Abstract:

Objective To observe the effect of different ventilation modes on the diameter of optic nerve sheath in elderly patients undergoing laparoscopic colorectal cancer surgery. Methods Sixty patients who underwent laparoscopic resection of rectal and sigmoid tumors were selected，including 31 males and 29 females whowere from 60 to 80 years old with ASA Ⅱ grade and BMI 18.5 ~ 28 kg/m2 . They were randomly divided into Group V or Grand P by random number table method. Group V used VCV ventilation mode，and Group P used PCV ventilation mode. Recorded the cross⁃sectional and sagittal average ONSD values of left and right eyes before induction of anesthesia（T0），10 minutes after induction of anesthesia in the supine position（T1）10 minutes（T2）and 60 minutes （T3）after the CO2 pneumoperitoneum Trendelenburg position established，and 10 minutes after the pneumoperito⁃ neum disappeared and supine position resumed（T4）；recorded the peak airway pressure（Ppeak），mean airway pressure（Pmean），PaCO2，PETCO2 at T1⁃T4 ，and HR，MAP，CVP，SpO2 at T0⁃T4；recorded the incidence of nausea and vomiting，dizziness，headache and pulmonary complications during the 3 days after surgery. Results Compared with T1，the ONSD of the two groups increased significantly at T2⁃T4（P < 0.05），compared with T3，the ONSD of the two groups was significantly reduced at T4（P < 0.05），and the ONSD of the P group was more signifi⁃ cant than that of the V group at T2⁃T3 Decrease（P < 0.05）. At T2⁃T3，Ppeak，PaCO2 and CVP in group P were sig⁃ nificantly lower than those in group V（P < 0.05）. There were no significant differences in postoperative complica⁃ tions such as nausea，vomiting，dizziness，and headache between the two groups. Conclusion Compared with volume controlled ventilation，pressure controlled ventilation can effectively alleviate the increase in intracranial pressure during pneumoperitoneum and Trendelenburg position during laparoscopic colorectal cancer surgery.

Key words:

ventilation modes, optic nerve sheath diameter, intracranial pressure, CO2 pneumoperi? toneum, trendelenburg position