The investigators try to conduct a study to assess the impact of changing patients' lateral decubitus position on BIS readings during esophageal cancer operation. Also, the investigators evaluate the effects of one-lung ventilation and total lung ventilation on BIS value with inhalation agent.
Bispectral index (BIS) was developed to monitor a patient's level of consciousness under general anesthesia. Several factors have been found to alter BIS readings without affecting the depth of anesthesia.Changing a patient's position (head up and head down) significantly affects the BIS values, which might affect the interpretation of anesthetic depth. During esophageal cancer surgery, there were several factors which could affect to BIS values.First, the surgical positions are consisted with supine and lateral decubitus position more than 1 h. Thus, the investigators compare the BIS value of both side on supine and lateral decubitus position by both side approach. Second, the one lung ventilation was applied for surgical filed. It alters the oxygenation and the cerebral flow. Because of these effects, the BIS monitoring can differ by the period of surgery. Thus, in this study, the BIS value of both side monitor throughout the surgery.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
44
All patients applied BIS on both side (Left and Right)
Samsung medical center
Seoul, South Korea
Change in Bispectral index score
The difference of both side BIS value on lateral decubitus position
Time frame: after lateral decubitus position 5 mins, 10 mins, 20 mins, 30 mins
the asymmetry of BIS
The difference of BIS on supine position
Time frame: after supine position 5 mins, 10 mins, 20 mins, 30 mins
oxygenation and BIS
the effects of arterial blood gas analysis (O2 mmH2O and CO2 mmH2O) on BIS
Time frame: intraoperative
The changes of BIS
the difference of BIS divided to 3 BIS level ( \<40,40-60,\>60)
Time frame: intraoperative
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