Fluent material handling – with receiver or receiver coacting mea – Processes – Filling dispensers
Reexamination Certificate
1999-12-22
2002-03-26
Huson, Gregory L. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Processes
Filling dispensers
C141S021000, C141S027000
Reexamination Certificate
active
06360784
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to medicament pumps implantable in a body and more specifically to a device for filling high pressure reservoirs in medicament pumps implantable in a body.
2. Description of the Related Art
The implantable drug infusion pump (IDIP) has provided physicians with a powerful tool for administering a wide variety of drugs and other agents, such as pain killers, nerve growth factor, and anti-spasticity drugs, to very particularized sites within a patient's body, such as the intrathecal region of the spinal column. The IDIP has also freed some patients from the restrictions of typical intravenous drug infusion systems that typically include a wheeled cart that must be pulled around behind the patient.
An IDIP is ordinarily surgically implanted subcutaneously in the patient's abdomen. The IDIP has an internal reservoir for storing the drug or agent. After implantation, the drug or agent is delivered to a selected site in the patient's body via a catheter that is attached to the pump and tunneled subcutaneously to the selected site. Many medical applications calling for an IDIP require very minute do sages or drug or agent to be delivered to the selected site over a period of time. For example, dosages of 100 &mgr;l over a span of twenty-four hours are not uncommon.
Before the IDIP can be implanted in the patient's body, it must be filled with the applicable drug or agent. For many long-term applications, the IDIP may have to be refilled while the pump is still implanted within the patient's body. This is normally done by passing the drug or agent through a hypodermic needle that has been pierced through the patient's skin and coupled to the subcutaneously disposed IDIP.
A prior art system for refilling and IDIP is shown in FIG.
1
. The prior art system
10
includes a pharmacy syringe
12
, a filter
14
, a filling tube
16
, and an IDIP
18
. Filter
14
has an inlet
20
that is coupled to the discharge outlet
22
of the pharmacy syringe
12
. Filter
14
is preferably any of a number of well known types that prevent bacteria, sediments or other undesirable particles from passing through it and into the IDIP
18
.
The discharge orifice
24
of the filter
14
is coupled to the inlet end
26
of the filling tube
16
. The filling tube
16
terminates in a needle
28
. Pharmacy syringe
12
has a plunger
30
. As the plunger
30
of the pharmacy syringe
12
is depressed, drug flows from the pharmacy syringe
12
through the filter
14
and the filling tube
16
and into the IDIP
18
.
As shown in
FIG. 2
, the needle
28
enters the IDIP
18
through a septum
32
. Septum
32
provides a fluid barrier for a chamber
34
within IDIP
18
. Chamber
34
is fluidly connected to a reservoir
36
through a manifold
38
. Reservoir
36
is typically formed within a bellows structure
40
that is connected to manifold
38
. An outer shell
42
is attached to the manifold
38
around the bellows structure
40
. A sealed pressure chamber
44
is formed between outer shell
42
and bellows structure
40
.
A propellant gas is place in pressure chamber
44
. The propellant gas acts as a pressure-providing means to the bellows structure
40
that biases the bellows structure
40
to discharge the drug or other agent stored in the reservoir
36
. The propellant gas used to drive such a “gas driven” IDIP is a fluid that is in phase change between a liquid state and a gas state when, i.e., in equilibrium between phases at around 37 degrees (Celsius), which is the usual temperature of the human body. In programmable IDIPs such as the SynchroMed pump manufactured and sold by Medtronic, Inc. of Minneapolis, Minn., the propeulant gas is chosen to provide a pressure on the bellows structure of about 4 p.s.i. In this device, the metering of the drug or other agent out of the device is done through a peristaltic mechanism.
In constant rate IDIPs such as the IsoMed® pump manufactured and sold by Medtronic, Inc. of Minneapolis, Minn., the propellant gas is chosen to provide a pressure on the bellows structure of about 32 p.s.i. In this device, the metering of the drug or other agent is done through capillary tube that provides a relatively constant flow rate of drug or other agent out of the reservoir
36
. The reason for a higher pressure in the pressure chamber
44
in a constant rate pump with a capillary tube flow restrictor is that this higher pressure reduces the variability in flow rates of the drug or other agent due to atmospheric conditions such as barometric pressure.
As mentioned above, when refilling the IDIP, the drug or other agent is passed from a pharmacy syringe
12
through the filter
14
and the filling tube
16
and into the IDIP
18
where it passes into the reservoir
36
. However, the drug or other agent must enter the reservoir
36
at a pressure sufficient to overcome the pressure bias on the reservoir
36
from the propellant gas in the pressure chamber
44
. In the case of the IsoMed® pump, the drug or other agent must be delivered to the reservoir
36
at a pressure higher than 32 p.s.i.
Due to the principles of hydraulics, this 32 p.s.i. pressure is applied over the entire cross-sectional area of the plunger
30
. When refilling an IDIP
18
, typically the entire reservoir capacity of the IDIP is refilled. A typical IDIP
18
may have a reservoir volume of 20 ml, 40 ml or 60 ml. To refill an IDIP
18
with, for example, a 60 ml reservoir, a pharmacy typically prepares 60 ml of the drug or other agent and places it in a pharmacy syringe
12
corresponding in size to the amount of drug or other agent to be refilled, in this case, a 60 ml syringe. The 60 ml pharmacy syringe
12
could be coupled directly to the system
10
through the coupling of discharge outlet
22
and inlet
20
.
As is well known, the cross-sectional area of the plunger
30
of a relatively small syringe such as a 10 ml syringe is smaller than the cross-sectional area of a larger syringe such as a 60 ml syringe. As a result, the force needed to apply 32 p.s.i. to drug or other agent in a pharmacy syringe
12
is determined by multiplying 32 p.s.i. by the crosssectional area of the plunger
30
. In the case of a 60 ml syringe, this total force is on the order of 25 pounds. This is a larger force than many people are able to generate with their hands. On the other hand, because the cross-sectional area of a 10 ml syringe is about a quarter of the cross-sectional area of a 60 ml syringe, the total force needed to apply apply 32 p.s.i. to drug or other agent in a pharmacy syringe
12
is about 6 pounds. This force is well within the range of force that most people can generate with their hands.
As a result, many practioners, when refilling large reservoir pumps such as the 60 ml reservoir pumps, require the pharmacy to place the 60 ml of the drug or other agent to be refilled into several smaller syringes such as 10 or 20 ml syringes instead of in one large syringe. These smaller syringes allow the practioner to apply the drug or other agent to the reservoir
36
even in pumps such as the IsoMed® pump that have relatively high gas propellant pressures in the pressure chambers
44
. Unfortunately, using several smaller syringes instead of one large syringe means that each pharmacy syringe
12
must be attached and disconnected from the inlet
20
each time instead of once as would be the case for the larger syringe. With this increased number of connections and disconnections, there is an increased chance of infection entering the system or other problems occurring.
In view of the foregoing, it is desirable to provide a system that allows the practioner to easily provide the drug or other agent to the reservoir
36
of the IDIP
18
while at the same time minimizing the number of times the sterile connection between the pharmacy syringe
12
and the system
10
is broken. The present invention is directed to overcoming the aforementioned disadvantage. Throughout this disclosure, like elements, wherever referr
Borchard Craig F.
Guimont Jill
Hauch Tim
Johnson Patrick
Philippens Frans
Bauer Stephen W.
Berry Thomas G.
deVore Peter
Huson Gregory L.
Kinghorn Curtis D.
LandOfFree
Valved connector and method of use does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Valved connector and method of use, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Valved connector and method of use will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2855977