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Effects of temperature on partial thromboplastin time in heparinized plasma in vitro

Published online by Cambridge University Press:  16 August 2006

M. Felfernig
Affiliation:
Department of Anaesthesiology and General Intensive Care B and Ludwig Boltzmann Institute of Clinical Anaesthesiology and Intensive Care, University of Vienna, Austria
A. Blaicher
Affiliation:
Department of General Anaesthesiology and Intensive Care A and Ludwig Boltzmann Institute of Clinical Anaesthesiology and Intensive Care, University of Vienna, Austria
S. C. Kettner
Affiliation:
Department of General Anaesthesiology and Intensive Care A and Ludwig Boltzmann Institute of Clinical Anaesthesiology and Intensive Care, University of Vienna, Austria
D. Felfernig
Affiliation:
Department of General Anaesthesiology and Intensive Care A and Ludwig Boltzmann Institute of Clinical Anaesthesiology and Intensive Care, University of Vienna, Austria
S. Acimovic
Affiliation:
Department of Anaesthesiology and General Intensive Care B and Ludwig Boltzmann Institute of Clinical Anaesthesiology and Intensive Care, University of Vienna, Austria
S. A. Kozek-Langenecker
Affiliation:
Department of Anaesthesiology and General Intensive Care B and Ludwig Boltzmann Institute of Clinical Anaesthesiology and Intensive Care, University of Vienna, Austria
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Abstract

Background and objective Perioperative hypothermia has been found to impair the coagulation cascade and to increase blood loss and transfusion requirements. The effect of concomitant in vitro heparinization on coagulation during hypo- and hyperthermic conditions has not been well defined.

Methods In the present study, activated partial thromboplastin time was examined in vitro at 33°C, 35°C, 37°C, 39°C and 41°C in normal human plasma in response to unfractionated heparin.

Results Hypothermia ≤ 35°C prolonged activated partial thromboplastin time by 10% compared with test temperatures at 37°C (P < 0.05). Hyperthermia alone had no effect. Unfractionated heparin (0.1–0.4 IU mL−1) increased activated partial thromboplastin time in a dose-dependent manner (by 189% at 0.4 IU mL−1, P < 0.05). Test temperatures of 33°C and 41°C increased heparin-induced prolongation of activated partial thromboplastin time. At a heparin concentration of 0.4 IU mL−1, hypothermia (33°C) and hyperthermia (41°C) prolonged partial thromboplastin time by 12% and 22%, respectively, compared with normothermic test temperature of 37°C within the heparin group (P < 0.05).

Conclusions These observations suggest that both hypo- and hyperthermia increase the response to heparin in vitro. Further studies are needed to identify the effect of patient’s body temperature on heparin activity and bleeding tendency in vivo.

Type
Original Article
Copyright
2001 European Society of Anaesthesiology

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