Comparative evaluation of optic nerve sheath diameter in patients undergoing laparoscopic cholecystectomy using low and standard pressures of gas insufflations.

ABSTRACT

Background and Aims: Intra-abdominal insufflation of CO2 is associated with an increase of intracranial pressure (ICP). We conducted this randomized control trial to compare the impact of low vs standard pressure pneumoperitoneum on ICP through the ultrasonographic estimation of the optic nerve sheath diameter (ONSD). Material and Methods: Patients of age group 18-80 years planned for laparoscopic cholecystectomy were randomly allocated into two groups; group S (standard pressure of 12-16 mmHg) and group L (low pressure of 8-10 mmHg) on the basis of intra-abdominal pressures used for the surgery. All were administered general anesthesia and end-tidal carbon dioxide (ETCO2) was maintained between 35 and 40 mmHg and peak airway pressures less than 35 cmH2O. ONSD was measured in either eye at a point 3 mm posterior to the globe at following time intervals; baseline, 5 min after induction, 10 min after insufflation, 10 min after reverse Trendelenburg, intraoperatively during surgery and after exsufflation in the supine position. Results: The demographic profile and operative times were comparable. ONSD was measured in 100 patients in each group for both the eyes and no patient had values above the cutoff value of 5.0 mm. No significant difference in the ONSD was observed at the above mentioned time intervals between the groups. There was a statistically significant lower value of the heart rate and mean arterial pressure in the low-pressure group. Conclusion: Intra-abdominal insufflation of CO2 at standard and low pressures does not increase ICP in short duration surgeries and thus both the pressures can be safely used in adult patients operated in reverse Trendelenburg position. Advantages of low pressure were limited to better hemodynamic control.