Effect of epidural anesthesia on the optic nerve sheath diameter in patients with pre-eclampsia: a prospective observational study

Abstract

Introduction: Optic nerve sheath diameter (ONSD) reflects intracranial pressure and is increased in pre-eclampsia. Administrating a significant volume of epidural solution into the epidural space can potentially increase ONSD. We investigated the impact of epidural local anesthetic injection on ONSD in patients with pre-eclampsia.

Methods: Patients with pre-eclampsia (n=11) and normotensive pregnant women (n=11) received de novo epidural anesthesia for cesarean delivery. We administered 21 mL of an epidural solution containing 2% lidocaine and 50 μg fentanyl into the lumbar epidural space in incremental doses. ONSD was measured at baseline, 3, 10, and 20 min after completing the epidural injection, after delivery, and at the end of surgery. Primary outcome was the change in ONSD from baseline to 3 min after epidural injection in patients with pre-eclampsia and normotensive pregnant women. Serial changes in the ONSD were analyzed using a linear mixed model.

Results: At baseline and 3 min after epidural drug injection, ONSD was significantly larger in patients with pre-eclampsia than in normotensive mothers (5.7 vs 4.1 mm, p=0.001 and 5.4 vs 4.1 mm, p<0.001, respectively). However, there were no significant changes in ONSD at 3 min after injection from baseline in either group (p>0.999). Linear mixed model demonstrated that ONSD did not change after epidural anesthesia in either group (p=0.279 and p=0.347, respectively).

Conclusions: Despite a higher baseline ONSD in pre-eclampsia, epidural anesthesia did not further increase ONSD. Our findings indicate that epidural anesthesia can be safely administered in patients with pre-eclampsia at risk of increased intracranial pressure, without other intracranial pathology.