IV safety module

An IV safety module (2) is used with a peristaltic type IV pump (5) to prevent the unrestricted flow of IV fluid through an IV line (4) when the door (80) of the IV pump is open. A locking trigger (42) is pivotally mounted to the body. A spring (10) is mounted to the body and has a section (18) which compresses and collapses the IV tube closed, thus substantially halting and IV fluid flowing therethrough, as the spring biases the trigger to the tube clamped position. The safety module is mounted adjacent the pump and is configured so that closing the door of the pump depresses the trigger to open the IV tube.

BACKGROUND OF THE INVENTION 
Intravascular administration of fluids is ubiquitous in modern medical 
practice. These fluids encompass a wide variety, but they are generally 
water-based. Examples include saline solutions such as "normal saline" or 
sterile water mixed with sodium chloride to a final concentration of about 
0.9%. Other concentrations of saline solution, such as one-half or 
one-quarter the amount found in normal saline, are also widely used. 
Further examples of commonly employed intravascular fluids include 
Ringer's solution, lactated Ringer's solution, and water-based solutions 
which have other additives. These additives are too numerous to name, but 
include substances such as potassium chloride, potassium phosphate, 
glucose or dextrose, magnesium, phosphorus, calcium and many other 
compounds and elements. 
The indications for administering fluids are myriad and are well known in 
the art. A few of the many indications include dehydration, inability to 
take fluids by the oral route, and a need for medications which are most 
efficacious if administered intravascularly. Intravenous fluid 
administration is more widely practiced than intra-arterial 
administration, but both are examples of intravascular access to a 
patient. 
Intravenous drug therapy is well known in medical practice. Typically water 
soluble drugs are used. A few examples of some of the many intravenous 
medications in use include diuretics such as lasix, cardiac medications 
such as lidocaine, antibiotics such penicillin and aminoglycosides, 
hormones such as oxytocin and cortisone, analgesics such morphine sulfate, 
and chemotherapeutic agents such adriamycin and cis-platinum which are 
used in cancer therapy. In addition to these drugs and the previously 
mentioned fluids, intravenous therapy is also widely practiced for 
transfusions of blood and various blood components such as washed packed 
red cells and platelets. 
Methods of instituting intravenous therapy, such as intravenous fluid or 
drug therapy, are well known in the art and will only be briefly 
summarized here. A fluid source, usually a soft-sided plastic bag, 
contains a sterile fluid suitable for use in humans. The bag includes an 
access port to which a line or tubing is connected by means which 
frequently include a cannula. This tubing is in fluid communication with 
the patient's circulatory system through means which usually include a 
hollow needle cannula. The needle end is placed into the patient's blood 
vessel and the opposite end connects to the tubing. 
Although intravenous methods are most frequently used for intravascular 
therapy, intra-arterial therapy is also known and practiced. Because an 
arterial typically has higher native internal pressure than a vein, there 
are special problems involved in administering fluids or drugs 
intra-arterially. Use of an intra-arterial access device typically 
requires maintenance of higher pressure to deliver fluids as compared to 
an intravenous method. 
When administering intravascular fluids or other substances, it is 
frequently convenient to include a pumping mechanism along the line or 
tubing. This pump, which is often a peristaltic-type pump, assists in 
delivering a precise volume at a specified rate. If a pump is not used, 
some other flow monitoring means are used. For instance, the clinician or 
assistant may rely on gravity to create a pressure differential between 
the bag and the patient's vascular access to achieve flow. This usually 
consists of placing the bag or fluid source higher than the level of the 
entry point of the fluid into the patient. A rotatable knob at the exit 
portion of the bag is manipulated to control egress of the fluid. The pump 
method can be more accurate and reliable in delivering the desired flow. 
The pump generally involves a gear mechanism including rollers which accept 
the intravenous tubing. Pressure of the rotating rollers squeezes or milks 
the tubing to allow flow of fluid from the fluid source to the patient. 
Usually the tubing is curved over the gear mechanism which is covered by a 
door. The typical arrangement is that when the door is opened the tubing 
is not compressed at the point where the tubing enters the pump and thus 
free flow of the fluid is temporary permitted. Unfortunately it is 
frequently necessary to open the door to adjust the tubing or to solve 
some problem which has caused the machine to emit a warning beep or light. 
During this time, that is, when the door is open, there exists a risk of 
inappropriate fluid flow from the fluid source to the patient. Additional 
compromise can occur if the door is inadvertently left open or is not 
completely closed. This inadvertence can lead to inaccurate dosing of the 
fluid or medication contained in the fluid. Because the fluid flow is less 
restricted when the door is open than when the door is shut, inadvertence 
in leaving the pump door open would lead to overdosage of the patient with 
the fluid or medication. 
SUMMARY OF THE INVENTION 
The present invention is directed to an IV safety module for use with an IV 
assembly of the type including an IV bag or other fluid source, an IV line 
and, preferably, a peristaltic type IV pump along the IV line coupling the 
fluid source to the patient. The present invention provides a safety 
feature for pumps of the type described above, and use of the invention 
can enhance accurate dosing of a patient receiving intravenous fluids of 
medications. Additionally, the principles of the invention can be applied 
to pumps for use with intra-arterial fluid lines. 
The IV pump is of a type having a door which opens providing access to the 
section of the IV line which is engaged by rollers to pump the IV fluid 
along the IV line. The module includes a body mountable to the IV line 
adjacent the IV pump. A moveable locking trigger is mounted to the body 
for movement between tube clamped closed and tube open positions. A spring 
is secured to the body and biases the locking trigger toward the tube 
clamped closed position. In this position a section of the spring 
collapses a portion of the IV tube thus halting flow of IV fluid through 
the IV tube. 
One of the primary advantages of the invention is that it can be used with 
an existing IV pump, such as the Model 599B made by IVAC of San Diego, 
Calif., to insure additional safety by preventing unrestricted flow of the 
IV fluid to the patient. 
Another advantage of the invention is that the normally closed aspect of 
the safety module can be overridden to allow for operation without the IV 
pump. However, with the construction of the safety module, and the IV pump 
in place, the pump door cannot be closed until the safety module is no 
longer disabled, typically by sliding the locking trigger back to its 
normal, enabled position. 
The spring serves several functions. First, it acts as a clamping bar which 
pushes against and collapses the IV tubing. Second, it acts as an 
actuating arm which pushes upwardly on the trigger. Third, it acts as the 
source for the spring biasing force for these functions. 
Other features and advantages of the invention will appear from the 
following description which the preferred embodiment has been set forth in 
detail in conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1 and 2A-2C show an IV safety module 2 in conjunction with an IV line 
4 through which an IV fluid is directed from an IV source (not shown) to a 
patient (not shown). Safety module 2 is used in conjunction with an IV 
peristaltic pump 5, such as the Volumetric Pump made by IVAC of San Diego, 
Calif. as Model 599B. The portions of the peristaltic pump pertinent to 
the construction and use of safety module 2 will be discussed below in 
conjunction with FIGS. 3A and 3B. 
Module 2 includes a body 6 having a central bore 8 through which IV line 4 
passes. A clamp spring 10 is mounted to body 6 and includes a U-shaped 
spring portion 12 having a first tip 14 extending from an upper arm 16 of 
portion 12 and a tube clamp section 18 extending from a lower arm 20 of 
portion 12. Spring 10 also includes a second tip 22 connected to section 
18 by a connecting arm 24. Tip 14 passes into a hole 26 in body 6 while 
upper arm 16 is housed in a slot 28. A vertical portion 30 of U-shaped 
portion 12 is housed within a slot 31 formed in body 6. Lower arm 20 is 
positioned along a recessed surface 32. Spring 10 is held in position by 
use of a retaining plate 34 which includes a face portion 36, secured to 
the face 38 of body 6, and an overlying portion 40, which lies within a 
recessed portion 41 of body 6. Plate 36 includes three cylindrical pegs 
43, each about 0.12 inch (3 mm) long positioned to engage complementary 
holes 45 formed in face 38 of body 6. 
A locking trigger 42 is movably mounted to body 6 for pivotable movement 
between an enabled, tube clamped closed position of FIG. 2A and enabled, 
tube released position of FIG. 2B by the application of a force in the 
direction of arrow 63. This force can be applied by door 80 of IV pump 5 
as suggested in FIG. 2B. Trigger 42 includes a serrated upper surface 44 
to provide good frictional engagement for the user. The lower portion of 
trigger 42 includes a downwardly extending rib 46 which rides within a 
slot 48 formed along body 6. A pair of outwardly extending, rounded 
protrusions 50 extend laterally from the sides 52 of rib 46 and engage two 
semi-cylindrical cutouts 54 formed in slot 48. Thus, protrusions 50 within 
cutouts 54 allow trigger 42 to both slide axially within slot 48 and also 
pivot about protrusions 50. 
A slot 56 is formed through rib 46 and is sized to accept second tip 22 of 
clamp spring 10. As shown in FIGS. 2A and 2B, second tip 22 is held within 
one end of slot 56 by a first detent 58; however, when trigger 42 is in 
the enabled tube released position of FIG. 2B (and assuming rib 69 of door 
8, discussed below, has been removed from region 82 of slot 68), the user 
can move trigger 42 to the disabled, tube released position of FIG. 2C by 
moving, that is sliding, the trigger in the direction of arrow 60 of FIG. 
2C so that second tip 22 moves to the other end of slot 56. This prevents 
pivotable movement of trigger 42 from the enabled, tube released position 
of FIG. 2B in the direction of arrow 62 to the enabled, tube clamped 
closed position of FIG. 2A by engagement of the tip 64 of locking trigger 
42 beneath overlying portion 40 of retaining plate 34. 
Body 6 includes a first, generally vertical slot 66 formed part way through 
the body and sized to receive tube clamp section 18, connecting arm 24 and 
second tip 22. Body 6 also includes a second, generally vertical slot 68 
formed part way through body 6 positioned parallel to slot 66. Slot 68 is 
sized for receipt of a rib 69 on pump 5 as discussed below with reference 
to FIGS. 3A and 3B. 
IV line 4 passes through central bore 8 with the outer end 70 extending 
past the end 72 of tubular portion 74 of body 6. A hollow, tapered seal 
cone 76 is inserted into the interior of IV line 4 at end 70 and the IV 
line is drawn back into central bore 8 thus wedging line 4 within bore 8. 
Silicone pump tubing 78 is mounted over tubular portion 74 as shown in 
FIGS. 2A-2C. 
FIGS. 3A and 3B illustrate top views of pump 5 with safety module 2 mounted 
therein and door 80 in the open and closed positions. Although not clear 
from the simplified fragmentary view of FIGS. 3A and 3B, rib 69 of pump 5, 
used to keep IV line from pulling out of the pump, passes into slot 68 
when door 80 is closed. A portion of rib 69 also enters a region 82 
adjacent tip 64 of trigger 42. This is shown in FIG. 2B. Therefore, when 
safety module 2 is mounted within pump 5, trigger 42 is prevented from 
moving from the enabled, tube released position of FIG. 2B to the 
disabled, tube released position of FIG. 2C. If trigger 42 is in the 
disabled, tube released position of FIG. 2C, door 80 will not close all 
the way. See FIG. 2C. Pump 5 is constructed so that the pump will operate 
only when door is completely closed. 
In use, outer end 70 of tube 4 is inserted through central bore 8 past end 
72 of tubular portion 74. Seal cone 76 is inserted into outer end 70 and 
the outer end is pulled back into central bore 8 to wedge, and thus 
secure, outer end 70 within central bore 8. Pump tubing 78 is then slipped 
over tubular portion 74 and the assembly is mounted within pump 5 as shown 
in FIG. 3A. At this point, trigger 42 is in the enabled, tube clamped 
closed position of FIGS. 2A and 3A. Closing door 80 presses downwardly on 
trigger 42 thus opening IV line 4 by moving the trigger to the enabled, 
tube released position of FIGS. 2B and 3B. 
Safety module 2 can also be used without pump 5. Removing the assembly of 
FIG. 2A from the pump 5 causes the tubing to be clamped shut. To permit 
fluid flow through IV line 4, trigger 42 is depressed to the position of 
FIG. 2B; to maintain trigger 42 in the depressed condition, trigger 42 is 
slid in the direction of arrow 60 to the disabled, tube released position 
of FIG. 2C. 
Central bore 8 provides a generally cylindrical path over its entire 
length. However, a portion of central bore 8 above tubular clamp section 
18 of clamp spring 10 is depressed somewhat to provide a flat surface 84, 
corresponding to the straight line section of tubular clamp section 18, 
directly above the tubular clamp section. This can be seen in FIG. 2A by 
the inward deflection of the wall of IV line 4 as line 4 passes through 
body 6 adjacent tubular clamp section 18. Doing so helps ensure good 
sealing of IV line 4. To help prevent wear on line 4, a resilient tube 33, 
shown only in FIG. 1, can be mounted over section 18 of spring 10. 
Clamp spring 10 is shown sized to partially compress IV line 4 when trigger 
42 is in the tube released positions of FIGS. 2B and 2C. Clamp spring 10 
could be sized to leave IV line 4 undeflected in this position as well. 
Other modifications and variations can be made to the disclosed embodiment 
without departing from the subject of the invention as defined in the 
following claims. For example, trigger 42 could be a linear acting, rather 
than a pivotally acting element.