Year : 2012  |  Volume : 15  |  Issue : 4  |  Page : 273-

Invited Commentary

Deepak K Tempe 
 Department of Anaesthesiology and Intensive Care, G.B. Pant Hospital, New Delhi, India

Correspondence Address:
Deepak K Tempe
Director-Professor and Head, Department of Anaesthesiology and Intensive Care, G.B. Pant Hospital, New Delhi - 110002

How to cite this article:
Tempe DK. Invited Commentary.Ann Card Anaesth 2012;15:273-273

How to cite this URL:
Tempe DK. Invited Commentary. Ann Card Anaesth [serial online] 2012 [cited 2022 Jun 29 ];15:273-273
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Full Text

Deep hypothermic circulatory arrest is widely utilized as the major cerebral protection strategy during circulatory arrest periods during cardiac surgery, particularly during surgical repair of thoracic aorta. It is known to cause coagulation derangements, increased postoperative bleeding, and red blood cell (RBC) and blood product transfusion requirements. Mazzeffi and colleagues [1] propose a different concept of "deep hypothermia proportion" as a predictor of bleeding and transfusion requirements. The deep hypothermia proportion was calculated by dividing the total deep hypothermia time (<20°C, with or without circulatory arrest) by the total cardiopulmonary bypass (CPB) time. In a retrospective analysis of 507 patients undergoing thoracic aortic surgery, they report that the RBC transfusion was associated with deep hypothermia proportion, but transfusion of platelet and fresh frozen plasma (FFP) were not. Furthermore, the positive relationship of deep hypothermia proportion to perioperative RBC transfusion existed only if the CPB time was between 120 to 180 minutes.

The major limitation of the study is the fact that RBC transfusion was used as a proxy to estimate the degree of perioperative bleeding and coagulopathy. This may have been acceptable, if the cardiac unit had followed a uniform transfusion trigger and shown that the hemoglobin/hematocrit levels at various stages for patients who received higher transfusion vs lower transfusion were comparable. In the present study, the individual surgeons and anesthetists made decisions regarding transfusion. In these circumstances, the reliability and reproducibility of these results is really questionable. Furthermore, no explanation has been offered for why the deep hypothermia proportion had no relation to platelet and FFP transfusion, and was relevant only if the CPB times were shorter (120-180 minutes). In essence, the heterogeneity in transfusion practice is the major drawback of the study, which may also account for absence of any relationship between transfusion requirement and clopidogrel, aspirin, aprotinin, and epsilon aminocaproic acid use. The relationship of deep hypothermia proportion to bleeding and transfusion needs to be studied further before any definite conclusions can be drawn.


1Mazzeffi M, Marotta M, Lin Hung-Mo, Fischer G. Duration of deep hypothermia during aortic surgery and the risk of perioperative blood transfusion. Ann Card Anaesth 2012:15:266-73.