from zero to 5.1 [4.5 to 5.7] mmHg with the PVC line and from zero to 47.1 [44.8 to 49.3] mmHg with the PE line (mean difference 42.0 [95% CI 39.3-44.7] mmHg; p < .0001). Immediate connection resulted in an increase of intraluminal pressures from zero to 44.3 [41.8-46.8] mmHg with the PVC line and from zero to 61.3 [57.2-65.4] mmHg with the PE line (mean difference 17.0 [95% CI 11.8-22.2] mmHg; p < .0001). The increase in intraluminal pressures was significantly higher with PE lines for both delayed and immediate connection when compared to the PVC lines (mean difference 29.5 [95% CI 19.3-39.7] mmHg; p < .0001). Related fluid volumes delivered at 10 s and 360 s after starting the pump ranged from -252% to 1321% (10 s) of expected infusion volumes and from 59% to 129% (360 s), respectively.

CONCLUSIONS

Both, timing of infusion line connection after purging and infusion line characteristics considerably affect intraluminal pressures and start-up fluid delivery when connecting a new syringe infusion pump assembly to a closed stopcock. Consecutive alterations in drug administration can have considerable hemodynamic consequences when dealing with catecholamine infusions in critically ill patients.