Note: Descriptions are shown in the official language in which they were submitted.
Field of Inve~tion
The present in~ention relate~ to a pump intended ~or automatic
and ~low drainage of a vial containing a ~olution, preferably a
medical solution. ~he drainage i~ performecl ~uring time pexiod
adapted and predetermined for the intended u~e.
~ackaround of the invention
Parenteral medicament~ mi~ht be administered intramuscularly or
lntravenou~ly to the patient. The lntravenou~ treatment might bs
performed through a contlnous lnfu~ion, lntermittent infu~ion or
lS a ~o call~d bolu~-in;ection.
The continou~ in~ection give~ the diqadvantage that the ves3el~
are expo~ed for a very long time to -the admini3tered drug, which
increa3es the ri~k of thrombophlebi-tl3. Fur-ther, 3ub~tances ~uch
a3 penicillines are unsuitable for continou~ lnfusion becau3e
they are not table in ~olution and therefor might become inac-
tive during the lnfu310n.
The intermitten-t infu~ion i3 continued for a ~horter time
period, e.g. 30 to 60 minutes. A bolu~-injection is an inJection
which i~ continued for about 3 to 5 minute~ and ~here the ~olu-
tion in~ected has a higher concentratlon of the drug than 1~ the
case with the lntermittent infu~ion ~olution. Both the~ meth~ds
of adminl~tratlon results in that pharmacokinetically high peak-
concentrations are obtained in blood after a ~hort time. ~letime period durlng which the ves~el~ are exFo~ed to th~ admini~
tered ~ tance i~ ~h~rt, which means that the frequency of
thrombophlebitis i8 reduced.
The active drug, whlch 1~ kept in a glas bottle, i~ in the case
of the bolus in;ection di~solved in s-terile water by 3uction of
the water in a first ~tep from a gla~ bottle with the aid of a
syringe and a 3uction cannula. The water 13 ~prayed in-to the
2~
gla3 bottle contalnlng the active drug and a solu-tion water-druy
i9 obtained. In this procedure a positive pressure is oft~n
obtained in the glass bottle resulting in leakage of the actlve
drug. Thi3 craates a great ri~k for the personnel from a sensi-
bilisation point of view. After the mixing ~tep, the ~olution i~sucked back into the ~yringe from the the gla~s bottle and after
the exchange of the cannula tha drug mlght be in~ected in a ~ein
during 3 to 5 minute3. T~is procedure glve~ th~ disadvantage
that the nurse is bound to the slckbed durln~ the ln~ection pro-
cedure.
For the performance of intermittent infu3ion for e.g. about 30
minutes an adapter i~ u~ed ln the currently used adminlstraticn
. , . ,. _.
procedures for the transfer of a sterile powder to an in~u~lon
pla3tic bag with for sxample 100 ml phy~. ~odium chloride,
where~pon an infu3ion aggre~ate i~ coupled to the p tie~t ~or
the administration of the dis301ved drug. This way of administ-
ration lead~ to high co~t~ for the non-returnabl~ material used
in the administration, which co~t~ of-ten greatly exceed the c03t
of the drug itself.
The ~afety demand~ and a hard strive to reduce cost~ in the
medic~l ~ervice has resulted in that one currently looks for
les3 expensive drug~ while at the same time the need for both
effective and ~ecure methods of administratlon, which at -the
same time offer a reduction in costs, increases.
Various device~ for automatic and continous admini3tration of
drug solutions to a pati~nt are previously known.
In US A-2 605 765 an automatlc syring~ i~ disclo~ed, which con-
taln3 both a medical solution and a driving device for the con-
tinuous in~ection la~ting for 48 to 72 hour~. The device i~
~mall and iq adapted to be carried by the patient during the
whole ln~ection proce~s without much inconvenlence. A driving
spring bia~es a piston in the direction of a partition wall with
a throttle valve between two chambers, whereby a viscous liq~ld
~lowly flow~ Erom the one chamber into the ~econd. The ~econd
2~0 5 ~
chamber 1~ restrlcted by a movable piston, which by th~ vlscou3
liquid i~ Eorced againRt the medical 301ution, which thereby i8
ln~ected ~lowly into the patient.
In US-A-3 474 787 i~ di3clo3ed a manually managed syringe aimed
at a timely ~horter ln;ection and wher~in the content of an in-
~ection vlal i8 emptied with a ~peed that i3 manually ad~ust-
able. The drainage i~ per f ormed hy the action of a pressurs
spring which bia~a~ a piston in the direction of the vlal ~uch
that a pumping liquid by the pi~ton i~ forced through ~ conduit
including a valve arrangement from the front chamber ln front of
the pi~ton to the back cha~er behind the ~ame. The movement of
the_piston i8 tran~ferred to the output pi~ton of the v:L~l ~o
that output and in~ection of the ~olution take place.
In US-A-4 437 859 i9 di~clo~ed a driving unit o~ ~ syr~l~ge,
which dri~ing uni~ compri~e~ two displaceable plqton~ each in
one cylindrical chamber. The chamber~ communicate wi-th each
other though a piping, which contain~ a pressure resulator, a
flow regulator and a needle valve. One of the pis-tons i~ connec-
ted to a driving arm for the output pi~ton of the ~yringe. When
the dri.ving unit ls loaded a syringe might be placed in ths dri-
ving unit. A spring biases one of the pi~ton~ again~t a driving
liquid, which adjustably 910wly flows through the connec-tion
between the chambers and drive3 the other pi~ton on in front. A
~pecial ~ecurity device i~ arranged in order to guarant0e tAat
the driving arm of the output plston of the ~yringe ~tops in
ca~e of a leakage or the like.
The prlor art davices disclo~ed above for the automatic and 310w
feeding o~ ~ m~dlcal 301ution to a patlent all ~uf~er from a
numbor o~ drawbacks.
- In all ca~es the output i~ performed by ~pring bla~, which
mean~ that if leakage or o-ther breakage ~hould occur in the
apparatu~ a non-~upervi~ed output and drainage of the con-
tent~ of the ~yringe lnto the patient wlll occur. Thi3
could lead to a cata3trophy for the patient. In order to
2~
avoid thi3 risk of accident~ the apparatus must be comple-
mented with certain complicated and expensive security de-
vice~.
- Feeding with ~pring~ leads to the drawback t~hat the power
o~ feeding i~ not linear, which gives a ~o~-unlform pres-
~ure on th~ pi~ton.
- The con~tructlons ars complicated and ~o ~xpen3ive to manu-
facture that they do not form a reali~tic alternative for
the currently used and above disclo~ed disposable equip-
ment.
,. . . .
- Time consumlng ad~ustements by the ho~pital perso~lel is
necessary for the prior art d~vices for the ad~u~tr~ent and
re~llation of the flow in order to obtaln the desired ln-
~ection or infu~ion time.
~a~ic concept of the-LnyQn~inn~
The ob~ec~ of the pre~ent invention i~ to ~olve the above p~ob-
lems by an infu~ion pump, which provides a ~afe, control~ed,
automatic and ~low dralnage of a liquid-containing vial. More-
over, the infu~ion pump, thank~ to it~ ~imple constructive de-
sign, offer~ an admin1stration method preferably for intermlt-
tent infusion, which offer~ reduced costs for the medical ser-
vlce.
The~e ob~ect3 are attained through an infusion pump of the kind
discussed in the preamble of thi~ application, which i3 charac-
terised ln that the pump comprise~ a closed ~ump housin~ wlthin
which a pumping liquid 1~ arran~d to ~low through a throttle
valve provided between a first and a ~econd chamber in the p~p
hou3ing. The first chamber i~ on the one ~ide restricted by one
~ide of pump piston, whicn is reciprocahle withi.n a pi~ton cy-
linder, and which pump pi~ton for the discharge of the solution
is arranged to be driven by a vacuum on the other ~ide of the
pump piston.
æ~
Further advantageous characteri~ing features of the invention
appsars from the following ~pecification of embodiments and from
the 3ubclaim~.
The pump pi~ton of the lnfusion pump is thu~ driven by a vacuum
formed behind the piston when the pump is loaded. Tha pump ho~-
~ing is thus on the oppoosite side of the pi~ton di~ided into
two chambars, both of which are filled wlth p~mping liquld,
which might flow through a control valve in both directions bet-
ween the chambers. The wall of one of the chambers is restricted
by a flexible membrane, which creates a variability of the inner
voluma of the chamber and thus a variability of the amount of
pumping llquid contained in the chamb~r. Upon loadlng the inner
15 Yolume of said chamber increases while the chamber vol~ne gradu-
ally decreases during the dralnage phase.
The pump according to the invention has th~ advantage, in oppo-
~ite to previous con~truction~, of being completely safe if a
leakage or breakage ~hould occur in the construction. In such a
ca~e the vacuum bullt up behlnd the pi~ton d~ring the loadlng
will be balanced. This will result in that the pump stop~ and
the infusion is interrupted. The ~ame situation will occur, i.
e. the pump stops automatically, when the syringe or the vial i~
empty and the complete dosage of medicament i~ in~ected.
The pump can cooperate with an ordlnary syringe, which i9 well
known by m~dical staff ~oth from a functional as well as from a
handling point of Vi8W, but also other type~ of vlal3 are pos-
sible for cooperation with the pump. With the ~yringa or withany other suitable vial mounted ln ~he loaded infuslon pump, an
infusion tube with cannula 18 attach~d from the syringe to the
patient, whereby the in~u~lon i.~ ~tarted. When u3ing a ~yringe
or vial with ~cale mark3 the per~onnel at any time miyht read
how much of the medicament 1~ glven.
With "vlal" ls ment different type~ of clossd containers, con-
taining a 301ution, with or without a piston reclprocable in the
contalner for output the 301ution.
The time con3umed for dralnage of the ~yringe or the vial i~ de-
termined by the form of the flow valve and the ~ize of the valve
body. Different valve body size~ corre~ond to difierent lniu~ion
times, which mean~ that no work is demanded from the medlcal
staff for ad~usting of tha output flow, unllka the sy~tem~ cur-
rently u~ed, which demand a considerable ei'.fort from the person-
nel in order to obtain an intended lnfustion ra~e. A system
which accor~in~ to the invention does not have to be adjusted
leads a safe 3ystem, slnce no ad~ustemant error3 can oc~ur be-
cau3e of the human factor. The drainage might sultably ~e per-
formed during ~ time period of 30 och 60 minute~ but al~o infu-
sion periods of a~o~ 24 hour~ are of intetre~t, e.g. in aneste-
sia .
The pump might ~e used without an external 30urce of energy,
which i3 an advantage wl~en moving patients or if the patient
stays at home. The pump i3 easy to handl~ and to load and the
infu~ion can easily be 3topped by removing the syringe from the
pump .
The infu~ion pump according to the present invention is suitable
for autoclave treatment or 3terlli~ation with damp, ~hich i~ a
great advantage r~garding to infectiou~ d~ea~e~, e.g. in an in-
fectious clinic.
~
One embodi~ent of tho invention and modification~ therev~ are
de~cribed ln detall below wlth reference to the attached dra-
wings, wherein
Fig. 1 shows a 3ide view of the infusion pump in unloaded po-
sition wi-thou-t any mounted vial or syringe;
~3~
Fig. 2 ~how~ a sectional view of the infu~ion pump according
to Fig. 1 with the pump in loaded position and with a
mounted 3yringe therein;
Fig. 3 ~how~ the infu3ion pump according to Fig. 2 in a posi-
tion of current output;
Fig. 4 hows the infuslon pump accordi:ng to FIg. 1 from
above;
Fig. 5 shows the infusion pump according to Fig. 1 from ~e-
low; and
Fig. 6 ~hows a ~ectional view of an alternati~e embvdiment of
~h~ infu~ion pump.
~tail~d d~cri.~tion of ~referred e~bodiment~ of th~ ntlon
Fig~. 1 - 5 3how a fir~t embodiment of the infusion pump accor-
ding to the invention, which comprise~ a pump housing 2 in the
extension of which i3 provided a loading housing 4 with two dia-
metrically oppo~ed and longitudinal openlng~ 6. The outer end of
the loadlng hou~ing i~ externally provided wi-th a groove 8 for
the cooperation with an internal fold 10 on a removable and
exchangeable syrlnge adapter 12. The ~yringe adap-ter 12 i3 a
carrier for an ordinary ~yringe, T~hereby an internal gripping
groove 16 i~ of a size and has a dlameter corresponding to the
gripp 18 oi a specific syringe ~o that the ~yrlnge might be
fixed in the ~yri.nge adaptor, when lt ha~ been introduc~d
through the open part o~ the adapter and the grip of the 3yringe
ha~ been placed in the gripplng groovo 16. The cross ~ectlon of
the adapter l~ has an exten~ion which is le~ tha~ hal~ a clrcle
ln order to b0 ablo to lock the oval gripp 18 of the ~yri.nge in
the adapter. In order to insert the ~yringe 14 into or to loo~en
the same from the adapter 12 the oval grlp 18 thu~ has to be
turned a little to be able to pass through the opening in the
adapter, Yince the maximum width of the grip 18 iq larger than
the opening of the adapter.
2~
A number of 3yringe adapter~ 12, which are identical beside~ the
~ize of the grlpplng groove 16 exi~t a3 accessorle~ to the in-
fusion pump in order to be exchangeably mountable on the loading
housing 4. The infu3ion pump can be adapted to another ~ize of
syringe by a mere exchange of the adapter 12.
The pump hou~ing 2 compri~e3 a piston cyinder 20 in which a pump
pl~ton 22 with a surrounding piston ya~ket 24 i9 reciprocable.
The pump pi3ton 22 i~ on one side provlded with a pi~ton rod 26,
which pa~3es through an inlet 28 in the bottom of the pi~ton cy-
linder. A shaft ga3ket 30, preferably an O-ring of teflon, is
provided in the inlet 28 in order to 3ealingly abut the pi~ton
rod 26 at it~ mo~ement back and forth through the inlet 28. In
the end of the pi3ton 3haft 2S, which ln all possible position~
of the piston i~ located out~ide the pi~ton cylinder 20 in the
lo~ding hou~ing 4, i~ mounted a threaded adju~tment ~crew 32.
The adjustement 3crew 32 ~hall after adju3tement and fine 3et-
ting abut the thumbplate 34 of the 3yringe monuted in the infu-
qion pump. The adju~tement 3crew 32 i~ fluted around the peri-
phery and i~ eaqily accesible for ad~u~tement from both ways
through the longitudinal opening3 6. A 3trap 62 i~ 3tretched
from the ad~u3tement 3crew 32 around the pump housing 2 and back
to the ad~u~tement screw 32 and thereby form~ an aid for the
loading of the pump, which will be described in more detail be-
low.
The pump hou~ing 2 further comprise~, on the slde of th~e pump
pi~ton 22 oppo~ite the pi3ton rod 2fi, a flr~t 36 and a 3econd 3
chamber, which both are filled wlth a pumping liquid 40, prefer
ably silicon oll, and which chamber~ 3~, 38 are separaed by a
throttle valve 42. The internal volume of the first chamber 36
varies from a minimum to a maximum by the di~placement of the
pump pl3ton 22 in the pi~ton cylinder 20. The lnternal volume of
the 3econd chamber 38 varies in that one of the wall3 of the
chamber 38 is formed by a flexible membrane 44, 30 that a mini-
mum volume i3 obtained when the merr~rane wall is concave and a
6~5~
maxlmum volume i~ obtained when the membrane wall i~ forced out
to a convex position. In order to protect the membrane wall 44
and in order to create a planar surface, which can be placed
~teadily again~t a ~upport, the outer end of the pump hou~ing 2
i3 covered by a protective cover 46, in which an air opening 48
1~ provided for air flowing in and out upon changing of th~ form
of the membrane wall 44. A ~uspension clamp 50 i~ fa~tened bet-
ween the outer end of the pump housing 2 and the protective co-
ver 46, wherehy the clamp in one position :i~ retract~d againYt
the prot~ctive cover ln~ide the outer edge of the pump hou~ing
and in an extended position perpendlcular to the protective co-
ver i~ meant to be an aid for the ~uspension of the pump above
the patient.
, . . . _ .
The throttle valve 42 comprise~ a valve hou~ing 52 with a cy-
lindrical valve chute 54, the val~e chute being provid~l with a
fir~t opening 56 towards the first chamber 36 and a ~cond ope-
ning 58 toward~ the second chamber 38. A cylindrical valve body
60, one end of which being planar and the other end being co-
nical, is slideably arranged in the valve chute 5~ between twoextreme position~ (I and II). The diameter of the cylindrical
valve body 60 ls les~ than ths diameter of the valv~ chute 54,
which means that a narrow cylindrical gap S4 is formed around
the valve body when it i~ situated in position I. It is the ~i~e
of thi~ gap 64 that determlne~ the time con~umed for the drai-
nage of the content of the Yyringe 14. A stop mean~ (not shown)
i3 arranged in the valve chute 54 at the planar end of the valve
body in po~ition II. Because the valve body i3 3topped in thi~
po~ition (II) a ~pace i3 formed for pumping llq~lid ~0 behind the
planar end portion of the valve body.
~he infu~ion pump according to Fig~ 5 work~ in the ~ollowing
way:
The infu~ion pump is loaded by the u3er pulling the ~trap 62 at
the protective cover 46 so that piston rod 26 and pump pi~ton 22
is forced into the piston cylinder 20. The pump pi~ton 22
thereby forces pumping liquid 40 from the fir3t chamber 36
zr~
through the fir~t opening 56 in -the valve housing 52. The pum-
ping liquid urges the valve ~ody 60 from position I to position
II where it i3 3topped agaln~t the ~top means in the valve chute
54. The pumping liquid 40 now might flow furthe.r past the co-
nical end of the valve body 60 and out through the ~econd ope-
ning 58 to the other chamber 38, into which the flexible mem-
brane 44 i~ pu~hed. r~hen the pump pi~ton ha~ reacA~d lt~ end po-
3ition ln the pi~ton cylinder the pump i~ completely loaded and
the in~ection 3yringe 14 can bo mounted.
The syringe adapter 12 ~uitable for the ~yringe 14 i~ put on ~he
groove 8 of the loading hou~ing and the oval grip 18 of the 9y-
ringe is tilted a little and is lntroduced into the adapter ope-
~ ._
ning and i3 locked in the gripping groove 16. The ad~ustement
screw 32 i3 adju~ted ~o that it abut~ the thum~plate 34 of the
syringe, the syringe i~ connected through a tube and a c~nnula
to the patient and the complete equipment i~ ~u~pended in the
su~pension bracket 50.
The d~vice i3 now ready for admini~tration of the drug ~olution,
which is contained in the ~yringe, by an output operation driven
by the vacuum pre3sure formed behind the pump pi3ton during the
loading of the infu3ion pump. The pumping liquid 40 thereby
tend3 to flow f rom the ~econd chamber 38 via the 3econd opening
58 ~here the liquid pres3ure acts on the end por-tion of the
valve body 60 30 that the complete valve body 60 i~ di~placed to
position I. The pumping liquid 40 thereby flow 310wly through
the cylindrical gap 64 and out through the first ope~ing 56 to
the fir3t ch~mber 36. The pump pi~ton 22 i9 pre3~ed by pumping
liquid equally ~low outwards ln the pl3ton cylinder 20, whereby
thls movmont i~ tran~ferred via the plston rod 26 to the pi~ton
oE the ~yrings 14, which expels the drug solution. When the ~y-
ringe ha~ been emptied of it~ contents the infu~ion pump wlll
~top automatically. The device i9 freed from the patient where-
upon the ad~ustement screw i~ threaded inwardly for a short di~-
tance in order to facilitate the relea~e of the empty syringe.
The grip of the syringe is tilted ~lightly ln order to be able
~o~
to be pa~sed through the openlng of the adapter of the ~yringe,
whereupon the ~yringe 1~ taken out of the loading hou~ing.
In Fig. 6 an alternative embodiment of the infu~ion pump is il-
S lustrated, which only dlffer~ from the embodiment shown i Fig~.
1 - 5 by a rapid ad~ustment device 66, which is an alternative
to ths adjustement screw. The rapid ad~ustement device 66 com-
prises a control button 68, which is di~placeable in a ~leeve 70
in the pump hou3ing 2. The back end of the control button
protrude~ a short dl~tance beyond the sleeve 70 and its inner
end is provided with a magne~ic part 72. In the sleeve ~0 and
around the front par-t of the control button a pressure spring 74
i~ prov~ded against whlch bias th~ control button 68 might be
pushed 30 that the magnet 72 abut~ the wall of the va~ve hou~ing
52. In thi~ position the force of the magnet aff~cts the valve
body 60, which i9 made of metallic material ~o that it i~ main-
tained by the magnet 72 in po~it10n II lnstead of being di~pla-
ced by the pumping liquid to po~ition I in the valve chute 54.
As long as the control butten 58 is pres~ed the pumping liquid
40 pa~es fairly quick from the second chamber 38 and through
the valve housing 52 to the first chamber 36 30 that the end of
the piston rod 26 rapldly can move to the posi-tion for the
thumbplate 34 of the 3yrinye 14. In this position the control
button 68 i9 relea~ed and i9 biased out by the force of the
Ypring, whereby the magnetic force relea~es the grip of the
valve bod~ 60, which immediately i~ di~placed to po~ition I by
the liquid pre3~ure, whereby the ~low feading ~tart3.
The invention ls in no way restricted to the above described em-
bodlments, in~tead several modificatlon~ of the lnventionen i~
po~slble within the scope o~ the claim~. For example, scale
mark~ might be provided along ths loadlng hou31ng to ma}~e pos-
~ible a ~uccesive reading of the remaining or already in~ected
solution. The loading houslng might al~o be provided with one or
more lock mean~, which adiu~tably might provide a locking func-
tlon fc,r the movement~ of the thumb plate at the output. By 3uch
a locking function different aomunt3 of the content~ of the 3y-
1~2~
ringe be feed out automatically lnstead of the complete contentof the syringe. In~tead of ~e1ng cyllndrical the valYe body
might for example be spherical.
