Effect of intraoperative warming on hemostasis in patients undergoing radical operation for esophagus cancer / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of intraoperative hypothermia and warming on hemostasis using thromboelastography(TEG)during radical esophagus cancer operation performed under general anesthesia combined with thoracic epidural block.Methods Sixteen ASA Ⅰ or Ⅱ patients undergoing elective radical esophagus cancer operation were randomly allocated to one of two groups(n=8 each)control group and warming group.The patients were unpremedicated.The operating room temperature was set at 21℃.Epidural catheter was placed at T_(7,8) and advanced 4 cm into epidural space.Correct epidural placement was confirmed by a test dose of 4 ml 1% lidocaine.0.375% bupivacaine was used during operation.General anesthesia was induced with fentanyl,thiopental and succinylcholine and maintained with isoflurane inhalation and intermittent i.v.boluses of vecuronium after endobronchial intubation with double lumen catheter.The patients were mechanically ventilated (V_T=8-10 ml?kg~(-1),RR=10-12 bpm,IE=12,FiO_2=100%).In warming group TC-2000 wanning system (Thermacave,USA)was used.The lower part of the body was warmed for 45 min before induction of anesthesia (temperature was set at 38℃).After induction warming was continued(temperature was set at 43℃).In control group no wanning was provided.The fluid infused during operation was all warmed to 37℃.Tympanic temperature measurement was started from 20 min before induction and recorded every 10 min afterwards.TEG was performed before induction of anesthesia(T_0) and at 150 min after induction(T_1).The blood samples were divided into 2 aliquots of which one was tested at 37℃ and the other at patient's actual core temperature.Results The two groups were comparable with respect to age,sex,body weight duration of operation and the amount of fluid infused during operation.At T_1 the tympanic temperature was 34.7?0.4℃ in control group and 36.5?0.3℃ in warming group.At T_1 in control group the reaction time(R)and clot formation time(K)were significantly prolonged and a angle was significantly reduced when TEG was measured at core temperature compared with those measured at 37℃ (P＜0.05).At T_1 when TEG was measured at core temperature R and K were significantly shorter and a angle was significantly wider in warming group than in control group (P＜0.05).There was no significant difference in MA between the two groups at T_1.Conclusion Mild hypothermia developed during operation can impair bemostasis.Maintenance of normal body temperature(core temperature)during operation is necessary.