Infusion apparatus and method

Implantable infusion apparatus comprising:

• A. a housing;
• B. a first collapsible infusate reservoir having an outlet and positioned inside the housing;
• C. means for collapsing said first reservoir to expel infusate from its said outlet;
• D. a second collapsible infusate reservoir having an outlet and positioned in the housing;
• E. means for collapsing said second reservoir to expel infusate from its said outlet;
• F. mixing means;
• G. a first flow path having a first flow restriction characteristic connected between said first reservoir and said mixing means;
• H. a second flow path having a second flow restriction characteristic connected between said second reservoir and the mixing means, said second flow path restriction characteristic being less restrictive than said first flow path restriction characteristic;
• I. a normally closed valve connected in said second flow path so that infusate flows from said second reservoir to the mixing means only when said valve is opened, the infusates from said first and second reservoirs, when said valve is opened, supplementing one another to produce an integrated dosage, and
• J. a fluid outlet from said mixing means for conducting said integrated dosage to an infusion site.

Implantable infusion apparatus comprising:

• A. a housing;
• B. a first collapsible infusate reservoir having an outlet and positioned inside the housing;
• C. means for collapsing said first reservoir to expel infusate from its said outlet;
• D. a second collapsible infusate reservoir having an outlet and positioned in the housing;
• E. means for collapsing said second reservoir to expel infusate from its said outlet;
• F. mixing means;
• G. a first flow path having a first flow restriction characteristic connected between said first reservoir and said mixing means;
• H. a second flow path having a second flow restriction characteristic connected between said second reservoir and the mixing means;
• I. a normally closed valve connected in said second flow path so that infusate flows from said second reservoir to the mixing means only when said valve is opened, the infusates from said first and second reservoirs, when said valve is opened, supplementing one another to produce an integrated dosage,
• J. a fluid outlet from said mixing means for conducting said integrated dosage to an infusion site;
• K. a fluid accumulator positioned in the housing and connected in said second fluid flow path upstream from said valve;
• L. flow restricting means connected in the second flow, path between the second reservoir and said accumulator, said restricting means having a restriction characteristic which is considerably more restrictive than said first and second flow path restriction characteristics, and
• M. said accumulator expelling its contents to said mixing means when said valve is opened so that the integrated dosage is dependent upon the various concentrations and volumetric flow rates.

Implantable infusion apparatus comprising:

• A. a housing:
• B. a first collapsible infusate reservoir having an outlet and positioned inside the housing;
• C. means for collapsing said first reservoir to expel infusate from its said outlet;
• D. a second collapsible infusate reservoir having an outlet and positioned in the housing;
• E. means for collapsing said second reservoir to expel infusate from its said outlet;
• F. mixing means;
• G. a first flow path having a first flow restriction characteristic connected between said first reservoir and said mixing means;
• H. a second flow path having a second flow restriction characteristic connected between said second reservoir and the mixing means;
• I. a normally closed valve connected in said second flow path so that infusate flows from said second reservoir to the mixing means only when said valve is opened, the infusates from said first and second reservoirs, when said valve is opened, supplementing one another to produce an integrated dosage, said valve being mounted in said housing and being accessible from without said housing so that it can be operated manually transcutaneously when the apparatus is implanted subcutaneously and
• J. a fluid outlet from said mixing means for conducting said integrated dosage to an infusion site.

Implantable infusion apparatus comprising:

• A. a housing;
• B. a first collapsible infusate reservoir having an outlet and positioned inside the housing;
• C. means for collapsing said first reservoir to expel infusate from its said outlet;
• D. a second collapsible infusate reservoir having an outlet and positioned in the housing;
• E. means for collapsing said second reservoir to expel infusate from its said outlet;
• F. mixing means;
• said mixing means comprising a mixing chamber having a selected volume so that an integrated dosage containing a progressively lower percentage of bolus infusate continues to flow to the infusion site for an appreciable time after said valve is closed;
• G. a first flow path having a first flow restriction characteristic connected between said first reservoir and said mixing means;
• H. a second flow path having a second flow restriction characteristic connected between said second reservoir and the mixing means;
• I. a normally closed valve connected in said second flow path so that infusate flows from said second reservoir to the mixing means only when said valve is opened, the infusates from said first and second reservoirs, when said valve is opened, supplementing one another to produce an integrated dosage, and
• J. a fluid outlet from said mixing means for conducting said integrated dosage to an infusion site.

Implantable infusion apparatus comprising:

• A. a housing;
• B. a first collapsible infusate reservoir having an outlet and positioned inside the housing;
• C. means for collapsing said first reservoir to expel infusate from its said outlet;
• D. a second collapsible infusate reservoir having an outlet and positioned in the housing;
• E. means for collapsing said second reservoir to expel infusate from its said outlet;
• F. mixing means;
• G. a first flow path having a first flow restriction characteristic connected between said first reservoir and said mixing means;
• H. a second flow path having a second flow restriction characteristic connected between said second reservoir and the mixing means;
• I. a normally closed valve connected in said second flow path so that infusate flows from said second reservoir to the mixing means only when said valve is opened, the infusates from said first and second reservoirs, when said valve is opened, supplementing one another to produce an integrated dosage,
• J. a fluid outlet from said mixing means for conducting said integrated dosage to an infusion site, and
• K. first and second valved passages leading from the outside of said housing leading respectively to said first and second reservoirs by which said reservoirs may be refilled with infusate.

The method of dispensing infusate inside a living body comprising the steps of

• A. conducting infusate in a first concentration or type at a first selected flow rate along a first path to a mixing chamber;
• B. conducting infusate in a second concentration or type at a second selected flow rate along a second path to said mixing chamber;
• C. conducting the infusate from the mixing chamber along a third path to an infusion site in the body;
• D. normally blocking the infusate flow from the second path to the chamber;
• E. momentarily unblocking the flow from the second path to the chamber at determined time intervals so that in said chamber infusate in the second concentration or type supplements infusate in the first concentration or type providing an integrated dose to the infusion site, and
• F. the chamber volume and third path flow rate being related so that when the flow from the second path to the chamber is blocked, the percentage of the second concentration or type infusate in the integrated dose conducted to the infusion site falls off generally expotentially with a selected time constant.