Note: Descriptions are shown in the official language in which they were submitted.
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DISTRIBUTED SYSTEM FOR PATIENT MONITORING
AND REVIEW OF PATIENT DATA USING
TIME STAMPING AND NETWORK COMMUNICATION
FIELD OF THE INVENTION:
[0001 ] The present invention provides a distributed system for communicating
audio, video and medical data between patient monitoring sites, network
servers and
medical monitoring sites.
BACKGROUND OF THE INVENTION:
[0002] This invention generally relates to the field of medical signal
monitoring through a network. If the patient and doctor are located remotely
with
respect to each other, while connected to a network, then this circumstance is
often
referred to as telemedicine. If the doctor and the patient are located close
to each
oilier, perhaps within the same hospital building, then this is referred to as
conventional medical monitoring. In either case, the information from the
medical
signal acquisition devices attached to the patient can be communicated to the
medical
1110111tOrlllg site, and observed, reviewed, and analyzed by the doctor, by
means of a
network.
DESCRIPTION OF THE PRIOR ART:
[0003] PEIFI R et czl United States patent No. 5,987,519 issued November 16,
1999 teaches a packet-based telemedicine system which communicates video,
audio,
and medical data between a central monitoring station and a remotely
located~patient
monitoring station. A single transport/networlc layer is used for
encapsulating the data
in packets at the sending end, and for de-encapsulating the data at the
receiving end.
The system works essentially in real time.
[0004] BALLANTYNE et al. United States patent No. 5,867,821, issued
February 2, 1999, teaches a method and apparatus for electronically accessing
and
distributing personal health care data and services in hospitals and homes.
However,
the system requires interface between a pen-based computer (personal data
assistant).
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at each patient care station, each of which is interconnected through a master
library
to nursing stations and other resources.
SUMMARY OF THE INVENTION:
[0005] In accordance with one aspect of the present invention, there is
provided
a distributed system for acquiring, disseminating, and outputting audio,
video, and
medical data. The system comprises at least one patient monitoring site
comprising
a plurality of input devices by which selected audio, video and medical data
are
captured for a patient. There is at least one time server to provide a base
time signal
which is referenced by the plurality of input devices at each patient
monitoring site, so
as to provide a synchronized time stamp on all data captured by the plurality
of input
devices. Thus, each patient monitoring site is associated with a respective
time server.
[0006] There is also at least one medical monitoring site comprising at least
one output device at which audio, video and medical data can be selectively
output for
at least one selected patient monitoring site, in synchronization based on the
time
stamp. All of the data is communicated over a network, to which the plurality
of
input devices and the at least one output device are connected, so that a
selected
medical monitoring site may contemporaneously receive, review and analyze
synchronized audio, video and medical data from at least one selected patient
monitoring site.
[0007] In keeping with the present invention, at least one patient monitoring
site is located in physical proximity to its associated time server to ensure
accurate
synchronization o f the time stamp on all data captured by the plug ality of
input devices.
[000] Generally, the system is configured so that each patient monitoring site
further comprises at least one output device by which selected audio, video
and
medical data are output.
[0009] Still further, the system of the present invention provides for a
medical
monitoring site to further comprise at least one input device by which
selected audio,
video and medical data may be input so as to provide bilateral connnunication
between
the medical monitoring site and the patient monitoring site.
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[0010] In a more generally configured distributed system for acquiring,
disseminating, and outputting audio, video, and medical data, in keeping with
the
present invention, the system further comprises at least one intermediate
server for
selective storage of data captured by at least selected input devices from
selected
patient monitoring sites. This permits the review and analysis ofthe time
stamped data
at a time other than the actual instance when an event may occur. Thus, the at
least
one medical monitoring site may selectively output data for at least one
selected patient
monitoring site, in synchronization based on said time stamp, but at a later
time than
when the data is collected from the patient monitoring site.
[0011] Accordingly, a selected medical monitoring site may receive, review
and analyze stored synchronized audio, video and medical data from at least
one
selected patient 1110111tOrlllg site from said intermediate server, at any
selected time.
[0012] Still further, in a system in keeping with the present invention, there
may be a plurality oC intermediate servers, wherein each of the intermediate
servers
stores data from a selected specific input device at each patient monitoring
site.
[0013] Alternatively, when there are a plurality of intermediate servers, each
of the intermediate servers may be arranged so as to store data from a
selected group
of patient monitoring sites.
GENERAL DISCUSS10N OF THE PRESENT INVENTION:
[0014] At present the full complement of medical devices required for
continuous or periodic monitoring of complicated diseases like epilepsy are
not
available in one single unit configuration. In particular, medical signals
from the brain,
medical signals from the heart, medical signals associated with respiration,
medical
signals associated with pressures, medical signals associated with
concentrations of
chemicals, audio signals associated with the patient, and multiple video
camera signals
associated with the patient, are recorded independently of each other on
separate
electronic devices. It is desirable to link all of these signals together
exactly in time so
that each of the signals may be accurately correlated with the others.
[0015] In particular, in intensive care unit monitoring, cardiac care
monitoring,
epilepsy lllOllltOrlllg, sLlrglCal 111o111tOTlng, and sleep monitoring, among
other forms of
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so called "long term patient monitoring", the accurate recombination of these
signals
on one computer display, crt, or lcd, etc., facilitates the medical
practitioner with an
improved ability to diagnose the medical conditions associated with a
particular
patient. The limitation ofthe current art is that the individual medical,
audio and video
devices required to create a total description of the state of the patient at
any point in
time are not adequately connected and correlated on to another, in time. In
particular,
accuracy drifts in the master oscillators in each of the devices results in
large skews in
the "time" of the devices. '
[0016] For example, a commercially available video camera generating
continuous video data has been shown to drift by as much as plus or minus five
seconds worth of frames over a twenty four hour period. Relying on the number
of
video frames that were recorded by the video camera is not accurate enough,
without
periodically resynchronizing the medical system. Resynchronizing the system
has the
disadvantage of dropping some of either the medical information, or the video
or audio
information, to realign the data streams.
[0017] One method of overcoming this obstacle is to comlect each of the
medical, video and audio devices together through the same master computer so
that
the master computer can form data streams that consist of simultaneous
recording of
the medical, video or audio data to the server system. The disadvantage of
this
arrangement is that the processing ability of a single computer will
ultimately be
restricted by the processing power of the computer, or the network bandwidth
between
the computer and the network servers. In particular, if a playroom were
constructed
for the treatment of epilepsy patients, LlSlllg a large number of medical
devices, audio
devices and video devices for the continuous simultaneous observation of those
many
patients across the many cameras, one computer cannot process all of the
information.
Also, it may be desirable to allow the patients -- if they are children, in
the epilepsy
example being discussed -- to play without the encumbrance of being tethered
by
electronic cables to the computer. Wireless headboxes that acquire the medical
signals
and broadcast those signals to a storage server are desirable. In the same
way, patients
in different scenarios are encouraged to be ambulatory as part of the
procedure that
they are undergoing.
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[0018]' For example, a pregnant mother in labor may be encouraged to walls up
and down the halls of the hospital, or a person recovering from a heart attack
will
engage in walking in the hospital or a designated exercise facility associated
with the
hospital, as part of the recovery process. Further, it may be desirable in an
operating
5 theatre for an expert physician, such as a neurologist or neurophysiologist,
to monitor
the patient from outside the operating theatre. This arrangement may be
required for
reasons of sterility, convenience, or the desire to make the expert
physician's expertise
available to more than one operating procedure at the same time.
[0019] It may be desirable in many circumstances for there to be multiple
medical data streams and multiple camera views which are not restricted, so as
to form
independent teleconferencing views with the surgeon, the surgeon's assistants,
an
anaesthesiologist, operating room nurses, technologists, or other medical
personnel.
Likewise, video views of the surgical field, either external or internal
(laporascopic)
views, or video data views generated by microscopes, surgical head mounted
cameras,
etc., may be required during any given procedure. Of particular interest is
the process
of quantifying the relationship between interaction with neurological
structures of the
patient, and electrophysiological changes that may occur in the patient.
Another
excellent example of the eff cacy of the present invention showing the beneFts
thereof
over the existing art, is in the area of long term sleep studies for the
accurate diagnosis
of sleep apnea, and the like. Here, multiple camera views can be such as from
conventional video cameras, or the video views may be generated by specialized
imaging equipment such as fluoroscopy equipment, or imaging LlltrasOlllld
eqtllpmellt.
Thus, it is possible to have a conventional video view, a medical device
physiological
data view, and a video view from a specialized piece of medical imaging
apparatus.
In this way, adverse changes in the electrophysiology of the patient can be
accurately
correlated with actual anatomical configurations of the patient. For example,
an
occlusive blocking of the throat can be recorded by an ultrasound machine,
while at
the same time a wide angle view of the patient sleeping can record the sleep
apnea.
Moreover, the eeg data for the patient, his or her respiration, and cardiac
medical
signals, can provide simultaneous evidence of the changes.
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[0020] The present invention addresses the requirements of these scenarios and
many others by providing for a common time signal distributed to all of the
individual
devices associated with the patient monitoring site. Each of the devices can
then
digitize not only the medical, video or audio signal, belt it will also record
the time
information associated with the moment of digitization of every data sample --
or at
least some periodic number of digital samples -- such time coding being
embedded in
the data streams often enough to guarantee the accu r ate reconstruction of
the complete
medical information at a medical monitoring site. The medical monitoring site
may be
located inside the patient monitoring area or remotely, and it may be
connected by
TCPIIP protocols to intermediate servers, to the networlc, and to other
patient and/or
medical monitoring sites.
[0021 ] For these examples, and many others where the medical system needs
to maintain high accuracy synchronization over a long term among many video,
audio
and medical data sources, the technique of counting frame information or
digitized
sample count cannot be used to accurately synchronize the information at a
patient
monitoring site. The present invention allows for the writing of medical,
audio or
video data from independent devices with time synchronization information
encoded
in the data, such time synchronization information being provided to all of
the devices
that make up the total of the devices in the patient monitoring site by an
independent
time server which broadcasts time information to all of the devices in the
patient
monitoring system. Alternatively, one of the devices in the patient monitoring
system
may assume the role of master time server, and it will broadcast time
information to
all of the other devices in the medical system associated with that patient
monitoring
site. Such time information can be broadcast to all of the devices by suitable
network
means including but not restricted to a LAN (local area network), WAN (wide
area
network), internee, intranet, extranet, wireless area network, wireless LAN,
cable TV
network, aSyllchroIlOLIS transfer mode network, public switched telephone
network,
integrated services digital network, infrared network, microwave relay
network,
satellite network, or any other type of networlc capable of transmitting
packets
formatted in TCP/1P protocol.
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[0022] The patient monitoring site can be comprised of a great many data
acquisition devices including but not limited to video, audio and medical
content
devices such as ecg, respiration, eeg, blood pressure and rate, temperature,
etc.
Further, multiple data acquisition devices of the same type, for example but
not
restricted to, multiple video cameras, can be connected at the patient
monitoring site.
Each data acquisition device is in communication with each of the other
devices at the
patient monitoring site to maintain time synchronization between all the
devices. Each
data acquisition device can format its data in TCP/IP protocol, but that fact
is not
germane to the present invention.
[0023] It is useful to not have to accumulate all of the audio, video and data
streams into a single communication stream. For example, video and audio of
the
patient may be gathered and transferred to an intermediate server via a high
speed
networlc lilce a LAN or DSL, while the patient medical data may be transmitted
to an
intermediate server by a low speed wireless network such as CDPD, CDMA or
infrared. This allows to the patient the important mobility required to
perform their
normal tasks without being tethered to a machine.
[0024] Because patient ambulation is a critical part of the recovery process,
and
mobility is desired in many hospital or remote homecare monitoring settings,
the
medical system does not require independent audio, video or medical devices to
be
hard wired together. The data, because it is time stamped, does not need to be
aggregated~into one control unit for communication to the intermediate servers
via one
networlc pathway. Independent data streams from each of the audio, video or
medical
devices can be communicated to one or several intermediate servers, which can
be
located anywhere on the Internet, via TCP/IP over independent network
pathways.
The data stream from each independent audio, video or medical device contains
time
information allowing the data to be resynchronized at a later time at the
medical
monitoring site.
[0025] Resynchronization is critical, because medical physiology must be
identically correlated with video movement in for example the field of
epilepsy
diagnosis. As one of many possible examples, small patient worn medical
devices can
transmit information to respective intermediate servers directly through
wireless
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connection to the Internet, while high bandwidth devices such as video cameras
can
simultaneously transmit information over higher bandwidth land lines to the
same or
different intermediate servers. A further advantage is that multiple
synchronized
audio, video and medical data feeds may be added to provide to remote medical
_, 5 practitioners more complete information about the current state of the
patient. An
example where this is important is in remote operating room monitoring, where
multiple independent camer as can provide simultaneous views from, but not
restricted
to, a face view of the surgeon for teleconferencing, a wide angle view of the
surgical
field, a close up view of the surgical field through a microscope, and views
from
laporascopic cameras, all perfectly synchronized in time with the
electrophysiological
monitoring devices connected to the patient.
[0026] Another important example is when multiple high bandwidth video
streams from different cameras are written independently to an intermediate
storage
server, while medical data streams are also being written independently across
the
same or different networlc path. The medical monitoring site can be configured
to
display the appropriate video stream that shows the most relevant view of the
patient,
having regard to the medical data being viewed.
[0027] Because the patient monitoring site does not have to provide storage or
display of the medical signals, the medical devices at the patient monitoring
site can
be made extremely simple. A patient monitoring site medical device can consist
of a
medical transducer, an analog to digital converter, and a small cpu to control
the
digitization and transmission of the data to the network. Software to store,
process and
display the data does not need to be located at the patient monitoring site or
the
medical monitoring site, but can be stored independently on intermediate
servers that
are connected to the network. This software can be uploaded from one or
several of the
intermediate servers at the time the particular data stream is chosen for
review. This
is advantageous for many reasons: software can be managed cents ally so each
individual medical monitoring site will always have the latest version of
software
without a difficult maintenance effort; further, the institution benefits
because this
software is available to all potential medical monitoring sites, including
ordinary PC's.
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[0028] Another distinct advantage of the present invention is that the
hardware
for the processing and storage of many types of medical signals can be
replaced by
intermediate servers. Even more flexibility is achieved when individual
medical
devices are connected directly to the networlc, time synchronized with other
devices
on the network, and generate independent data streams. In fact the
aclcnowledgement
of the storage operation by linked software can trigger other events. Data may
be
analyzed, the results of that analysis directed to either the medical
monitoring system,
the patient monitoring system, or an administrative system for appropriate
action.
Further, the ability to encode time information with or into the medical data
stream
itself allows many independent medical devices to feed their data to
independent files
located on independent servers. The medical monitoring site can retrieve the
data from
many different locations and create a new medical montage. In a multi-modality
setting, cardiac, eeg video, ultrasound, blood pressure data, among other
feeds, can be
displayed on the same screen, thereby providing the opportunity for the
medical
practitioner to determine causality between the changes in one medical signal
with
another. For many tasks such as recording a blood pressure, taking a
temperature,
among others, are in fact providing documentation for the respective patient.
[0029] Because the intermediate servers are readily accessible from the
patient
monitoring sites, many tasks that previously were not digitized directly can
be
affordably integrated into the electronic medical record. A further advantage
of the
present invention is that the common infrastructure may be leveraged across
many
medical, audio or video acquisition devices, allowing additional devices to be
added
to the patient monitoring site at a fraction of the cost of conventional
dedicated
medical instruments. Another advantage of the present invention is the ability
to
develop time synchronized views of many modalities that are usually recorded
in
completely independent locations, and which are generally not well correlated
with one
another. An excellent example is when the volume and time of delivery of a
drag by
a networleed drug.delively device forming part of the patient IllollltOrlllg
system is
synchronized with an electrophysiological recording of the physiological
parameters
that the administered drug is meant to influence. Correlations between changes
may
be more easily observed.
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[0030] Any medical monitoring site can connect through TCP/IP network
protocols to one or several intermediate servers, and can request one or
multiple data
streams from files generated by devices located at the patient monitoring
site. The
high speed of networks and intermediate servers results in only a slightly
delayed view
5 of the patient monitoring site information.
[0031] A further distinct advantage of the system is that multiple caregivers
can comiect to the salve patient at the same time, by simultaneously
connecting to the
intermediate servers. In this way, independent doctors and telehealth nurses
may
perform a simultaneous medical consultation without overloading the
communication
10 capacity of any of the audio, video or medical devices located at the
patient monitoring
site. A further advantage of the system is that the data is automatically
archived to an
intermediate server or servers in real time.
[0032] In some circumstances, multiple medical students may be observing'a
patient for instructional purposes, for example. Then, it is desirable to
connect directly
to the patient without excessively burdening the server. In this circumstance,
it is
desirable to utilize simultaneous broadcast protocols like UDP, (universal
datagram
protocol), so that broadcast communication about an individual patient
monitoring site
can occur to many medical monitoring sites.
[0033] It is extremely important that all of the medical, audio and medical
data
feeds be time synchs onized for review, so as to be able to accurately analyze
the cause
and effect relationships between the data streams. In particular, if the data
streams take
different paths through the network to different intermediate servers, the
time
information must be properly encoded in the data stream at the source before
the
transmission to the network or accurate re-assembly of the information will
not be
possible.
[0034] Thus, the present invention provides a medical system for transmitting
time coded audio, time coded video, and time coded medical data between
patient
monitoring sites and medical 1110111tOTlllg sites by means of network
communication,
and usually through one or several intermediate storage and broadcast servers.
[0035] One or several control units can be located at each patient monitoring
site, the control units receiving video, audio, and medical data from one or
more video,
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audio, and medical monitoring devices in communication with the control units.
The
control units receive time data from a time server in communication with the
respective control units. The control units encode time information with the
video,
audio, and medical data, and then deliver the time stamped data to
communication
devices in communication with the control units. Generally, the communication
devices will then encapsulate the time stamped data into packets in accordance
with
a preselected communication protocol, and output the packets onto a network.
The
time stamped data may be sent for storage on an intermediate server, or it may
go
directly to a selected medical monitoring site, or both events will generally
occur.
[0036] A network connection is provided between the communication devices
in communication with the audio, video and medical device control units, to
allow
time stamp information to be communicated between the respective control
units.
[0037] A plurality of medical monitor control units are located at one or more
medical 1110111tOrlllg sites, the control L1111tS being in COI11111L1n1Catloll
Wltll a
communication device. The communication device selectively requests and
receives
time stamped data packets from one or more intermediate storage servers on the
network. The task of the communication device is to de-encapsulate the time
stamped
data packets to reconstruct time coded medical, audio and video data from one
or many
control units at the patient monitoring site.
[0038] There may be one or more intermediate servers connected to the
network, which receive, store, retrieve and transmit the time coded audio,
video or
medical data.
[0039] Medical monitoring site control Lllllt software is provided to
construct
time synchronized representation of data from one or many medical device
control
L1111tS for further display or processing purposes.
BRIEF DESCRIPTION OF THE DRAWINGS:
[0040] The novel features which are believed to be characteristic of the
present
invention, as to its structure, organization, use and method of operation,
together with
further objectives and advantages thereof, will be better understood from the
following
drawings in which a presently preferred embodiment of the invention will now
be
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illustrated by way of example. It is expressly understood, however, that the
drawings
are for the purpose of illustration and description only and are not intended
as a
definition of the limits of the invention. Embodiments of this invention will
now be
described by way of example in association with the accompanying drawings in
which:
[0041 ] Figure 1 is a general schematic of a distributed system in keeping
with
the present invention; and
[0042] . Figure 2 is a further general schematic showing an alternative
distributed system in keeping with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0043 J Referring now to Figure l, a typical arrangement of a distributed
system
in keeping with the present invention is illustrated. Here, the major
components
comprise a patient monitoring site 12, a typical medical monitoring site 14, a
typical
intermediate server 16, and a communication networl:18. Generally, any
distributed
system in keeping with the present invention will comprise a plurality of
patient
monitoring sites 12; and as shown, it will also comprise a plurality of
medical
monitoring sites 14a through 14n, and a plurality of intermediate servers 16a
through
16n. Each medical monitoring site 14 includes at least one output device 15.
Each
patient monitoring station 12 includes an output control device 17, by which
selected
audio, video and medical data are output; all as noted hereafter.
[0044] Within the patient monitoring site 12, there may be a plurality of
input
devices by which selected audio, video, and medical data are captured for a
patient.
Audio capture devices are shown at 20a through 20n; video capture devices are
shown
at 22a through 22n; and medical data devices are shown at 24a through 24n. A
time
server is shown at 26, and it provides a base time signal which is referenced
by all of
the input devices so as to provide a synchronized time stamp on all the data
captured
by the plurality of 111pL1t devices - all of which data is then OLltpllt
through all Olltpllt
control device 17 to the network 18, through a plurality of networlc
connections shown
generally at 3 0.
[0045] Also shown in the patient monitoring site 12 are an audio playbaclc
control unit 32 and a video display control unit 34. These permit bilateral
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communication between any input device 19 at any medical monitoring site 14
and the
patient monitoring site 12, so as to provide for communication between a
doctor or
other caregiver who may be located at a medical monitoring site 14, and the
patient
who is located at the patient monitoring site 12.
[0046] Thus, audio, video and/or medical data can be selectively output from
any medical monitoring site 14, at its respective output device 15, for at
least some
selected patient monitoring site 12, in synchronization based on the time
stamp from
the time server 26.
[0047] Figure 2 shows another general layout for a distributed system in
keeping with the present invention. IIere, there are a plurality of patient
sites 12a
through 12n; and the time server 26 is shown as being separately located away
from,
and thus not part of, any individual patient monitoring site 12. However, the
time
server 26 is in close physical proximity to the patient monitoring sites 12 so
as to
ensure accur ate synchronisation of the time stamp on all data captured by the
plurality
of the input devices at the plurality of patient monitor ing sites. Put in
other words, the
close proximity of the time server 26 through the patient monitoring sites 12
precludes
the likelihood of any delay artifacts that might otherwise occur as a
consequence of
network transmission of packetized, encapsulated data.
[0048] Also shown in the distributed system illustrated in figure 2 is an
administrative site 40. The administrative site 40 may serve a number of
different
purposes; included among them may be the maintenance of patient billing
records and
the like. The administrative site may also be such as to allow for the
intervention of
a supervisory caregiver who might, for example, have the option of initiating
drug
administration to a patient at a patient site using bilateral communication
with a drug
administration device of some sort located at the patient monitoring site.
[0049] Other modifications and alterations may be used in the design and
manufacture of the apparatus ofthe present 111Ve11t1011 WlthOtlt departing
from the spirit
and scope of the accompanying claims.
l3
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[0050] Throughout this specification and the claims which follow, unless the
context requires otherwise, the word "comprise", and variations such as
"comprises"
or "comprising", will be understood to imply the inclusion of a stated integer
or step
or group of integers or steps but not to the exclusion of any other integer or
step or
group of integers or steps.
14
