Patent ID: 7309333
Filing Date: 2007-12-18
Classification: A61M

Abstract:
1. A method for delivering a fluid medication to a treatment site of a patient comprising: displacing a liquid fluid medication in an initial continuous stream from a fluid storage chamber to a pump flowpath by transitioning an elastic member from a more stressed position to a less stressed position, said pump flowpath including a flow restriction, a drip chamber, and an outlet tube, wherein said drip chamber has a drip chamber sidewall, an upper portion, and a lower portion, said flow restriction exiting into said drip chamber and said outlet tube positioned beneath said flow restriction in said lower portion separated from said flow restriction by a drip gap, wherein said outlet tube has an extension segment with an inlet opening and a smaller cross section than said drip chamber, said extension segment extending into said drip chamber through said lower portion toward said upper portion to define an annular fluid accumulation space between said outlet tube and said drip chamber sidewall in said lower portion, thereby segmenting said drip chamber into said fluid accumulation space and a remainder space; converting said initial continuous stream of said fluid medication to a drip stream in said flow restriction; accumulating at least some of said fluid medication exiting said flow restriction in said fluid accumulation space, while maintaining an air pocket in said remainder space to define an air-liquid interface between said fluid accumulation space and said remainder space; spilling said fluid medication in said fluid accumulation space in an essentially continuous steady-state manner over an edge of said inlet opening of said extension segment extending into said drip chamber and fixed at said air-liquid interface, thereby reverting said drip stream to a reverted continuous stream in said outlet tube; and conveying said reverted continuous stream of said fluid medication from said outlet tube to a downstream treatment site of a patient.