Temperature control in the operating room is an effective means of controlling bacterial concentration; it is part of the comprehensive control measures, and is both Controlling the reproduction of bacteria in the air also controls the bacteria discharged by patients and medical staff through perspiration; its significance is by no means merely for the comfort of the personnel inside. It is evident that the temperature inside the operating room plays a role in controlling bacterial reproduction.

As for temperature and humidity, when there are no specific requirements, in winter the value may be taken as no lower than the lower limit in Table 4.1, and in summer as no higher than the upper limit in Table 4.1; the temperature and humidity of rooms directly connected to the operating room shall be the same as those of the operating room.

[Reference] According to the Applications volume of the 1999 edition of the U.S. ASHRAE Handbook, the clean air-conditioning system shall be capable of ensuring that the temperature inside the operating room can be adjusted within the range of 17～24℃, whereas the 1991 edition specified 20～24℃, indicating that the adjustable range of room temperature has been expanded. The U.S. "Public Health Service" stipulates 22～24℃; Professor Inoue Uichi of Japan recommends 22～24℃; the United Kingdom specifies 20～21℃; France specifies 20℃; Northeastern Europe 20～22℃; and Central Europe 22～25℃. According to A. Field of the United States, unless the operation is very short, hypothermic functional disorders can occur in almost all patients when the room temperature is ＜21.1℃; when the operation lasts more than 1h and the room temperature is within the range of 21～24℃, 1/3 of patients will develop hypothermic disorders. Of course, to control perspiration, the room temperature should not be too high either. However, surveys of doctors in some domestic hospitals generally indicated that around 25℃ in summer is acceptable, and in winter, in order to reduce heat loss from the exposed parts of the patient's body, the temperature should not be lower than 21℃ at the minimum. Therefore, the "Code" sets the operating room temperature at 22～25℃, while for auxiliary rooms where people stay only briefly or may wear more clothing, the upper and lower temperature limits are relaxed to 21～27℃.

Some foreign standards hold that certain operations require a low-temperature environment, and that the required conditions must even be achieved within half an hour before the start of the operation. Obviously, this cannot be satisfied and guaranteed by ordinary air-conditioning systems, so dedicated air-conditioning units for the operating room must be adopted. Such special requirements should be put forward by the hospital, and this "Guide" will not analyze them further.