• The purpose of this study is to understand and grasp the incidence rate of hypothermia during perioperative period of elective operations under general anaesthesia in Beijing.
• The purpose of this study is to carry out a subgroup analysis on the survey data and explore the high-risk factors for the incidence of hypothermia.

This survey was anticipated to enroll 800 patients who underwent elective operations with general anaesthesia from 24 hospitals in Peking. After obtaining approval from the Ethical Committee related to research involving human subjects,the investigators will enroll the patients according to the inclusion and exclusion criterion. The tympanic temperature(measured by Braun PRO4000 Thermometer) will be monitored at the following time points respectively: arrived at waiting area, enter the OR room, 5 min before and after anesthesia induction, every 15 min during the operation, operation ended,arrived at PACU. Other information will also be collected, the investigators will record the type and dosage of anesthesia drug,duration of surgery and anesthesia, the patient warming method or if it is used.operation room temperature,the amount of the infusion of intravenous fluids and blood,etc. during the whole operation procedure. The other information will be followed up and recorded after the operation(within 30 days postoperation) which incudes ICU stays, hospital stays, incision infection, new cardiology events.etc.

The contract research organization will be delegated to do the site monitor once a week for each hospital participate the survey during the recruitment and perform the source data validation at the same time to review the related medical records,source data and the case report forms, etc.to ensure the data accuracy and completeness

Data management will be conduct through the whole survey procedure. EPIDATA3.1 software was used for compile the inputting procedure for data inputting and management. In order to guarantee the correctness of the data, two data managing staffs should input and verify the data independently.

SAS9.2 statistical analysis software was used for the calculation of all the statistical analyses. The number of cases, mean, standard deviation, median value, maximal value and minimal value should be calculated for the descriptions of the qualitative parameters. Number of cases and percentages are used for the descriptions on the classification parameters.Two side test is used for all the statistical tests, P<0.05 indicates that the difference is statistically significant (unless indicated otherwise), and 95% confidence is used as the confidence interval.

Inclusion Criteria:

• Male or female, no limitation on age
• Subject who will undergo elective surgery with general anaesthesia
• The duration of surgery is expected to be over 40 minutes
• The subject agreed to participate in the study and signed the informed

Exclusion Criteria:

• Central high fever caused by enter nerves system disease or condition, including that induced by cerebrovascular disease, cerebral trauma, cerebral surgeries, epilepsy and acute hydrocephalus
• Thermoregulation abnormalities including malignant hyperthermia (MHS) and neuroleptic malignant syndrome, hypothyroidism or hyperthyroidism diagnosed by substantial evidence
• Infectious fever
• Patients whose core temperature is higher than 38.5°C within 7 days before surgery
• Diseases or that may lead to inaccuracy in measurement, such as ear infection
• Surgeries with active cooling process during operation

Patients who undergo elective surgery with general anaesthesia

39 patients were eliminated for the reasons operation cancelled temporarily or volate the eligible criteria, so 830 participants for analysis was determined in the end.

In this study some information can hardly be completely collected such as wound infection incidence within 30 days postoperation, so further intervention study is needed to explore the relationship between hyperthermia and the potential complication.