Ultrasonographic optic nerve sheath diameter for predicting elevated intracranial pressure during laparoscopic surgery: a systematic review and meta-analysis.

Abstract

Laparoscopic surgery involves the creation of a carbon dioxide (CO2) pneumoperitoneum to facilitate a clear surgical view, which may result in an elevated intracranial pressure (ICP). Depending on the surgical area, steep Trendelenburg positioning may be used as well, further increasing the ICP. The objective of this study was to assess the effects of laparoscopic surgery on changes in ICP assessed by ultrasonographic measurement of optic nerve sheath diameter (ONSD), which is a generally accepted simple, reliable, and non-invasive ICP measurement technique. A computerized literature search was performed in August 2016 to identity prospective studies that measured ONSD to assess ICP changes during laparoscopic surgery. The primary outcome was the change in ONSD during the early (0-30min) and late (30-120min) periods after initiating pneumoperitoneum, compared with baseline values measured after anesthesia induction. Mean differences (MDs) with 95% confidence intervals [CIs] were calculated. Nine observational studies and one randomized controlled trial, with a total of 460 subjects, were analyzed. Compared to the baseline value after anesthesia induction, significant increases in ONSD were observed in both the early period (MD 0.46, 95% CI 0.31-0.61, P<0.001, I 2=97.3%) and late period (MD 0.67, 95% CI 0.20-1.14, P=0.005, I 2=99.2%). Comparing the ONSD during the early and late periods revealed no significant differences over time. The current meta-analysis revealed that ICP elevation during laparoscopy could be anticipated through a significant increase in the ONSD in the early (0-30min) and late (30-120min) periods during CO2 pneumoperitoneum.