Biomedical Engineering Reference
In-Depth Information
Information collection and clinical
information systems
Not all ICUs are managed the same way. There are two
prevailing schools of thought regarding this issue. In some
hospitals, when a patient is admitted to the ICU, most, if
not all, of the patient's subsequent medical management
is in the hands of a dedicated staff of intensive care
specialists (IC specialists) whose responsibilities lie pri-
marily in the ICU environment. This team of specialists
includes physicians with specialties in such areas as pul-
monary, cardio-vascular, infectious diseases, and internal
medicine. Additional medical specialties are consulted as
needed. Control of the patient's care is usually relin-
quished by the referring physician or surgeon. In other
institutions, the referring physician might continue to
monitor and adjust the therapy to the patient with the
assistance of specialized nursing staff and technicians.
The prevailing literature indicates that there may be
benefits in terms of improved ICU survival rates, reduced
length of stay, and a decrease in operating costs in an IC
specialist-controlled ICU model.
The availability of this vast array of data and diagnostic
tools does not necessarily translate into better outcomes
for ICU patients. The complexity of a particular patient's
condition makes the interpretation of the data a less-
than-automatic or intuitive process. Additionally, clinical
studies that challenge certain prevailing ICU practices
are constantly emerging in the literature. The relatively
wide latitude of patient response to, and tolerance of,
interventional procedures further clouds the issue. It
cannot be stated with any clear degree of certainty that
the introduction of advanced monitoring, therapies, and
data management technology has resulted in a definitive
decline in patient mortality. What advanced information
technology has provided, however, is a streamlining of
the information assembly process. This simplifies and, to
some extent, reduces the time required to assess and
begin treating the patient.
Most, if not all, health care facilities in the 21st century
have installed an information systems (IS) infrastructure
that permits the dissemination of all manner of in-
formation to the hospital staff. Computer workstations
are inexpensive and widely available, and they tap into
the institution's high-speed networks. Thus, ICU staff
accessibility of such data as patient medical records and
test results is assured.
As the patient is admitted to the ICU, information
from his medical history and ongoing monitoring are
collected and correlated. In today's modern facility, a vast
array of information is available to assess the patient's
condition. To this end (in addition or as part of the
bedside monitoring), high-speed data networks route
a large volume of information to the bedside for analysis.
Past ECGs are retrievable from archived records and can
be compared with the latest 12-lead ECG available at the
bedside. Blood chemistry values are obtained, and rele-
vant radiological and ultrasound images are retrieved
electronically by way of a picture archiving and com-
munications system (PACS) that is available for viewing
near the patient's bedside.
The actual display devices for physiological monitoring
and patient lab data are often identical. Increasingly, there
has been a movement away from proprietary CRT mon-
itors or thin screen displays in physiological monitoring.
Many manufacturers have begun to use components and
interfaces that are commonly and inexpensively available
in the IS industry. Additionally, digital information is
transacted using standard Ethernet protocols. This allows
a certain degree of compatibility between physiologic
monitoring systems and the patient's medical records. In
many instances, parametric information from physiologic
monitoring system passes to clinical information net-
works and workstations. To varying degrees, laboratory
data are viewable on the physiologic monitors.
Therapy
Patients who have been admitted to the ICU present with
a host of problems that might or might not be life
threatening. Severe dehydration, chest pain, and short-
ness of breath are common symptoms that dictate ICU
entry. Upon admission, monitoring of basic vital signs is
begun immediately and includes the measurement of
ECG (Plonsey, 1988), NIBP (King, 1988), and arterial
blood-oxygen saturation (S
a
O
2
) (Welch et al., 1990). The
resulting parametric information points to the first ther-
apeutic interventions. Disturbances in the heart rhythm
and rate are immediately visualized, blood pressure in the
abnormal range identified, and low levels of S
a
O
2
addressed. A peripheral intravenous (IV) line is started
for the administration of medications, fluid support, and
withdrawal of blood samples for diagnostic evaluation.
Interpretation
To address conditions that are life threatening and that
require immediate intervention, several algorithms have
been developed that, to a certain degree, address
a given acute clinical situation. These algorithms can be
taught to newer ICU staff and compensate to some
extent for the experience that otherwise would be re-
quired. This distills the array of information into
a simplified set of required parameters to treat a spe-
cific situation. A decision tree is followed with feedback
information that is derived from the monitoring and
diagnostic equipment.
