Cardiopulmonary bypass technologies - Biomaterials and Devices for the Circulatory System - page 155

widespread research activity in this area was established. Today, in CPB,
there appear to be several opportunities for the application of biosensor
technology to the pre-, peri- and post-operative monitoring of patients. A
major opportunity to improve clinical intervention might become available
if fast near patient instruments or in vivo sensors for infl ammatory markers,
such as the interleukins, were to be made available for continuous or fre-
quent monitoring of patients in the peri- and post-operative periods. This
would allow much more accurate profi ling of infl ammatory markers during
and after CPB, which could provide important early warning systems for
potential outcomes and/or the need for increased intervention during or
following CPB. 31 Biosensor opportunities exist for CPB, but require sound
research and development investment to bring them into regular use. The
further miniaturization of devices and molecular manipulation possibilities
created by advances in nanotechnology are expected to further enhance
medical treatments. Exploitation of nanotechnology for medicine is likely
to take many forms, but it is already clear that the facilitation of multidis-
ciplinary interactions between engineers, life scientists and clinicians will be
fundamental to introducing real advances in patient monitoring and
treatment.

6.6 Novel monitoring devices for safety in
cardiopulmonary bypass
The key objective of point-of-care testing, otherwise referred to as near
patient or bedside chemical testing, is to generate a result quickly so that
appropriate treatment during acute care can be implemented, leading to an
improved clinical and/or economical outcome. Especially during CPB for
cardiac surgery, close monitoring of blood gas, electrolytes, lactate and
glucose is essential for maintaining physiologically acceptable conditions.
These parameters are subject to rapid dynamic change, making the turn-
around time of their measurement crucial. Using a central clinical labora-
tory, it may take up to 15 min from sampling to receiving the analysis results,
which limits the use of these results for clinical decision-making. Point-of-
care testing addresses this issue by decreasing the turnaround time of blood
chemical analysis to a few minutes and is, therefore, an essential component
of the total care of the cardiac patient.

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6.6.1 Anticoagulation and clotting

Measurement of activated clotting time (ACT) remains a standard monitor-
ing procedure to guide heparin-induced anticoagulation for CPB. Many
factors may affect ACT readings in this setting. For example, hemodilution