Optic nerve sheath diameter (ONSD) measurement with ultrasound has emerged as a simple, non-invasive and reliable surrogate of invasive intracranial pressure (ICP) measurement. Increase in ICP might lead to postoperative nausea and vomiting (PONV) and postoperative headache. Here, we aimed to evaluate the extent of change in ONSD, resulting from pneumoperitoneum (PP) and Trendelenburg (TP) position during the laparoscopic hysterectomy (LH), by using ultrasonographic ONSD measurement. We also aimed to investigate the relation of ONSD with PONV and postoperative headache.Sixty-one patients undergoing LH with general anesthesia were enrolled in this prospective study. ONSD was measured at 6 time-points during the LH. The primary outcome of the study was the change in ONSD with the introduction of PP and TP. The relation of ONSD with PONV and postoperative headache were the secondary outcomes.ONSD demonstrated an increasing trend from baseline to the 10th minute of the TP. A relative decrease occurred in ONSD following supine positioning which further decreased after the release of the PP. However, even after the release of the PP, the median ONSD was significantly higher compared to the baseline values (5.1 mm vs. 4.9 mm, P < 0.01). Presence of PONV and headache were significantly correlated with the extent of the increase in ONSD from baseline to PP and from baseline to TP. ROC curve analysis revealed that a cut-off value of 5.85 mm for ONSD was predictive for PONV (P < 0.001).Combination of PP and TP leads to a significant increase in ONSD during LH. The extent of the increase in ONSD during the procedure is significantly correlated with PONV and headache occurring within the first three hours of recovery.
