Cardiopulmonary bypass technologies - Biomaterials and Devices for the Circulatory System - page 163

The principles developed for CPB have led to the employment of effec-
tive veno-arterial and veno-venous bypass techniques that have been used
in hepatic transplantation and other procedures involving the abdominal
viscera. 47 Isolated hyperthermic limb perfusion is a new technique that is
available to deliver high dose chemotherapy to a tumor-bearing region of
the body, without subjecting the patient to the systemic toxicity and side-
effects associated with chemotherapy.
A well-trained, experienced and knowledgeable team signifi cantly
decreases morbidity and improves survival in any of these procedures.
These options for CPB have encouraged desperate perfusionists to see their
future.

6.8 Future trends

With respect to the simple rules applied to assessing a potential investment
opportunity, CPB presents a mixed picture. CPB certainly has history; clini-
cal CPB is over 50 years old, a period during which it has grown both in
terms of the number of procedures carried out annually and the technology
employed. Additionally, CPB is the focus of considerable current activity,
in terms of applying both new materials and techniques.
In the greater context of the evolution of CPB, the enormous progress
made and longevity added, we still do not control the heparinised blood-
surface interface. CPB is still not possible without heparin except under
unusual and somewhat dangerous circumstances. Control of the blood-
surface interface without heparin is a goal similar to the goal that open
cardiac surgery was at the dawn of the twentieth century. We aspire to insert
artifi cial devices, pumps, and synthetic organs within the circulation. The
overwhelming problem for a novel anti-infl ammatory technique currently
available is our current inability to carefully measure and account for how
an individual patient will respond to CPB. There is an enormous variability
in this response. Whenever a study demonstrating lack of clinical effect of
a theoretically promising strategy or signifi cant contribution to the clinical
outcome is discussed, we should wonder whether the patient population is
of high or low enough risk (individual biologic variability fully or equally
accounted in the design). Given the deleterious impact of the infl ammatory
response to CPB, the most vulnerable patients are of high risk requiring
complex procedures. A strategy that uses multiple agents to limit activation
would appear to be logical. This kind of broad approach may, however,
impact the coagulation cascade and immune system, and the value of this
anti-infl ammatory strategy must be balanced against the individual patient's
risk.
The infl ammatory response is not intrinsically pathologic and initiates the
healing process. Amelioration of the excessive infl ammatory response must

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