You may know that you can use the Spectra Optia™ Apheresis System to perform a straight exchange protocol or depletion protocol. In some cases, though, a combination of the two is literally what the doctor ordered, in the form of a red blood cell exchange (RBCX) depletion/exchange procedure.

During a depletion/exchange, each protocol is performed in sequence during a single session. It may be particularly useful when there is a desire to reduce exposure to donor red blood cells (RBCs) for patients with chronic red blood cell exchange needs, such as those with sickle cell disease (SCD). Let’s take a closer look at why that’s the case, as well as some tips for using this procedure on Spectra Optia.

Why use depletion/exchange versus stand-alone RBCX?

Any RBCX exchange procedure is used to remove defective or excessive RBCs and replace, or exchange, them with donor cells. In a typical RBCX procedure, the patient’s RBCs are removed at the same time donor RBCs begin to infuse. That means the patient and donor RBCs mix — and some of those donor cells may be sent to the remove bag.    

On the other hand, a depletion/exchange procedure has two distinct steps. First comes depletion, where the patient’s RBCs are removed, decreasing the patient’s hematocrit (Hct) to a physician-prescribed level, while replacement fluid, such as saline or albumin, is given. Once depletion is complete, exchange starts as donor RBCs are infused, increasing the patient’s Hct to the ordered target endpoint.

(Spectra Optia automates both phases of this previously manual procedure, which is commonly known in apheresis literature as the isovolemic hemodilution procedure.)

The two distinct steps of a depletion/exchange procedure mean that more of the patient’s own RBCs are removed during depletion and no donor RBCs are sent to the remove bag. Because of this, a lower volume of donor cells may be required, thus reducing patient exposure.

Note that the ordering physician should consider whether the patient's condition will tolerate a decrease in Hct to achieve the desired outcome.

For more information on depletion/exchange ordering considerations, review these guidelines. 

How does depletion/exchange impact run targets?

Using the RBCX depletion/exchange procedure may decrease the amount of replacement RBCs needed to attain the desired fraction of cells remaining (FCR) target for some patients. Or, when there is a set volume of replacement RBCs being targeted, depletion/exchange may allow for a lower FCR. Both situations may occur with patients who have frequent exposure to donor RBCs due to chronic RBCX treatment — such as patients with sickle cell disease.

In the examples below, you can see how a stand-alone exchange compares to a depletion/exchange with the same patient parameters for total blood volume (TBV), Hct, and fluid balance.

How do you select an RBCX depletion/exchange procedure?

These steps explain how to select an RBCX depletion/exchange procedure on Spectra Optia if a physician has ordered one.

For more information

To learn more about the benefits of RBCX depletion/exchange and how to run this protocol on Spectra Optia, review this procedure training and the operator’s manual or contact your Terumo Blood and Cell Technologies representative.