Pumping infusions with a syringe may cause contamination of the fluid in the syringe

Clinicians often perform pumping of infusions with a syringe (PIS) to quickly deliver fluid or blood transfusion to patients, especially during an emergency. Despite the efforts of the clinicians, critically ill patients are prone to acquire catheter-related bloodstream infections. Although clinicians have reported the possibility of PIS contamination, no group of researchers has studied nor confirmed this possibility. Here, we examined whether PIS can cause bacterial contamination of the fluid inside the syringes, using microbiological tests, including the analysis Escherichia coli DH-5 alpha growth by measuring the absorbance at OD₆₀₀. We confirmed that contamination of fluid in the barrel was almost proportional to the applied volume of bacterial fluid. Aliquots of DH-5 alpha artificially applied on the surface of the gloved hand of an examiner, the plunger or the inner side of the barrel of a syringe could permeate inside the syringe. Furthermore, disinfection with ethanol before PIS almost successfully prevented bacterial multiplication. Our findings suggest that PIS can cause intraluminal contamination when performed with unsterilized hands, and that previous disinfection with ethanol can effectively prevent PIS-induced contamination. These results highlight the risk of PIS-induced contamination and the importance of disinfection in the daily clinical practice.