CARDIOVASCULAR
ENGINEERING
Journal for Extracorporeal Circulation, Assist Devices,Transplantation and Artificial Organs
|
|
CARDIOVASCULAR
|
Volume 3, 1998, No 1 |
Abstract:
Hypothermic cardiopulmonary bypass (CPB) is a well established
technique used during cardiac surgery during which the patient is
actively cooled to a core temperature of approximately 28°C.
Hypothermia protects from ischaemia by reducing metabolic rate
and therefore oxygen demand, impairing complement activation and
reducing free radical activity. As surgery nears completion, the
patient is actively rewarmed and separation from CPB occurs only
when core temperature reaches 37°C. Despite achieving
normothermia, core temperature usually falls sharply by 2-3°C in
the post-operative period due to transfer of heat from a warm
core to cold periphery. Post-operative hypothermia icreases
morbidity through cardiovascular instability, metabolic acidosis,
impaired coagulation, immunosuppression and prolonged clearance
of anaesthetic drugs. Post-operative hypothermia can be minimised
by ensuring adequate rewarming. Core temperature or
core-peripheral temperature difference on termination of CPB
which are traditional measures of adequate rewarming do not
correlate well with the degree of hypothermia. Other indices of
adequate rewarming have therefore been examined. Measurement of
thermal energy balance, the amount of heat extracted and returned
to the patient during cooling and rewarming on CPB, has been
examined as a measure of adequate rewarming. This more
physiological approach correlates better with the degree of
post-operative hypothermia and may ultimately provide a better
measure of adequate rewarming from hypothermic CPB.
Keywords:
surgery, cardiac, hypothermia, induced, temperature, core
Address for Correspondence:
Reference:
(CVE. 1998; 3 (1): 36-42)
[Pabst Science Publishers] [CVE Homepage] [Contents] [Editorials] [Masthead] [Search] [Orders]
PABST SCIENCE PUBLISHERS
Lengerich, Berlin, Düsseldorf,
Leipzig, Riga, Scottsdale AZ (USA),
Wien, Zagreb