Cannula assemblies and ambulatory infusion systems with pressure sensors made of stacked coplanar layers

摘要

Cannula assemblies with pressure sensors made of stacked coplanar layers and ambulatory infusion systems comprising the same are disclosed. The cannula assemblies include a hub and an infusion cannula. The hub includes a pressure sensor and a fluid channel fluidly coupled to the infusion cannula. The pressure sensor is formed from a stack of coplanar layers including a top layer, a base layer an electrode layer and a counter electrode layer. The fluid channel is positioned between the top layer and the base layer. The electrode layer is positioned between the top layer and the base layer and coupled to the fluid channel. The counter-electrode layer is positioned between the top layer and the electrode layer. A spacer layer having a through cut-out defining an electrode cavity is disposed between the top layer and the base layer such that the electrode layer extends across the electrode cavity.

主权项

1. An ambulatory infusion system for the infusion of a liquid drug into a patient's body over an extended time period, the ambulatory infusion system comprising:
an infusion device an infusion cannula fluidically coupled to the infusion device; a measuring unit; a pressure sensor electrically coupled to the measuring unit and fluidically coupled to the infusion cannula with a fluid channel, the pressure sensor comprising a stack of coplanar layers comprising: a rigid top layer and a rigid base layer, wherein at least a portion of the fluid channel is positioned between the top layer and the base layer; an electrode layer positioned between the top layer and the base layer and flexibly coupled to the fluid channel; a counter-electrode layer positioned between the top layer and the electrode layer, the counter-electrode layer and the electrode layer forming electrodes of a sensing capacitor; and a spacer layer defining an electrode cavity disposed between the top layer and the base layer such that the electrode layer extends across the electrode cavity, wherein positive fluidic pressure in the fluid channel flexes the electrode layer into the electrode cavity thereby modifying a capacitance of the sensing capacitor; and wherein the electrode layer and the spacer layer that are arranged between the top layer and the bottom layer are of substantially the same size.