Therapy monitoring and
personalised mediciney
Intravenous catheters infuse drugs into the body and can send back information about the effects of
the infusion so that the drug therapeutic index can be increased by controlling infusion parameters.
Alexandre Tsoukalis, Micrel Medical Devices, describes an alternative way to trial phases
of a drug where its dose prescription depends on the feedback reading, not on age and weight.
Today’s practice is to infuse drugs
unattended, based on an early clinical
study that specified a ‘blind’ prescription
rule. There is no real time reported feedback on
therapy results or side effects, so it is necessary for
doctors to change the protocol or drug as early as
possible. It is obvious that if the side effects can
be observed/measured by a return route
while a drug is infused:
- casualties caused by medication error
can be prevented
- the side effects of a patient who is borderline
for the drug can be prevented by reducing
or stopping infusion before the side effects
become dangerous and so the toxic limit
for the patient’s genotype can be found
- drugs that have metabolic effects depending
on living conditions (like insulin) can be
administered safely.
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The Rythmic Connect pump allows
infusion parameters to be changed
within predefined limits. |
Micrel Medical Devices’ Rythmic pump has
the ability to let the nurse, automatic pump
process or distant server change certain infusion parameters
within predefined limits. These parameters can also be changed
by the doctor over the internet by using a safe telemetry
process. The method used by medical personnel is the
automatic process of ‘trimming within limits’ preset by the
doctor. The pump, being a class IIb medical device, is
considered reliable to observe these limits and so excessive
over or under-infusion can be prevented.
Side effects can be identified by placing sensors in the
implantable catheter tip used in many chronic diseases in the
bloodstream (to read states such as temperature, blood pressure,
glucose, oxygen and ions) or by the pump asking the user about
conditions such as diarrhoea, vomiting and nausea.
Should an automatic process correct the pump dosage, if the
pharmaceutical company needs to keep the closed loop algorithm
proprietary, the algorithm can be located in a server under its
control and output communicated to the pump through telemetry.
Telemedicine service
MicrelCare™ is a telemedicine service based on GSM/GPRS
telemetry connecting Micrel’s ambulatory Rythmic Connect
pump and sensors to its micrelcare server. The server web
pages are used by the home-care provider/hospital service and
have data about patients treated and nurse
personnel organised in groups. So a nurse who is
in charge of a patient will receive an SMS
describing the problem encountered with the
pump or the treatment, or be informed that in
a given time the drug reservoir must be
replaced. From a list of patients, doctors and
paramedics can watch the infusion (events
and graphs) and therapy progress of each
patient in real time on the web, with alarms
in red popping up in the list.
Technically, this is possible as follows: the
Rythmic Connect pump is connected serially
with Micrel’s IP-Connect proprietary mobile
GSM/GPRS data phone, which is permanently
connected with the micrelcare server, while
communicating by a radio link (such as Bluetooth
but ultra-low power), to other personal health devices
on the patient, in the form of a personal area
sensor network. Micrel Medical Devices holds
European and US patents for this technology.
Web-programmable ambulatory pump
Micrel’s new Rythmic i-PCEA, the first CE Marked webprogrammable
ambulatory pump, is an example of feedback used
for therapy enhancement. Regional analgesia uses a catheter
placed adjacent to a nerve block. Pump programming has a lot to
do with the distance of the catheter to the nerve and the elapsed
time. The doctor rarely knows the correct programming of a
regional analgesia pump, so many patients stay at the hospital
until the doctor finds a working protocol. With the Micrel
solution, doctors can send the patient home, the patient
answers questions about the motor block or analgesia results
and then the doctor trims the protocol through the internet.
The system is completely ambulatory acting as an ICU for
working and ‘normal-living’ patients. It has the power to
change the way drugs are registered, and even revitalise drugs
rejected from the clinical trial process in a personalised
medicine approach. The system also adds compliance and
validity on clinical trials processing.
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