Abstract: A method for reducing small volume subcutaneous leaks of therapeutic fluids during procedures to refill an implantable medical device includes reducing pressure in a reservoir of the device. A refill needle can be percutaneously inserted into a fill port in communication with the reservoir and therapeutic fluid can be delivered through the needle into the reservoir. Reduced reservoir pressure upon withdrawal of the refill needle from the port can result in reduced subcutaneous leakage of the therapeutic fluid.

Abstract: A method for reducing small volume subcutaneous leaks of therapeutic fluids during procedures to refill an implantable medical device includes reducing pressure in a reservoir of the device. A refill needle can be percutaneously inserted into a fill port in communication with the reservoir and therapeutic fluid can be delivered through the needle into the reservoir. Reduced reservoir pressure upon withdrawal of the refill needle from the port can result in reduced subcutaneous leakage of the therapeutic fluid.

Abstract: Devices, systems, and techniques for transitioning between different drug delivery sources or different drug concentrations may account for diffusion and mixing of drug within the fluid. In one example, a method may include determining a flow rate for a fluid to be delivered to a patient via a drug pump and a catheter in fluid communication with a reservoir of the drug pump. The fluid includes a drug. The method also includes determining a concentration profile of the drug delivered via the catheter, wherein the concentration profile identifies a volume of delivered fluid needed to achieve a target transition dose of the drug. The method further includes determining, by a processor and based on the flow rate and the concentration profile, an initial delivery period required to achieve the target transition dose by delivering the fluid at the flow rate.

Abstract: Devices, systems, and techniques for transitioning between different drug delivery sources or different drug concentrations may account for diffusion and mixing of drug within the fluid. In one example, a method may include determining a flow rate for a fluid to be delivered to a patient via a drug pump and a catheter in fluid communication with a reservoir of the drug pump. The fluid includes a drug. The method also includes determining a concentration profile of the drug delivered via the catheter, wherein the concentration profile identifies a volume of delivered fluid needed to achieve a target transition dose of the drug. The method further includes determining, by a processor and based on the flow rate and the concentration profile, an initial delivery period required to achieve the target transition dose by delivering the fluid at the flow rate.

Abstract: A needle and needle system that aids in determining needle position with respect to an implanted device. The system determines needle position by detecting changes in electrical characteristics and the system further may generate a cue to indicate proper needle placement within an implanted device. Methods for detecting needle position with respect to an implanted infusion device are also disclosed.