Multi-stage fluid delivery device and method

A fluid delivery device to deliver a substance to a patient at a stepped decreasing delivery rate comprising:

• at least first and second reservoirs;
• at least first and second springs having at least a mid-range of operation and being positioned adjacent to said first and second reservoirs respectively;
• at least one infusion device;
• a fluid communication path including said first and second reservoirs, and said at least one infusion device;
• and
• at least one flow restrictor in said fluid communication path.

A fluid delivery device to deliver a substance to a patient at a stepped decreasing delivery rate comprising:

• a reservoir;
• first and second springs having at least a mid-range of operation and being positioned adjacent to said reservoir;
• a fluid communication path between said reservoir and at least one infusion device;
• and
• a flow restrictor in said fluid communication path.

A fluid delivery device to deliver a substance to a patient at a stepped decreasing delivery rate comprising:

• first and second reservoirs having at least one common reservoir wall, wherein said first reservoir is disposed on a first surface of said common reservoir wall and said second reservoir disposed on a second surface of said common reservoir wall;
• at least first and second springs having at least a mid-range of operation and being positioned adjacent to said first and second reservoirs respectively;
• a fluid communication path including said reservoirs and at least one infusion device;
• and
• a flow restrictor in said fluid communication path.

A fluid delivery device for delivering a substance to a patient at an increment variable flow rate, comprising:

• an upper housing portion, having a body extending along a longitudinal axis between a distal and proximal end, and comprising a first chamber therein, said body having a first opening at said distal end accessing said first chamber;
• a lower housing portion slidably positioned within said first opening of said upper housing portion, said lower housing portion having a body extending along a longitudinal axis between a distal and proximal end, and comprising a second chamber therein, said body having a second opening at said proximal end accessing said second chamber;
• a plurality of springs, wherein each spring of said plurality includes a high, low, and mid-range of operation, and wherein said plurality of springs are positioned within at least one of said first and second chambers;
• at least one infusion device;
• and
• at least one reservoir in fluid communication with said at least one infusion device, said reservoir being positioned adjacent to at least one of said plurality of springs.

A method for infusing a fluid at a stepped decreasing delivery rate comprising:

• applying at least one substantially constant first pressure to a fluid contained in a reservoir system to provide a fluid flow;
• applying at least one substantially constant second pressure to a fluid contained in said reservoir system to continue said fluid flow at a reduced rate, wherein said second pressure is less than or equal to said first pressure and is applied as a stepped decrease in applied pressure from said first pressure;
• and
• directing said fluid flow to an infusion device.