Many blood treatment systems employ filters to allow for diffusion or convective exchange of fluid and/or molecular species to and from blood. In dialysis, for example, diffusion exchange is provided in order to remove waste products from the blood of a person. Hemofiltration is similar but relies primarily on convection of fluids including waste materials combined with convective replacement of the removed fluid. Other treatments provide combinations of diffusion and convective transport and the varying relative contributions of convective and diffusive transport.
Dialyzers and hemofilters that are in common use are essentially the same and sometimes structurally identical. The most common construction is a disposable device with a microtubular filter fiber bundle that is terminated by inlet and outlet headers to provide inlet and outlet flow to and from the blood compartment of the filter. A casing surrounds the bundle and defines a non-blood (e.g., waste or medicament such as dialysate) compartment for a non-blood fluid to collect or flow. At least one port is in fluid communication with this non-blood chamber or channel (the term “non-blood compartment” may be used to identify broadly a compartment, chamber, or channel or any other circuit portion based on its being on the non-blood compartment of the membrane, the general term being “compartment”). Other types of hemofilters and dialyzers are referred to generally as filters, and there are configurations other than microtubular fiber bundle types that exist as well.
Extracorporeal blood treatment is commonly performed in a clinical setting with professional and highly trained caregivers and system operators. Some systems are operable by lower skilled personnel including at-home dialysis patients who may rely on a helper. In some known blood treatment systems, a blood circuit is formed by connecting a filter, a venous line and an arterial line in series. The circuit may be primed by circulating a priming fluid on the blood compartment to fill the blood compartment of the circuit. In flowing the fluid through the blood compartment, a closed loop may be formed. After the blood compartment is primed, the non-blood compartment may be filled with fluid by attaching a source of fluid, which may be dialysate and pumping the fluid through the non-blood compartment of the filter. Filters may trap air, especially because they tend to be constructed with a high surface area compactly arranged in a small volume. Operators routinely manipulate the filter to cajole air into flowing out of the filter. The manipulations may include tilting the filter and tapping on it as well as controlling the flow in a way that helps the air to accumulate and flow out of the filter.
The process of priming takes time and attention from workers. It also adds tedium and distraction to the task of delivering care. It poses risks if not consistently performed or if a worker has been improperly trained and can make treatment less efficient if not properly done. Thus, it is desirable to provide methods, devices, and systems that allow for priming that is convenient and effective.