| Perioperative inadvertent hypothermia (core temperature below 36℃) is a common perioperative complication of surgery, and the incidence of perioperative hypothermia ranges from 50% to 90%. Even mild peri-operative hypothermia can cause a variety of adverse effects, such as: morbid myocardial events, increased risk of surgical peri-prosthetic infections, increased duration of hospitalization, intra-operative blood loss and prolonged postanesthetic recovery. Thoracic surgery is known to be associated with long surgery, lateral position, and large surgical fields, which appear to impair body temperature management. To determine the incidence of intraoperative hypothermia and its associated risk factors, to evaluate the effect of mild perioperative hypothermia on the coagulation-fibrinolysis system in thoracic surgery patients, a randomized controlled study investigating effectiveness of active cutaneous warming system on blood coagulation was conducted. Thromboelastography (TEG) allows for a comprehensive assessment of coagulation that can be regulated for temperature. TEG was evaluated in thoracic surgery patients undergoing perioperative hypothermia. A total of 120 patients who had undergone elective thoracic surgery were enrolled. Core temperature was determined at tympanic membrane and an nasopharyngeal temperature probes. All patients undergoing thoracic surgery were covered with standard sterile drapes. The risk factors associated with perioperative hypothermia were evaluated univariately and multivariately using logistic regression analysis. Since the potential confounders could include age, BMI, ASA physical status, baseline core temperature prior to anesthesia, type of anesthesia, amount of intravenous fluid replacement, duration of anesthesia and surgery etc. And then 64 patients undergone thoracic surgery were randomized into the passive cutaneous warming system (control) group and active cutaneous warming system (intervention) group. Patients in the control group were intraoperatively warmed with a quilt, while patients in the intervention group were preoperatively and intraoperatively warmed with a forced air warming blanket. Core temperature was recorded at 5 minutes before induction of anesthesia (TO),5 minutes after induction of anesthesia (T1),15min,30min,45min,60min and until the end of surgery. Blood specimens were collected for standard coagulation tests and TEG tests at 5minutes before induction of anesthesia, intraoperative and the end of surgery. Postoperative shivering and waking time after anesthesia were also recorded. Statistical analysis was performed with SPSS 19.0 software. Overall incidence of intraoperative hypothermia was 78.3% in all surgical patients. Multivariate logistic regression analysis revealed that the incidence of hypothermia was closely associated with intravenous fluid (IVF) replacement>2000 ml (OR=3.499, P<0.05) in comparison with IVF less than 2000ml. In contrast, protective factors for hypothermia were patient baseline temperature prior to anesthesia (OR=0.074, P<0.05). Core temperature in control group was significantly decreased since 30 min after the induction of anesthesia until the end of surgery comparing to that at the intervention group. No differences in TEG variables were observed between the two groups at before induction of anesthesia. At the end of surgery, control group patients showed significantly difference compared with intervention group in TEG parameters (ACT, K, a, MA) (P<0.05), except for LY30 (P>0.05). Moreover, it was also observed that with anesthesia and operation time increased, ACT and K were prolonged in control group, MA and a were shortened in control group, comparing with intervention group. ACT and K were prolonged, MA and a were shortened in temperature adjusted samples, comparing with non-adjusted samples. There was no significant change in PT, APTT, INR, RBC, HB, PLT comparing with intervention group, except for FBG. Compared with the intervention group, control group in the incidence of postoperative shivering was definitely too high and waking time significantly prolonged (P<0.05). Mild hypothermia in patients undergoing thoracic surgery is common. Mild hypothermia can affect the coagulation function, such as inhibiting the activity of coagulation factors and fibrinogen, reducing platelet function. This further supported that using active cutaneous warming system can effectively reverse hypothermia induced intraoperative coagulation dysfunction, reduce the incidence of postoperative shivering and shorten waking time after anesthesia. |
PDF Full Text Request