U.S. patent application number 12/819309 was filed with the patent office on 2010-10-07 for method of operating a drip sensor system in an enteral pump system.
This patent application is currently assigned to OST MEDICAL, INC.. Invention is credited to PETER J. SACCHETTI.
Application Number | 20100253515 12/819309 |
Document ID | / |
Family ID | 39499092 |
Filed Date | 2010-10-07 |
United States Patent
Application |
20100253515 |
Kind Code |
A1 |
SACCHETTI; PETER J. |
October 7, 2010 |
METHOD OF OPERATING A DRIP SENSOR SYSTEM IN AN ENTERAL PUMP
SYSTEM
Abstract
The present invention provides a method of operating an infrared
drip sensor in an enteral pump system to reduce false alarm
conditions. The method consists of the following steps: optically
coupling a infrared beam emitter with an infrared beam detector
along an infrared beam path that extends through a drip chamber and
intersects the drip path; monitoring the output signal of the
infrared beam detector to detect pulses; monitoring the pulses for
an interruption thereof; and running an infrared beam power update
routine when an interruption is detected in the pulses, the
infrared beam power update routine consisting of incrementally
increasing a power level of the infrared beam until the power level
of the infrared beam is sufficient to re-establish an output signal
at the infrared beam detector.
Inventors: |
SACCHETTI; PETER J.;
(ATTLEBORO, MA) |
Correspondence
Address: |
BARLOW, JOSEPHS & HOLMES, LTD.
101 DYER STREET, 5TH FLOOR
PROVIDENCE
RI
02903
US
|
Assignee: |
OST MEDICAL, INC.
Warwick
RI
|
Family ID: |
39499092 |
Appl. No.: |
12/819309 |
Filed: |
June 21, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
11954002 |
Dec 11, 2007 |
7767991 |
|
|
12819309 |
|
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|
60869386 |
Dec 11, 2006 |
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Current U.S.
Class: |
340/540 ;
250/338.1; 250/573; 417/53 |
Current CPC
Class: |
A61M 5/1689
20130101 |
Class at
Publication: |
340/540 ;
250/338.1; 417/53; 250/573 |
International
Class: |
G08B 21/00 20060101
G08B021/00; G01N 21/85 20060101 G01N021/85; G01J 5/00 20060101
G01J005/00; F04B 49/06 20060101 F04B049/06 |
Claims
1-4. (canceled)
5. A method of operating an infrared drip sensor in an enteral pump
system to reduce false alarm conditions, said method comprising the
steps of: (a) providing a drip chamber; (b) operating a pump to
move a fluid to said drip chamber wherein said fluid drips through
said drip chamber along a drip path; (c) optically coupling an
infrared beam emitter with variable output power with an infrared
beam detector with fixed sensitivity along an infrared beam path
that extends through said drip chamber and intersects said drip
path, said variable infrared beam emitter emitting an infrared
beam, said infrared beam detector generating an output signal
responsive to the absence of said variable infrared beam when power
of infrared beam is sufficient to be detected by infrared beam
detector when fluid is not dripping, (d) setting an initial power
level of said infrared beam sufficient to be detected; (e)
monitoring said output signal of said infrared beam detector as
said fluid drips through said drip chamber so as to detect pulses
in said output signal level, said pulses representing said fluid
dripping through said drip chamber; (f) monitoring said pulses for
an interruption thereof; and (g) running an infrared beam power
update routine when an interruption is detected in said pulses,
said infrared beam power update routine comprising the steps of
incrementally increasing a power level of said infrared beam until
said power level of said infrared beam is sufficient to
re-establish an output signal at said infrared beam detector.
6. The method of operating an infrared drip sensor in an enteral
pump system of claim 5 further comprising the step of: (h) shutting
off motor for pump when said output signal cannot be reestablished
after said infrared beam power update routine.
7. The method of operating a drip sensor in an enteral pump system
of claim 6 further comprising the step of: (i) triggering an alarm
when said output signal cannot be reestablished after said infrared
beam power update routine.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is related to and claims priority from
earlier filed provisional patent application Ser. No. 60/869,386,
filed Dec. 11, 2006.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to enteral pumps for
delivering liquid nutrition to patients who are unable to eat.
[0003] Enteral feeding pumps are used to supply liquid nutrition to
patients who are unable to eat. The pumping system generally
consists of the pump and a disposable tubing set for delivery of
the liquid nutrition. The tubing set is connected between a bag of
liquid nutrition and a patient's gastric line. A section of the
tubing set is seated on the pump housing where a rotor draws fluid
through the tubing set by peristaltic action.
[0004] A common design feature of enteral pumps is the ability to
detect the presence or absence of liquid flowing through the tube
set. This is typically accomplished by the detection of drops
falling within a transparent drip chamber portion of the tubing
set. In this regard, the transparent drip chamber is seated within
an opening in the pump housing where an infrared (IR) light source
(light emitting diode--LED) and infrared detector are positioned on
opposing sides of the drip chamber transverse to the liquid flow.
The IR beam passes through the drip chamber. When a drop of liquid
falls, it interrupts the IR beam and this interruption is converted
to an electronic pulse. The pulse presence and frequency are
processed by the pump firmware, which then either allows continuing
pump operation or stops the pump indicating one of several possible
alarm conditions, such as occlusion or excessive flow.
[0005] For the drop detection system to operate reliably, the IR
beam intensity must be set to a level that is sufficient to "see"
through the drip chamber walls, but not so intense that that the
beam is detected through the water drops without producing a
detection pulse. The IR beam power level is optimized for water,
since excess power can cause the water to be transparent to the
infrared beam, i.e. the beam is strong enough to pass right through
the water drop. Liquid nutrient is more optically opaque and thus
it can be detected with a wider tolerance of beam power level.
Because of this, water is the "standard" for calibration of the
detection power. For current pump design, the beam power level is
set to a fixed value that is intended to accommodate all variations
in electronics and materials used in the beam path.
[0006] False alarms are an undesirable consequence of fixed
sensitivity when the transparent wall of the drip chamber may
become less transparent through the accumulation of liquid residue
or droplets. These droplets are only a problem when they are
located in the path of the IR beam. Given enough operating time, it
is probable that a droplet will be situated in this manner. This
issue is more problematic for water due to its propensity for
droplet formation due to its high surface tension. Liquid nutrient
has a relatively lower surface tension and droplets dissipate more
readily once they impinge on the chamber wall. Water however, has a
tendency to stay in place longer and thus create a blocking
condition. With fixed infrared detector sensitivity, water droplets
will cause false alarms.
[0007] Typically, enteral pumps deliver only liquid nutrient to the
patient. In addition to the liquid nutrient, caregivers must also
give water to the patient, as the liquid nutrient contains
insufficient water for normal dietary requirements.
[0008] Several enteral pump manufacturers have produced pumps,
which are capable of pumping both liquid nutrient and water from
separate containers. A typical prior art design uses two separately
programmable peristaltic pumping motors, which are activated
according to a user program. Another method uses a single
peristaltic pump, and a tubing set having an integral two-way
valve. This valve is actuated by a second motor on the pump, and
thus controls that liquid source. Both of these configurations are
relatively high in cost because of the multiple motors.
[0009] In view of the foregoing, there is a desire for a less
expensive enteral pump system that includes only a single motor as
well as a method of operating an infrared drip sensor in an enteral
pump system to reduce occurrence of false alarms. It is also
desirable to provide a method of operating the infrared drip sensor
that automatically adjusts the infrared beam power according to the
current optical conditions. Further it is desirable to have a
method of automatically adjusting the infrared beam power of an
enteral pump system to accommodate water droplets and residue
within the drip chamber. Even further still it is desirable to have
a method of operating a drip sensor that can automatically
distinguish between water flow and liquid nutrient flow.
BRIEF SUMMARY OF THE INVENTION
[0010] The present invention preserves the well known advantages of
prior methods of operating an infrared drip sensor in an enteral
system but, in addition, provides new advantages not found in
currently available methods and overcomes many disadvantages of the
currently available methods for operating an infrared drip
sensor.
[0011] The present invention provides a method of operating an
infrared drip sensor in an enteral pump system to reduce false
alarm conditions. The method consists of the following steps:
providing a drip chamber; operating a pump to move a fluid to the
drip chamber wherein the fluid drips through the drip chamber along
a drip path; optically coupling a infrared beam emitter with an
infrared beam detector along an infrared beam path that extends
through the drip chamber and intersects the drip path, the infrared
beam emitter emitting an infrared beam, the infrared detector
generating an output signal responsive to the presence of the
infrared beam as the fluid drips through the drip chamber; setting
an initial power level of the infrared beam; monitoring the output
signal of the infrared beam detector as the fluid drips through the
drip chamber so as to detect pulses in the output signal level, the
pulses representing the fluid dripping through the drip chamber;
monitoring the pulses for an interruption thereof; running an
infrared beam power update routine when an interruption is detected
in the pulses, the infrared beam power update routine consisting of
incrementally increasing a power level of the infrared beam until
the power level of the infrared beam is sufficient to re-establish
an output signal at the infrared beam detector; shutting off the
motor for pumping when the output signal cannot be reestablished
after the infrared beam power update routine; and triggering an
alarm when the output signal cannot be re-established after the
infrared beam power update routine.
[0012] The present invention also provides a method for automatic
adjustment of the pumping rate of an enteral pump system according
to the type of fluid flowing through the pump system, the method
comprising the following steps: providing a first opaque fluid and
a second clear fluid for pumping; providing an enteral tubing
system that first allows flow of the first fluid and then flow of
the second fluid upon exhaustion of the first fluid; providing a
drip chamber; operating a pump at a first pumping rate appropriate
for the first fluid to move the first fluid to the drip chamber
wherein the first fluid drips through the drip chamber along a drip
path; optically coupling a infrared beam emitter with an infrared
beam detector along an infrared beam path that extends through said
drip chamber and intersects said drip path, said infrared beam
emitter emitting an infrared beam, said infrared beam detector
generating an output signal responsive to the presence of the
infrared beam as the first fluid drip through the drip chamber,
setting an initial power level of the infrared beam; monitoring the
output signal of the infrared beam detector as the fluid drips
through the drip chamber so as to detect pulses in the output
signal level, the pulses representing the first fluid dripping
through the drip chamber; at predetermined time intervals,
detecting the type of fluid being pumped by running a fluid type
check routine consisting of: counting a first number of pulses in a
predetermined period of time, increasing the power level of the
infrared beam by a predetermined amount, and counting a second
number of pulses in the same predetermined period of time, wherein
a comparison of said number of pulses determines fluid type;
operating the pump such that when the second number of pulses is
equal to said first number of pulses, said first pumping rate is
maintained, and further such that when the number of pulses are
unequal, said first pumping rate is changed to a second pumping
rate appropriate for the second fluid.
[0013] It is therefore an object of the present invention to
provide a method of operating an enteral pump with reduced
occurrences of false alarms.
[0014] It is a further object of the present invention is to
provide a method of automatically adjusting the infrared beam power
of an enteral pump system to accommodate water droplets and residue
within the drip chamber.
[0015] Yet another object of the present invention is to provide a
method of operating a drip sensor to distinguish between water flow
and liquid nutrient flow.
[0016] Other objects, features and advantages of the invention
shall become apparent as the description thereof proceeds when
considered in connection with the accompanying illustrative
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The novel features, which are characteristic of the method
for operating an infrared drip sensor in an enteral system, are set
forth in the appended claims. However, the method of operating an
infrared drip sensor in an enteral system, together with further
embodiments and attendant advantages, will be best understood by
reference to the following detailed description taken in connection
with the accompanying drawings in which:
[0018] FIG. 1 is a flow chart of the method for operating an
infrared drip sensor in an enteral pump system of the present
invention;
[0019] FIG. 2 is a cross-sectional view of a drip chamber used in
the method of FIG. 1 with fluid dripping there through to intersect
the infrared beam path;
[0020] FIG. 3 is an illustration of the amplitude of the pulse wave
during operation of the infrared drip sensor in FIG. 1;
[0021] FIG. 4 is a flow chart of the method for automatic
adjustment of the pumping rate of an eternal pump system according
to the type of fluid flowing through the pump system; and
[0022] FIG. 5 is schematic illustration of a two-source tubing set
for use in the method of FIG. 4 which provides both liquid nutrient
and water.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The present method solves a disadvantage of the prior art by
providing a new and unique method 10 for operating a drip sensor
system in an enteral pump system, which reduces false alarm
conditions.
[0024] As described in the background, an enteral pumping system
generally consists of a pump system 302 and disposable tubing set
for delivery of the liquid nutrition. The tubing set is connected
between a bag of liquid nutrition and a patient's gastric line. A
section of the tubing set is seated on the pump housing where a
rotor draws fluid through the tubing set by peristaltic action.
[0025] Generally, the pump system 302 comprises a controller 304,
pump motor 306, power source 308, and an infrared sensor system 350
containing an infrared beam emitter 380 and infrared beam sensor
360. See FIG. 6. The controller 304 is powered by the power source
308 and controls the pump motor 306 and the infrared sensor system
305. More specifically, the controller 304 instructs the pump motor
306 when to switch off/on based upon an output signal received in
the infrared beam sensor 360 which will be further described
below.
[0026] Referring to FIG. 1, a flow chart of a method 10 of
operation for the infrared drip sensor system in an enteral pump
system is illustrated. The method 10 generally comprises the
following steps as outlined below.
[0027] Referring to FIG. 2, a tubing system 420 and a drip chamber
320 are provided. The tubing system 420A, 420B connects at a top
end 320A and bottom end 320B of the drip chamber 320. The tubing
system 420A, 420B is similar to those known in the prior art. As
the pump 306 is operated, fluid 340 drips through the chamber 320.
The drip chamber 320 contains a wall 400, which is of a thickness
and color suitable for a penetration of an infrared beam. When
fluid 340 flows through the chamber 320, the fluid moves along a
defined drip path DP within the drip chamber.
[0028] Generally, the pump motor 306 has the capability of
different programmed rates of pumping of different types of fluid
340 to the drip chamber 320. For example, some fluids with higher
viscosity may require a higher pump rate while other fluids, like
water, may require lower pump rate settings. The pump motor 306
also has a run/stop switch capable of controlling the power to the
motor which pumps the fluid 340 through the tubing system 420A,
420B.
[0029] To begin operation of the pump 306, as shown in the method
10 of FIG. 1, the pump 306 is turned on with the pump motor 306 in
stop mode 20. Next, the pump motor 306 is turned on to a run mode
40 to move the fluid to the drip chamber 320 wherein the fluid
drips through the drip chamber 320 along the defined drip path DP.
The fluid drips through the drip chamber 320 at a flow rate
dependent upon the viscosity of the product, the configuration of
the drip chamber 320, and the programmed pumping rate based upon
the fluid flowing.
[0030] Referring to FIG. 2, to measure the rate of drops through
the drip chamber 320, an infrared sensor system 350 is used. The
infrared sensor system 350 includes an infrared beam emitter 380
and an infrared beam detector 360, which are optically coupled
along an infrared beam path BP that extends transversely through
the drip chamber wall 400 and intersects the drip path DP.
Referring back to FIG. 1, initially, the infrared beam power level
is automatically stepped up to a level that penetrates the walls of
the drip chamber 320. To calibrate the initial infrared beam power,
the infrared level can be manually or automatically updated before
each use. When the infrared beam emitter 380 emits an infrared
beam, the infrared beam detector 360 generates an output signal 430
responsive to the presence of the infrared beam as the fluid 340
drips through the drip chamber 320. As will be explained further, a
sample pulse wave of the output signal 430 is illustrated in FIG.
3.
[0031] After increasing an initial power level of the infrared beam
80, the output signal of the infrared beam detector 360 is
monitored 160 as the fluid 340 drips through the drip chamber 320
so as to detect pulses in the output signal level 430. The pulses
represent the fluid dripping through the drip chamber. As shown in
FIG. 3, when the infrared beam emitter 380 emits an infrared beam,
it establishes an output signal 430 in the infrared beam detector
360. At steady state operation, this is seen as a logic-hi 440A,
440B, 440C amplitude of the output signal 430. When the fluid 340
traveling along the drip path DP intersects the infrared beam path
BP, it blocks the infrared beam and interrupts the output signal
430 in the beam detector 360. These interruptions are seen as a
logic-low amplitude 460A, 460B. The pulsing of the amplitude from
high to low means that fluid 340 is dripping through the chamber
320. For each infrared sensor logic-low amplitude 460A, 460B, there
is a drop of fluid that passed along the drip path DP of the drip
chamber 320 and intersected the beam path BP. By counting the
number of sensor logic-low amplitudes 460A, 460B over time, the
number of drops of fluid 340 over time can be determined.
[0032] As long as there is an output signal 430 with a pulse 460A,
460B occurring periodically over a predetermined period of time 240
(drop pulse detected), the pump 306 motor continues to operate 180.
As discussed above, there are occasions when drops of the fluid 340
splash within the drip chamber 320 and cling to the drip chamber
wall 400. If these drops are located in the Beam Path (BP), they
will block the infrared beam and cause an interruption in the
pulses (constant logic-low). If there is an interruption of the
pulses 460A, 460B being monitored 240, there is a timeout 260 and
the pump motor 306 is turned off 70. The timeout may vary from
greater than or less than 3 seconds. Now, the infrared beam power
is reset at the initial setting 60 and an infrared beam power
update routine is run 80,160. Note, the timeout 260 will run a
predetermined number of times to re-establish an output signal in
the infrared beam detector 360. After the predetermined number of
times, the pump motor 306 turns off 280 and the alarm will sound
300.
[0033] The infrared beam power update routine 80,160 consists of
incrementally increasing a power level 80 of the infrared beam
until the power level of the infrared beam is sufficient to
re-establish an output signal at the infrared beam detector 160.
The infrared beam power update routine 80 will cause the infrared
beam power level to shift high enough to penetrate the drip chamber
walls 400 and any standing water droplets formed that block the
infrared beam. It should be noted the infrared beam power update
routine 80 may be performed automatically and continuously by an
algorithm.
[0034] When the output signal 430 of the infrared beam detector 360
is re-established after the infrared beam power update routine is
run 80, 160, the pump motor 306 turns on 180. The infrared beam
detector 360 continues to monitor the output signal 430 from the
infrared beam emitter 380 as the fluid drips through the drip
chamber 320 so as to detect pulses 460A, 460B in the output signal
240. When the delivery of all the fluid is complete 200, the pump
motor 306 is turned off 220.
[0035] After each increase of the infrared beam power level 80 and
a check of the logic state, the system checks if the maximum power
90 of the infrared beam is reached. If the maximum power of the
infrared beam is achieved 90 and the output signal 430 cannot be
re-established after a predetermined period of time 100, the pump
motor 306 is shut off 120 and an alarm is triggered 140. In this
manner, the method 10 of operation for the infrared drip sensor
system allows the pump 306 to run without interruption of false
alarms using the infrared beam power update routine 80, 160, but
yet alarm when actual alarm conditions are met 140.
[0036] Referring to FIG. 4, as a further improvement of the present
invention, a method 500 for operating an infrared drop sensor
system in an enteral pump system provides the ability to discern
the difference between water and liquid nutrient. This method 500
permits the pumping of both liquid nutrient and water at
user-programmed rates for each liquid. The method 500 for operating
an infrared drop sensor system contains the following steps.
[0037] Referring to FIG. 5, a first fluid 860 and a second fluid
840 are provided for pumping to the drip chamber 900. In one
embodiment, the first fluid 860 is a liquid nutrient or nutritional
supplement, which is typically opaque. The second fluid 840 is
water or other type of clear fluid. An enteral tubing system 800 is
also provided that first allows flow of the first fluid 860 and
then flow of the second fluid 840 upon exhaustion of the first
fluid 860. The enteral tubing system 800 will be described further
herein.
[0038] A drip chamber 900 is provided which allows for the flow of
the first fluid 860 and the second fluid 840 through the drip
chamber 900. The drip chamber 900 has all of the features and
advantages recited for the drip chamber 320 described above.
[0039] A pump 306 is provided which moves fluid through the enteral
tubing system 800 and to the drip chamber 900. The pump 306 has the
capability of having different pump rates depending upon the type
of fluid moving through the drip chamber 900. For example, when the
first fluid 860 is being pumped, a first pumping rate applies. When
the second fluid 840 is being pumped, a second pumping rate
applies. It should be noted that more than two fluids may be used
with more than one programmed pumping rate for each type of
fluid.
[0040] To begin operating the pump 306, as shown in the present
method 500 of FIG. 4, the pump 306 is turned on with the pump motor
306 in stop mode 510. Next, a pumping rate is programmed at a first
pumping rate 521 appropriate for the first fluid 860 to move the
first fluid 860 to the drip chamber 900 wherein the first fluid 860
drips through the drip chamber 900 along a drip path DP 520. In
addition, a pumping rate is also programmed for the second pumping
rate 522 appropriate for the second fluid 840 to move the second
fluid 840 to the drip chamber 900 wherein the second fluid 840
drips through the drip chamber 900 along a drip path DP 520.
[0041] Next, to begin operating the pump motor 306, the run button
is pressed on the pump 306, 530. The first pumping rate 521 of the
motor is set for the first fluid 860, 540. To measure the rate of
drops through the drip chamber 900, an infrared sensor system
similar to the infrared system 350 of FIG. 1 described above is
used. The infrared beam detector 360 of the infrared system 350
generates an output signal 430 which is responsive to the presence
of the infrared beam and generates a pulse 460A, 460B in the output
signal 430 as the first fluid 860 drips through the drip chamber
900 640.
[0042] Similar to the infrared system 350 of FIG. 1, after setting
an initial power level of the infrared beam, the output signal 430
of the infrared beam detector 360 is monitored as the fluid drips
through the drip chamber 900 so as to detect pulses in the output
signal. Note, if the first fluid 860 is opaque, the first fluid 860
will generate a pulse 460A, 460B in the output signal 430 as it
passes through the drip chamber 900 along a DP with little to no
sensitivity to the infrared beam power level. After a predetermined
period of time of pumping the first fluid 860 drips through the
drip chamber 900, a timeout occurs 550. If there are no pulses
being detected over a predefined period of time 640, known as a
drop error, the pump motor 306 is turned off 660 and the alarm is
sounded 680. If there are pulses being detected over a predefined
period of time, the pump motor 306 continues to run 540 at the
predetermined rate for the first fluid 860.
[0043] At predetermined timeouts 550, a fluid type check routine
runs to detect the type of fluid being pumped 560, 570, 580, 590,
600, 620. The fluid type check routine consists of counting a first
number of pulses A over a predetermined period of time 560. At
predetermined time intervals, a timeout is provided 570 after
counting the first number of pulses A. At predetermined timeouts
570, the power level of the infrared beam is increased by a
predetermined amount 570. In a preferred embodiment, the infrared
beam power level is increased to a level sufficient for penetrating
clear fluid such as water. At the increased power beam level, a
second number of pulses B over a predetermined period of time is
counted 590. At predetermined time intervals, a timeout is provided
600 after counting the second number of pulses B. At predetermined
timeout 600, the first number of pulses A is compared to the second
number of pulses B.
[0044] If the first number of pulses A is equal to the second
number of pulses B, and there is no drop error 640, the pump motor
306 continues to operate at the first pumping rate 540. Since the
first fluid 860 is opaque fluid such as liquid nutrition, the
increase in the infrared beam power level will not penetrate
through the fluid drop and thus will not increase or decrease the
number of pulses in the output signal. By measuring the pulses over
a defined period of time for two different infrared beam power
levels, and the pulses are the same, it indicates the first fluid
860 has not been exhausted and should continue to be pumped at the
first pumping rate.
[0045] If the first number of pulses A is unequal to the second
number of pulses, the pump motor 306 switches to a second pumping
rate for the second fluid 700. Since the second fluid 840 is clear,
an increase in the infrared beam power level will now penetrate the
water drops and change the number of pulses in the output signal.
Preferably, if the infrared beam power level is increased
sufficiently to penetrate second fluid 840 such as water, the
infrared beam will pass through the second fluid 840 at the higher
infrared beam power level. When measuring the second number of
pulses B at a higher infrared beam power level, the infrared beam
passes through the second fluid 840 so that fewer or no pulses will
be counted. As a result, the second number of pulses B for the
second fluid 840 will not equal the first number of pulses A. When
A is not equal to B, the second fluid 840 is moving to the drip
chamber 900 and a second pumping rate is turned on. By using a
first pumping rate for the first fluid and a second pumping rate
for the second fluid, the fluids, having different viscosity, can
be delivered at the appropriate or desired rates. Of course, this
method 500 may include more than two fluids and more than two rates
of delivery of the fluids.
[0046] After the second pumping rate of the pump motor 306 is
turned on for the second fluid 840, the pulses are monitored for a
drop error 720. If a drop error occurs, the pump motor 306 is
turned off 660 and the alarm will sound 680. If a drop error does
not occur, and no pulses are being received by the infrared
detector after a predetermined period of time, a check is run to
see if the delivery of the second fluid 840 is complete 740. If the
delivery of the second fluid 840 is complete, the pump motor 306 is
turned off 760. If the delivery of the second fluid 840 is
incomplete, the pump 306 continues to run at the second pumping
rate.
[0047] The pumping rate will therefore automatically adjust to the
programmed value, depending on the type of fluid flow. Thus, a
patient may receive 500 milliliters (ml) of food at 125 ml/hr,
followed by 500 ml of hydrating water at 290 ml/hr. The improvement
is realized with no hardware modifications of the standard enteral
pump, i.e. no additional pumping mechanisms, and with minimally
expensive tubing set.
[0048] Referring to FIG. 5, the method 500 for operating an
infrared drop sensor system in an enteral pump system utilizes a
single motor enteral pump 306 with the above-described drop sensor
system 350 and the tubing set 800 with two fluids, a first fluid
860 and a second fluid 840. Still referring to FIG. 5, these two
fluids 840, 860 are coupled together at a Y-port 880 above the drip
chamber 900. There is a low-cracking pressure check valve 835
(one-way check valve) in the second fluid tube that prevents
backflow into the second fluid supply 840. The first fluid supply
860 is maintained at a height, which is above the top of the second
fluid supply 840. This causes the check valve 835 to remain closed
as long as there is a first fluid and thus keeps the second fluid
from flowing. When the first fluid supply 860 becomes empty, the
second fluid supply 840 begins to flow.
[0049] In addition to the components listed above for the tubing
system 800, the following components are also part of the tubing
system: roller clamps 830, elastomeric peristaltic tube section
920, tube adapter 940, plastic tubing 960, fitting for patient
connection 980, and protective cap 1000.
[0050] Therefore, the present invention provides a method of
operating an infrared drip sensor in an enteral pump system 10. The
method of operating an infrared drip sensor allows for a reduction
in false alarms. The present invention also provides a method for
automatically adjusting the infrared beam power to accommodate
water droplets and residue within the drip chamber. In addition,
the present invention includes a method of operating a drip sensor
to distinguish between water flow and liquid nutrient flow.
[0051] It would be appreciated by those skilled in the art that
various changes and modifications can be made to the illustrated
embodiments without departing from the spirit of the present
invention. All such modifications and changes are intended to be
covered by the appended claims and the present invention.
* * * * *