*Assistant Professor of Anesthesiology
†Assistant Professor of Laboratory Medicine
‡Special Projects Associate
§Professor of Surgery
Address correspondence and reprint re-
quests to Dr. Ereth at the Department of
Anesthesiology, Mayo Clinic and Mayo Foun-
dation, 200 First St., S.W., Rochester, MN
Supported by the Mayo Foundation for Med-
ical Education and Research, Rochester, MN.
Received for publication March 26, 1998;
revised manuscript accepted for publication
July 17, 1998.
Temperature and Duration of
Mark H. Ereth, MD,* Gregory A. Nuttall, MD,*
William C. Oliver, Jr., MD,* Paula J. Santrach, MD,†
Rahshana D. Price,‡ Hartzell V. Schaff, MD§
Department of Anesthesiology, Mayo Clinic and Mayo Foundation, Rochester, MN
Study Objective: To determine the influence of temperature and duration of cardiopul-
monary bypass (CPB) on blood loss and transfusion requirements.
Design: Retrospective chart review.
Setting: Tertiary care, academic medical institution.
Measurements and Main Results: The charts of 378 patients who had undergone
primary elective coronary artery bypass graft surgery were studied. Systemic perfusion of
CPB had been conducted between 20°C and 37°C in all patients. Patient demographic,
temperature during CPB, duration of CPB, blood loss, and transfusion requirements were
all recorded. Hypothermic CPB patients had minor increases in requirements for transfu-
sion of red blood cells (RBC; p ϭ 0.01), fresh frozen plasma (FFP; p ϭ 0.01), platelets
(PLT; p ϭ 0.003), and total (allogeneic and autologous) blood products (p Ͻ 0.001).
Multivariate analysis revealed that decreased temperature after adjusting for duration was
predictive of allogeneic (RBC, FFP, PLT, and cryoprecipitate) and total (allogeneic and
autologous) transfusion requirements. The duration of CPB correlated with decreased
temperature (r ϭϪ0.455; p Ͻ 0.0001). After adjusting for temperature, duration was
only predictive of total (allogeneic and autologous) transfusion requirements.
Conclusions: The institution of warm CPB has many ramifications for clinical practice.
The hypothermic induced platelet dysfunction and increased duration associated with cold
CPB may contribute to the minor increases in transfusion requirements. However,
temperature appears to be a weak factor, neither supporting nor refuting the use of warm
or cold CPB. © 1998 by Elsevier Science Inc.
Keywords: Blood loss, surgical; cardiac surgery; cardiopulmonary bypass:
duration, temperature; transfusion.
The increasing use of warm (normothermic and mildly hypothermic) cardio-
pulmonary bypass (CPB) in patients undergoing cardiac surgery has initiated
debate of the risks and benefits between normothermic and hypothermic
Although this debate has resulted in a number of clinical studies on
varying outcomes, limited information has been published pertaining to blood loss
Journal of Clinical Anesthesia 10:588–592, 1998
© 1998 Elsevier Science Inc. All rights reserved. 0952-8180/98/$19.00
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