Perioperative Maintenance Of Normothermia Reduces The Incidence Of Myocardial Ischemia In Elderly Patients With Cardiovascular Disease Undergoing Noncardiac Surgery

Objective: To assess the relationship between body temperature and cardiac ischemia during the perioperative period in Patients with intermediate risk factors of cardiovascular disease undergoing noncardiac Surgery. Method': sixty patients , who were at a intermediate risk or at or more than two lower risk for postoperative cardiovascular events according to "ACC/AHA Guideline for Postoperative Cardiovascular Evaluation for Noncardiac surgery " ,were classify into two groups at random : routine thermal care (hypothermic group, n=30) and additional supplemental warming care (normothermic group, n=30). routine thermal care was delivered according to following protocol. The thermostat in the operating room was set to approximately 21℃. intravenous fluids and blood were not warmed. A heat-moisture exchanger was used in the respiratory circuit for patients receiving general anesthesia. Intraoperatively, the patient was covered above and below the field with 1 layer of paper surgical drapes. Postoperatively, either 1 or 2 warmed cotton blankets were placed over the patient, at the nurse' discretion. Patients in the normothermia group were treated as follows. As in the hypothermic group, the thermostat set to approximately 21℃, intravenous fluids and blood were warmed. A heat-moisture exchanger was used in the respiratory circuit. Depending on the surgical site, an upper- or a lower-body forced-air warming cover was place over the patients . During the Intraoperative both the temperature and airflow setting were adjusted to maintain core temperature at or near37°C. Postoperatively, just like the hypothermic group, either 1 or 2 warmed cotton blankets were placed over the patient, at the nurse' discretion. Used Holter to monitor myocardial ischemias and arrhymias of all patients for 24 hours before operation and for 48 hours postoperative. Postoperative patients were followed in hospital. The material of Holter were assessed in a double-blind fashion. Cardiovascular events were defined , as death cardiac cause ; myocardial infarction; unstable angina/myocardia damage ;congestive cardiac failure ;cerebrovascular accident ;ventricular tachycardia ;arrhythmia with hyper - or hypotension , and compared the different of temperature^ myocardia ischemia and cardiovascular enents between the two groups. Result: There were no significant differences between normothermic group and hypothermic group for mean core temperature before the operation, postoperatively, mean core temperature .was 1..4 °C lower than in the normothermic group on admission to the ICU after surgery (p<0. 05) and remained lower during the early postoperativft period(90 min). Perioperative myocardial ischemia occurred less frequently in the normothermic group(5patients, 17%) than in the hypothermic group(12 patients 40%).Otherwise, there is no statistically significant different on postoperative morbid of cardiovascular events between two groups. Conclusion: In patients with cardiac risk factors who are undergoing noncardiac surgery, perioperative maintenance of normothermia is associated with a reduced incidence myocardial ischemia and postoperative shivering, perioperative maintenance normothermia also reduce the morbid of cardiovascular events but no statistically significant different, if we want to get further conclusion .more sample is needed.