Blood Sampling Through Peripheral Venous Catheter in Infants

Venipuncture is performed on the opposite limb of the peripheral venous catheter. Within 3 minutes, a second sample is taken from existing peripheral venous catheter used for fluid administration. Intravenous fluids are then stopped for 30 seconds and a tourniquet applied proximal to the device for another 30 seconds. A 2-mL syringe is attached and 0.5 mL of blood aspirated and discarded. Thereafter, 2 mL blood is slowly drawn during about 15 seconds, into a different 2-mL syringe, to allow a gentle pumping action that may reduce vacuum in the syringe and thus hemolysis rates. Afterwards, the intravenous device is flushed with 2 mL normal saline and infusion restarted.