U.S. patent application number 11/656875 was filed with the patent office on 2007-11-01 for system and method for controlling pressure in a surgical tourniquet using a remote unit.
Invention is credited to Michael E. Hovanes, Don S. Schmitt.
Application Number | 20070255310 11/656875 |
Document ID | / |
Family ID | 26960197 |
Filed Date | 2007-11-01 |
United States Patent
Application |
20070255310 |
Kind Code |
A1 |
Hovanes; Michael E. ; et
al. |
November 1, 2007 |
System and method for controlling pressure in a surgical tourniquet
using a remote unit
Abstract
The present invention is a surgical tourniquet controller which
receives operational parameters from a remote unit, allowing flow
components associated with controlling a surgical tourniquet to be
collocated with a surgical tourniquet in use, while allowing an
operator of the tourniquet to operate the flow components from a
remote location, such as at an anesthesiologists position, thus
reducing the involvement of the surgical tourniquet operator from
the surgical field.
Inventors: |
Hovanes; Michael E.;
(Redmond, WA) ; Schmitt; Don S.; (Wauwatosa,
WI) |
Correspondence
Address: |
REED SMITH LLP
2500 ONE LIBERTY PLACE
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Family ID: |
26960197 |
Appl. No.: |
11/656875 |
Filed: |
January 22, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10290117 |
Nov 7, 2002 |
7166123 |
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11656875 |
Jan 22, 2007 |
|
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|
09504131 |
Feb 15, 2000 |
6475228 |
|
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10290117 |
Nov 7, 2002 |
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09280312 |
Mar 29, 1999 |
6051016 |
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09504131 |
Feb 15, 2000 |
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Current U.S.
Class: |
606/203 |
Current CPC
Class: |
A61B 17/1355 20130101;
A61B 34/10 20160201; A61B 2017/00199 20130101 |
Class at
Publication: |
606/203 |
International
Class: |
A61B 17/132 20060101
A61B017/132 |
Claims
1. A surgical tourniquet controller comprising: a flow controller,
said flow controller controlling the flow of a pressure medium into
and out of a surgical tourniquet; and a remote unit having a
display for displaying parameters associated with pressurization of
a pressure cuff and a data entry device for receiving operator
selections identifying desired operating parameters associated with
pressurization of a pressure cuff; wherein said remote unit is
remote from said flow control means and said remote unit is
communicably connected to said flow control means via a
communications path.
2. A surgical tourniquet controller according to claim 1, wherein
said display comprises a plurality of light emitting diodes, at
least a portion of said light emitting diodes arranged to display
values identifying the pressure in a pressure cuff.
3. A surgical tourniquet controller according to claim 1, wherein
said display comprises a flat panel display.
4. A surgical tourniquet controller according to claim 1, wherein
said display comprises a cathode ray tube on which a graphical user
interface may be displayed.
5. A surgical tourniquet controller to claim 1, wherein said data
entry device comprises a plurality of switches, wherein actuation
of one or more of said switches allows an operator of the remote
unit to indicate desired parameters.
6. A surgical tourniquet controller according to claim 1, wherein
said data entry device comprises a touch sensitive interface, said
touch sensitive interface extending over at least a portion of said
display, and wherein said touch sensitive interface allows an
operator of the remote unit to indicate desired parameters.
7. A surgical tourniquet controller according to claim 6, wherein
said touch sensitive interface is actuable by a stylus.
8. A surgical tourniquet controller according to claim 6, wherein
said touch sensitive interface is actuable by an operator's
finger.
9. A surgical tourniquet controller according to claim 1, wherein
said remote unit comprises a computer, said computer having a
display device, a pointing device, and a data entry device.
10. A surgical tourniquet controller according to claim 1, wherein
said communications path comprises a modulated electrical signal
for communicating information between said remote unit and said
flow controller.
11. A surgical tourniquet controller according to claim 1, wherein
said communications path comprises a modulated light signal.
12. A surgical tourniquet controller according to claim 11, wherein
said modulated light signal comprises a fiber-optic connection.
13. A surgical tourniquet controller according to claim 1, wherein
said communications path comprises a radio frequency communications
path.
14. A surgical tourniquet controller according to claim 1, further
comprising a second communications path communicably connecting
said remote unit and said flow controller.
15. A surgical tourniquet controller according to claim 14, wherein
said second communications path comprises a hardwired
communications path.
16. A surgical tourniquet controller according to claim 14, wherein
said second communications path comprises a computer network.
17. A surgical tourniquet controller according to claim 14, wherein
said second communications path comprises a modulated light
communications path.
Description
[0001] The present application is a continuation of U.S. patent
application Ser. No. 10/290,117, which is a continuation in part of
U.S. patent application Ser. No. 09/504,131, which is a
continuation of U.S. patent application Ser. No. 09/280,312. U.S.
patent application Ser. No. 09/280,312 issued as U.S. Pat. No.
6,051,016 on Apr. 18, 2002. U.S. patent application Ser. No.
10/290,117 issued as U.S. Pat. No. ______ on ______. The entire
disclosures of these applications are incorporated herein in there
entireties by reference thereto.
FIELD OF THE INVENTION
[0002] The present invention is directed to surgical tourniquet
controllers, and more particularly to surgical tourniquet
controllers having spatially separated operator control interfaces
and fluid pressure controllers to allow management of equipment and
operators adjacent to the surgical field.
BACKGROUND
[0003] Surgical tourniquets are used to provide a bloodless field
for surgical procedures involving the extremities of the human
body. The tourniquets function by compressing an extremity
sufficiently to collapse blood vessels in the area of the
tourniquet, thus preventing the flow of blood past the
tourniquet.
[0004] A tourniquet being used during surgery must be monitored by
a trained operator, typically an anesthesiologist. The function of
the anesthesiologist is not limited to monitoring the tourniquet,
but may also involve the administration of anesthesia to a patient,
as well as the monitoring of the patient vital signs during the
procedure.
[0005] Typically, the position of an anesthesiologist during a
surgical procedure is away from the surgical field. Although
surgical tourniquets are typically used on extremities, the
location of the anesthesiologist is adjacent to the head of the
patient, as shown in FIG. 1. This location generally assists in the
reduction of congestion in the surgical field.
[0006] Siting the location of the controller associated with the
surgical tourniquet is determined by the necessity to minimize the
amount of equipment located in the surgical field, while also
minimizing the length of the tubing necessary to provide a supply
of a pressure medium to the tourniquet cuff. Accordingly, the
surgical tourniquet controller is generally located near the
perimeter of the surgical field to limit the amount of tubing
required between the controller and a surgical cuff or cuffs.
Locating the controller adjacent to the surgical field, however,
also may require that an operator approach the surgical field to
operate the control interface of the controller.
[0007] Additionally, the proximity of the surgical tourniquet
controller to the surgical field results in the size and
configuration of the controller having an effect on procedures
within the surgical field. Reducing the size of the controller may
reduce the impact the physical proximity of the controller to the
surgical field will have, however may also adversely affect the
suitability of the operator controls, displays, or interface.
Finally, the configuration of the controller itself may be an issue
in ensuring cleanliness in the area proximate to the surgical
field.
[0008] In addition to the surgical tourniquet controller being in
the operating room when a surgical procedure using a surgical
tourniquet is being performed, other electronic equipment will
likely be present, such as EKG monitors, EEG monitors, breathing
monitors, and automated intravenous injection equipment, including
equipment being used to administer anesthesia. Much of this
equipment needs to be monitored to ensure its proper functioning,
typically by the anesthesiologist responsible for the
administration of anesthesia. If this equipment is distributed
throughout an operating environment, operator task loading may
increase unless additional personnel are provided. Including
additional personnel in the operating environment, however, may
also increase congestion for other personnel in the
environment.
[0009] Due to the sensitivity of the operating environment, the
potential of stray radio frequency emissions adversely affecting
other electronic equipment must be minimized. Excesses of cabling
may also be also undesired, due to the added complexity of ensuring
that the cabling is accurately routed and connected, due to
cleanliness issues associated with the cabling, and due to
potential impacts the cabling may have on the operating
environment, such as the creation of trip hazards.
SUMMARY OF THE INVENTION
[0010] The present invention is a surgical tourniquet controller
which receives operational parameters from a remote unit, allowing
flow control components associated with controlling a surgical
tourniquet to be located adjacent to with a surgical tourniquet in
use, while allowing an operator of the tourniquet to operate the
flow components from a remote location, such as at an
anesthesiologist's position, thus reducing the involvement of the
surgical tourniquet operator near the surgical field.
[0011] The present invention may be embodied in a surgical
tourniquet controller having a flow control unit located adjacent
to the surgical field, and a remote unit for providing an operator
interface to the flow control unit. The flow control unit may
include at least one pressure control valve for regulating the
pressure in a surgical tourniquet attached to the flow controller
via a channel allowing the transmission of a fluid (including
gasses). The regulation of the pressure in the surgical tourniquet
cuff may be accomplished by the valve opening to allow a higher
pressure medium to be exposed to the fluid channel, thus allowing
the higher pressure medium to enter the fluid channel, increasing
the pressure in the fluid channel. As the fluid channel is
connected to the pressure cuff, the pressure in the pressure cuff
will increase. The lowering of the pressure in the pressure cuff
may be accomplished in any of several fashions, including the
provision of a constant bleed-down condition, the provision of an
exhaust channel from a surgical tourniquet cuff to the environment
controlled by an exhaust valve, or by providing a pressure medium
recovery capability which recycles the pressure medium from a
surgical tourniquet cuff to the source of the higher pressure
medium.
[0012] The flow control unit may also include a communications
interface capable of receiving data from the remote unit. The data
may include information associated with an operating profile for a
surgical tourniquet. Minimally, the profile may include only a set
pressure, allowing control over the inflation of any pressure cuffs
attached to the flow control unit to be carried out by an operator.
The profile may include a duration as well as a set pressure. Other
information may be integrated into the profile to allow higher
automation of control of the surgical tourniquet, such as the
provision of threshold pressures which cannot be exceeded without
direct operator intervention, durations which can not be exceeded
without direct operator intervention, maximum pressures and
durations, and functionality for control of multiple pressure cuff
surgical tourniquets, such as those used in conjunction with
localized anesthesia within the surgical region.
[0013] The remote unit may include an interface to allow an
operator to control the profile of the surgical tourniquet. The
interface may merely allow the operator to provide a set pressure,
or may allow for the entry of complex profile parameters and the
display of surgical tourniquet operational conditions, such as
present pressure, display of any thresholds or maximum values,
display of any durations set or time remaining under a set
duration, or any other capability built into the flow control unit
or remote unit. Although the flow control unit and the remote unit
are contemplated as two separate devices, functions associated with
these devices may be disseminated across more than two physical
devices. An example of such a distribution would be the provision
of a flow control processor in a computer located remotely from the
surgical environment, while the operator interface and flow control
valving are distributed between two devices in the operating
environment. Accordingly, the remote unit also includes a
communications interface to allow information in the remote unit to
be transferred to the flow control unit, whether directly or
indirectly, such as through a distributed flow control
processor.
[0014] A pressure sensor may also be included in the flow control
unit, allowing determinations of present pressure to be made for
control purposes. Such a sensor does not need to be physically
integrated with the flow control unit, but merely needs to be able
to sense the pressure in a continuous volume of the pressure medium
which includes the surgical tourniquet pressure cuff.
[0015] The flow control processor converts desired profile
conditions into control signals for flow controls associated with
the flow control unit. The flow control processor may use the
output of the pressure sensor as a feedback to profile performance,
as well as may utilize information from other sensors as a means to
control surgical tourniquet performance.
[0016] The surgical tourniquet controller may also be embodied in a
system including a flow control means for controlling the flow of a
pressure medium into and out of a surgical tourniquet, and a remote
unit means. The remote unit means for identifying parameters
associated with controlling the operation of the flow control
means. The remote unit means is located remotely from the flow
control means, and is communicably connected to the flow control
means via a communications path.
[0017] Although the present invention may be embodied in a system
having a single operator interface located remotely from the flow
control unit (referred to herein as the "remote unit"), redundant
operator interfaces may be provided to reduce the potential impact
of the failure of a remote unit on an on-going surgical procedure.
A redundant interface may be provided on the flow control unit such
that in the event of a failure of a remote unit or communications
path, an operator may still successfully control the surgical
tourniquet from the flow control unit.
[0018] In a more complex embodiment of the present invention, the
surgical tourniquet flow controller may be embodied in a system
having a surgical tourniquet pressurization manifold The manifold
may have at least one pressure supply port and at least one
pressure control valve, allowing the pressure in a surgical
tourniquet connected to the manifold to be varied. A flow control
processor may be provided for controlling the at least one pressure
control valve in accordance with a pressure profile. The pressure
profile may be defined at least in part by a parameter defining an
operating condition of a surgical tourniquet The parameter may be a
duration, desired pressure, or maximum allowable pressure value.
The flow control processor may also include a communications
interface for receiving information entered into a remote unit or
other operating interface.
[0019] The present invention may also be embodied in a method for
controlling at least one surgical tourniquet pressure cuff. Such a
method includes the steps of providing a flow control unit adjacent
to a surgical tourniquet pressure cuff, providing an operator
interface remote from said flow control unit, providing a
communications path between the flow control unit and the remote
unit, receiving at the remote unit desired pressure cuff pressure
parameters from an operator, communicating the desired cuff
pressure parameters from the remote unit to the flow control unit
via the first communications path, and pressurizing the at least
one surgical tourniquet pressure cuff in accordance with the
desired cuff pressure parameters.
[0020] Other features and advantages of the invention will be
apparent from the following description of the preferred
embodiment, and from the claims. Accordingly, reference should be
made to the claims themselves
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 illustrates the layout of an operating room
configured for use in an operation involving placement of a
surgical tourniquet on a lower extremity of a patient, wherein a
surgical tourniquet controller according to the present invention
is implemented for controlling the surgical tourniquet.
[0022] FIG. 2 illustrates a notional operator interface for a
surgical tourniquet controller having a remote operator interface
unit.
[0023] FIG. 3 illustrates the components of an embodiment of the
present invention utilizing a hardwired connection as a
communications path.
[0024] FIG. 4 illustrates an embodiment of the present invention
utilizing a power distribution circuit as a communications path
between a flow control unit and a remote unit.
[0025] FIG. 5 illustrates an embodiment of the present invention
utilizing both radio frequency transmissions between a flow control
unit and a remote unit (and a hardwired communications path between
the flow control unit and the remote unit.
[0026] FIG. 6 illustrates an embodiment of the present invention
wherein a computer network is utilized as the communications path
to allow integration of the surgical tourniquet into the operating
environment, shown in FIG. 6 by the provision of an integrated ECG
monitor/remote unit, as well as the provision of a remote data
logger and remote anesthesiology monitoring station.
[0027] FIG. 7 illustrates the steps in a basic process for
controlling a surgical tourniquet according to the present
invention.
[0028] FIG. 8 illustrates an embodiment of the present invention
wherein the flow control unit includes a pressure generation source
to allow the use of a surgical tourniquet in conjunction with an
operating table not originally configured for use with a surgical
tourniquet.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Referring particularly to FIG. 1, wherein like numerals
represent like elements, there is shown a basic embodiment of a
surgical tourniquet control system (hereafter "STCS") embodying the
present invention. A flow control unit 102 and a remote unit 104
are provided. The flow control unit 102 (hereafter "FCU") may
include flow control valves for controlling the pressure in a
pressure cuff 106. Control circuitry for operating the valves may
also be located in the FCU 102. The remote unit 104 provides an
interface between an operator 102 of the surgical tourniquet
control system and the flow control aspects of the system.
[0030] As shown in FIG. 1, the remote unit 104 may comprise a
remote unit separate from the FCU 102 such that the remote unit 104
can be co-located with an anesthesiologist or other medical
personnel 108 (hereafter referred to collectively as the
"operator"). By providing the remote unit 104 at a location
co-located with the operator 108 (such as when the anesthesiologist
is the operator), the work load of the operator, when the operator
is responsible for equipment or procedures beyond the surgical
tourniquet, can be reduced by allowing the controls for the
disparate equipment to be placed in a single location.
[0031] The remote unit 104 may include a graphical user interface
202 such as the one shown in FIG. 2. This interface illustrates
some, but not all, of the indicators and controls that can be
associated with monitoring and controlling the functionality of the
FCU 102. The particulars of the graphical user interface selected
may depend on the possible functions that the STCS is capable of
performing. For example, where a timer is implemented into the
STCS, the graphical user interface may include a display 204
showing the time remaining until the timer times out. Where the
STCS incorporates flow feedback, as discussed in Applicant's
co-pending U.S. patent application Ser. No. 09/955,763, herein
incorporated in its entirety by reference thereto, the display may
incorporate displays 206, 208 associated with flow conditions, such
as whether flow is detected past a surgical tourniquet.
[0032] In a first embodiment, such as shown in FIG. 3, the FCU 102
and the remote unit 104 may be communicably connected through wires
302 which provide an electronic signal path between the units. The
remote unit 104 itself may be configured to allow it to be mounted
to an EKG display being used by an anesthesiologist, or may be
configured as a standard rack-mountable component allowing
incorporation of the remote unit 104 into a standard rack being
used to house other components used in the surgical theater.
[0033] The remote unit 104 may incorporate an output display 204 to
display parameters to an operator. The output display may be a
small flat screen display. A flat screen display may incorporate an
input device 306 such as touch sensing technology to allow
interaction between an operator 108 and the output display 304
allowing the operator to select operational modes or values through
interaction with the output display 304. Such a touch screen
generally senses the touch at a location using screen coordinates,
such as a touch at a certain row and column of the display.
Software associated with the graphical user interface may be used
to correlate the touch position with a control icon being displayed
at the time the touch was detected. Accordingly, the touch screen
can be used in coordination with the output display 304 to present
a variety of indicators and controls in a single unit. The remote
unit may also be provided with data logging capabilities, or data
output capabilities, such as a printer or writeable media
device.
[0034] The remote unit 104 may be configured such that it may be
attached to standard equipment pole, such as discussed in
Applicant's U.S. Pat. No. 6,051,016, herein incorporated in its
entirety by reference thereto. The FCU may be provided with a
pressure generation capability integral or may rely on an external
pressure source.
[0035] The FCU 102 and remote unit 104 may preferably be configured
with a minimum of surface features, such that the unit can be
readily cleaned and sterilized. Such a minimum of surface features
can be accomplished by limiting the presence of mechanical controls
such as toggle or slide switches on either unit. The use of a touch
screen assists in this endeavor.
[0036] Potential communication paths available for communicating
data and instructions between an FCU and a remote unit include
hardwiring, radio frequency transmission, and modulated light
transmissions. Each data communication path has benefits and
disadvantages when used in the surgical operating environment.
[0037] The simplest and likely most reliable method of providing a
communications path between the FCU and the remote unit is to
provide an electrically conductive wire 302 or wires between the
FCU 102 and the remote unit 104. The electrically conductive path
can be used to transmit modulated electrical signals from the FCU
102 to the remote unit 104, and vice versa. Technologies for
transmitting modulated electrical signals between the units are
known in the art, and generally incorporate some form of interface
310, 312 in each unit as shown in FIG. 3.
[0038] The use of a wired communications path may increase the
amount of wiring present in the operating room, potentially causing
trip hazards. Short circuits from frayed insulation, electronic
noise emissions from inductance associated with current flow
through the wires, and signal noise in transmitted signals (due to
wiring lengths receiving stray emissions within the operating room)
are other potential adverse consequences associated with the use of
a hardwired communications path. Additionally, the cable used as
the communications path must also be kept in a clean fashion, most
likely in a sterile condition.
[0039] Where a wire path for communicably connecting the remote
unit 104 to the FCU 102 is to be implemented, a power supply line
for the controller may be bundled with the control wiring to limit
the number of separate cables that must be present in the operating
room. The generation of electronic noise from a hardwired
communications path may be reduced by adequate shielding of the
cable used as a communications path. The communications protocol
used in the dedicated cable may be chosen for compatibility with
other electronic equipment in the operating environment, such that
the cable may function as a network bus to allow multiple pieces of
equipment to monitor the communications over the dedicated
cable.
[0040] Radio frequency (hereafter "RF") transmissions may be used
to alleviate concerns over the presence of additional wiring in the
operating room. RF transmissions can be accomplished in the
operating room environment using low power transmitters to minimize
the potential for effects between the emitted signals and other
equipment in the operating theater. The benefits of RF
transmissions as a communications path between the remote unit 104
and the FCU 102 are principally that the communications path does
not require either a direct line of sight between the remote unit
104 and the FCU 102, nor hardwiring which may become a hazard in
the operating theater.
[0041] RF transmitters, however, are direct sources of RF noise in
the operating room, and can adversely effect other electronic
equipment. Where combustible materials such as oxygen are in use,
RF transmissions must be maintained at minimal levels, to avoid the
creation of charge potentials in metal structures that could cause
static discharge. These problems can be minimized by the use of low
powered transmitters, sufficient to transmit over the short
distances necessary between the remote unit 104 and the FCU
102.
[0042] Modulated light communications paths may also be used to
transmit information between the Remote unit and the FCU, such as
using modulated infrared light emitters and light sensitive
elements in the Remote unit and FCU. The use of such technology is
known.
[0043] The use of modulated light, such as infrared transmission,
may be limited to line of sight, such that a visual path must be
maintained between the transmitter and the receiver. Visual paths
may also be susceptible to transient placement of objects between
the remote unit and the controller, such as personnel in the
operating theater, resulting in disruption of the communications
path between the remote unit 104 and the FCU 102. Such infrared
transmissions may also be limited in the data rate that can be
achieved due to longer dwell times necessary for accurate reception
of transmitted signals.
[0044] Alternately, modulated light can be transmitted using
fiberoptic cables, creating a hardwired communications path using
modulated light. Such a communications path has the advantage of
not generating electronic emissions from the cabling, but retains
the potential disadvantage of placing a cable in the operating
environment.
[0045] In light of the above concerns, it is presently preferred
that a hardwired communications path between the FCU 102 and the
remote unit 104 be utilized. The hardwired path may be either a
dedicated cable, or the use of a power cord where the
communications signals between the FCU 102 and remote unit 104 can
be imposed over the alternating current transmitted over the power
cord.
[0046] As shown in FIG. 3, a hardwired communications path 314 may
be provided between an FCU 102 communications interface 310 and a
remote unit 104 communications interface 312. A control processor
316 may be provided to interpret operational parameters entered by
an operator 108 (not shown) into a pressure profile at which a
surgical tourniquet pressure cuff 106 is to be operated.
[0047] An input device 306 may be provided with the remote unit
104, such that an operator 108 (not shown) can indicate desired
parameters. In a rudimentary form, the input device 306 merely
needs to allow an operator 108 (not shown) to indicate a desired
increase or decrease in a tourniquet pressure. The addition of an
output display 304 to indicate operating conditions associated with
the pressure cuff 106 allows the operator greater information upon
which to base operating decisions. Incorporation of additional
functionality into the FCU 102 or remote unit 104, such as but not
limited to, a timer, allows presentations of additional functional
constraints remaining to be displayed to an operator. Additional
functions are described in the copending applications and patent
incorporated herein.
[0048] The FCU 102 may also incorporate a relief valve 318 to allow
pressure in a pressure cuff 106 to be reduced when desired, as well
as a pressure sensor 320 to provide an indication of the occlusion
potential of a pressure cuff 106 connected to the FCU 102. As
occlusion of blood flow can be detected through dynamic monitoring
of pressure in the pressure cuff 106, a pressure sensor 320 is not
mandatory, but is rather a significantly useful capability.
[0049] As most operating rooms use clean or filtered power, ensured
by the provision of dedicated power filters/sources for the
operating room, the imposition of the communications signal over a
power cord may be used to reduce the number of cables in an
operating environment. Power cord transmission can be implemented
using available protocols, such as "HOMEPLUG", promulgated by
HomePlug Powerline Alliance, or through the use of a proprietary
protocol. The use of power cord transmission may be limited where
clean power is not provided in an operating room. In such a
situation, noise in the transmitted AC current may limit the
ability to clearly transmit signals from a controller to a Remote
unit. Such noise may be present due to other electronic equipment
utilizing the same power grid as a communications path, or from
noise generated by electrical motors using the same power grid.
[0050] A surgical tourniquet controller utilizing such a
communications path is shown in FIG. 4. The FCU 102 and the remote
unit 104 are both connected to the operating room power
distribution network 402, such that communications between the FCU
102 and the remote unit 104 can be accomplished by multiplexing a
signal coexistent with existing alternating or direct current. As
shown in FIG. 4, additional devices may also be connected to the
power network 402, allowing information from equipment such as, but
not limited to, ECG 404, EKG 406, and automated blood pressure
monitoring equipment 408 to be used to provide feedback to the
surgical tourniquet controller system.
[0051] As shown in FIG. 5, redundancies may be incorporated into
the system to provide increased reliability. Multiple
communications paths, such as an RF communications path 502 and a
hardwired communications path 504 (such as using electrical signals
or modulated light signals) may be provided such that loss of
communications over one path does not prevent operation of a
pressure cuff 106 from a remote unit 104.
[0052] Additionally, a redundant operator input device and output
display (not shown) may be provided for the FCU 102, such that in
the event of loss of communications over available communications
paths, control of a pressure cuff 106 may be accomplished from the
FCU 102. Such a redundant input and output capability may be a
limited capability sufficient only to provide a minimal
functionality, or be fully capable of controlling all functionality
associated with the surgical tourniquet controller system.
[0053] The present invention may also be embodied in the apparatus
shown in FIG. 6, wherein the FCU 102 is communicably connected to a
computer network 602. A network access device connected 604 to the
same computer network 602 is thus able to function as a remote unit
104 for the FCU 102, as well as to concurrently carry out other
functions in the operating environment, such as functioning as an
ECG or EKG monitor. Alternately, a network access device 606 may be
located remotely from the operating environment, and function as a
data logger, such that the network access device monitors the
pressures associated with a surgical procedure, as well as the
operator inputs, and the displays presented to the operator. Such a
data logging function may be used to monitor the performance of the
surgical tourniquet controller, as well as to allow correlation of
operator performance with patient conditions exhibited during a
procedure.
[0054] The use of a computer network as the communications path may
further allow the flow controller to integrated with other
equipment in the operating environment. Such a function is
described in co-pending application Ser. No. 09/955,763, which
teaches the use of remote cardiac function monitoring, such as, but
not limited to, automated blood pressure and respiration monitoring
equipment as feedback for performance of a surgical tourniquet.
Alternately, as described above, the integration into an operating
environment network may allow improved dissemination of surgical
tourniquet condition information to personnel dispersed throughout
a surgical theater, as well as located remotely from the surgical
theater, such as network device 608.
[0055] As shown in FIG. 7, the present invention may also be
embodied in a method for providing a surgical tourniquet,
comprising the steps of providing a flow control unit 702 adjacent
to the location of a surgical tourniquet being used, providing an
operator interface 704 remote from the flow control unit, and
providing a communications path 706 between the flow control unit
and the operator interface. An operator may then enter 708 desired
operating parameters for the surgical tourniquet into the operator
interface. The desired parameters are communicated 710 from the
operator interface to the flow control unit, where a surgical
tourniquet connected to the flow control unit can be pressurized
712 in accordance with the parameters. The parameters may be
transformed into a pressure profile based on the parameters, or the
parameters themselves may comprise the operating instructions to
the flow control unit, such as the minimalist increase/decrease
model discussed above.
[0056] The method may further comprise the step of providing a
second 714 or redundant communications path between the flow
control unit and the operator interface, such that should
communications over the first communications path be degraded or
lost, the second communications path may be used to ensure that an
operator may continue to use the operator interface to control the
flow control unit and surgical tourniquet pressurization.
[0057] When a second communications path is incorporated, the
method may include checking to determine whether communications
over a first communications path are available, such as by
conducting a periodic request to communicate between the flow
control unit and the operator interface to ensure that the
communications path is valid. It may be preferable to limit such
requests to periods when the flow control unit or operator
interface are turned on, such that a signal can be generated 718 to
alert an operator that communications between the flow control unit
and the Remote unit have been lost, or that one communications path
is not allowing communications.
[0058] The path checking function may also be implemented where
only one communications channel has been provided, however the
response associated with a detected loss of communications would be
limited to generating a signal to warn an operator of the lost
communications. Where redundant communications paths are
implemented, communications between the flow control unit and the
operator interface can be switched to a correctly functioning path
in response to the detected loss of communications. Additionally, a
signal can be generated under such circumstances, and a further
signal can be used if every communications path suffers a loss of
communications.
[0059] As is evident from the above description of the apparatus
embodying the present invention, the method can be expanded to
incorporate features associated with the disclosures of the
copending applications, such as the use of occlusion sensors, more
complex flow control systems, and feedback from ancillary equipment
such as, but not limited to ECG and EKG sensors, without departing
from the spirit or essential attributes of the invention.
[0060] As shown in FIG. 8, an additional benefit, such as embodied
in the implementation shown in FIG. 8, is the ability to use the
separation between the flow control unit and the Remote unit to
simplify retrofitting a surgical tourniquet system to operating
tables not originally configured for use with surgical tourniquets.
Such tables may lack a pressure source for generating pressure for
inflating a surgical tourniquet. Such tables will likely, however,
have some provision for providing AC power. By incorporating a
pressure generator 802, such as a small air compressor, into the
flow control unit 804, the flow control unit 804 may combine all
functionality required for supporting a surgical tourniquet.
Further, by using a remote unit 806, accessibility requirements for
the flow control unit are reduced, such that the flow control unit
may be placed underneath the table, and thus out of the way with
regard to the surgical field.
[0061] The present invention may be embodied in other specific
forms without departing from the spirit or essential attributes of
the invention. Accordingly, reference should be made to the
appended claims, rather than the foregoing specification, as
indicating the scope of the invention.
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