During my training classes on biologic infusions, one of the frequently asked questions is…do you use one bag or two bags when you infuse a biologic agent?

2 bags: After an IV access is established, most nurses directly connect  a primed IV tubing (usually with Normal Saline) to the IV catheter. This is considered the primary IV line and infuses at a keep open rate. When the biologic agent is reconstituted and mixed,  the common practice is to spike the bag with biologic agent using  a separate tubing (attach a filter, if required) and let the solution run through the entire length of the tubing. The tubing with the biologic agent is then piggybacked into the lowest Y site of the primary line of Normal Saline. In this set-up, the nurse can begin the infusion of the biologic agent,  with the choice of either turning off the primary NS line or simultaneously running at a slow rate.

1 bag: After an IV access is established, the nurse attaches an end cap or needless cap to the IV catheter and flushes the IV catheter with saline flush to keep patent. When the biologic agent is reconstituted and mixed,  the nurse  spikes the bag with biologic agent using  a separate tubing (attach a filter, if required) and let the solution run through the entire length of the tubing. The tubing with the biologic agent is then connected to the end cap and the infusion begins.

There is a variation to the 1 bag method I described. That is, when the nurse uses one NS bag with tubing/filter primed with Saline, directly connects to the IV catheter and infuses at keep open rate.  The  nurse will then  either add the reconstituted biologic agent (usually in a syringe) into the existing NS bag or the existing NS bag is switched with the bag containing the biologic agent. The biggest concern with this method is that there’s mostly saline in the tubing before the patient begins to receive the actual biologic agent.

I strongly recommend 2 bags as the preferred method when infusing biologic agents for several reasons:

1. A closed system is maintained with little to no manipulation
2. Allows for simultaneous infusions of both the biologic agent and NS if needed.
3. In the event of an infusion reaction, the biologic agent can be turned off without having to disconnect at the IV site
4. The NS bag can be infused before, during and after providing additional fluids to the patient, if desired

If cost is an issue with the use of a second NS bag, nurses should consider the safety factor and  how quickly they can disconnect the biologic agent tubing from the IV site during an infusion reaction, infuse NS to clear the line and manage the reaction. While infusion reactions during biologic infusions are infrequent, it can potentially occur at anytime during the first or subsequent infusions.