Influence of body core temperature on blood loss and transfusion requirements during off-pump coronary artery bypass grafting: A comparison of 3 warming systems

Background: The aim of this prospective randomized trial was to evaluate the efficacy of 3 intraoperative warming systems (Warm-Touch, Thermamed SmartCare OP system, and Allon 2001) on maintenance of normothermia and to investigate their effects on perioperative bleeding and transfusion requirements in patients undergoing off-pump coronary artery bypass grafting. Methods: With institutional approval/patient informed consent, 90 patients presenting for elective multiple off-pump coronary artery bypass grafting were randomly assigned to 1 of the 3 warming systems. Active warming was started after the induction of anesthesia. Perioperative transfusion was based on international guidelines. Body core temperature was recorded every 30 minutes during operation. Perioperative blood loss, autotransfusion, and allogenic transfusions were recorded. Analysis of variance was performed with post hoc Scheffe tests and chi(2) tests. Results: Normothermia could be sufficiently maintained during operation by the Allon 2001 only. Final body core temperature was 34.7 degrees C +/- 0.9 degrees C (Warm-Touch), 35.6 degrees C 0.8 degrees C (Thermamed SmartCare OP), and 36.5 degrees C +/- 0.4 degrees C (Allon 2001; P < .001, Warm-Touch vs Thermamed SmartCare OP. Warm-Touch vs Allon 2001, and Thermamed SmartCare OP vs Allon 2001). Perioperative blood loss was 2683 +/- 1049 mL (Warm-Touch), 2300 +/- 788 mL (Thermamed SmartCare OP), and 1497 +/- 497 mL (Allon 2001; P = .195, Warm-Touch vs Thermamed SmartCare OP; P < .001, Warm-Touch vs Allon 2001; P = .001, Thermamed SmartCare OP vs Allon 2001). Transfusion requirements were 1097 874 mL (Warm-Touch), 986 744 mL (Thermamed SmartCare OP), and 431 +/- 387 mL (Anon 2001; P = .838, Warm-Touch vs Thermamed SmartCare OP; P = .003, Warm-Touch vs Allon 2001; P = .013, Thermamed SmartCare OP vs Allon 2001). Free of allogenic transfusion were 15 (51.7%; Warm-Touch), 18 (60%; Thermamed SmartCare OP), and 24 (82.8%; Allon 2001) patients (P = .037). Conclusions: The goal of normothermia during off-pump coronary artery bypass grafting was best achieved by the Allon system. With this concept, overall blood loss and transfusion requirements were reduced, hence indicating improved quality of perioperative care.