Effect of systemic lidocaine infusion on optic nerve sheath diameter during laparoscopic hysterectomy: a randomized controlled study.

Background: During laparoscopic hysterectomy (LH), the elevation of intra-abdominal and intra-thoracic pressures due to pneumoperitoneum (PP) results in an increase in intracranial pressure (ICP). The Trendelenburg position (TP) is an accentuating factor. This trial aimed to assess the effect of intravenous (IV) lidocaine infusion on optic nerve sheath diameter (ONSD), a widely accepted surrogate measure for ICP, during PP and TP.

Methods: A randomized, placebo-controlled study was conducted on 66 patients scheduled for LH, equally divided into a lidocaine group and a saline group. ONSD, the primary outcome, was recorded before induction (T1), before PP initiation in the supine position (T2), five minutes (T3), 30 minutes (T4), and 60 minutes (T5) after PP and TP, and five minutes after termination of PP in the supine position (T6). Secondary outcomes included numerical rating scale (NRS) scores at arrival to the post-anesthesia care unit (PACU), 6, 12, and 24 hours after surgery, and postoperative adverse effects.

Results: ONSD at T4 and T5 was significantly lower in the lidocaine group than in the saline group (T4: 4.94±0.43 mm vs. 5.27±0.37 mm; P =0.003, T5: 5.08±0.46 vs. 5.41±0.38 mm; P =0.004). The lidocaine group had significantly lower NRS values than the saline group only at PACU arrival (median [Q1-Q3]: 5 [4-6] vs. 6 [5-6.25]; P =0.016). Fewer patients in the lidocaine group experienced postoperative headache (P =0.029).

Conclusions: IV lidocaine during LH can attenuate the ONSD distension, decrease pain scores at PACU arrival, and reduce the incidence of postoperative headache.