: This study aimed to evaluate safety and efficacy of adding two different doses of neostigmine to the local anesthetic lidocaine in peribulbar block anesthesia for cataract surgery.
This randomized, double blind, parallel group, controlled trial (Trial registration number: IRCT20210106049952N1) included 60 patients (30–70 years-old), ASA physical status I, II, or III who were scheduled for cataract surgery. Patients received standard peribulbar block (Group C) or standard block plus 0.25 mg neostigmine (Group N25) or 0.5 mg neostigmine (Group N50). All patients were assessed for primary outcomes including hemodynamics and onsets of motor and sensory blocks. Secondary outcomes included duration of block, patient’s and surgeon’s satisfaction, postoperative pain, and time to first analgesic dose.
Mean onset of motor block was significantly shorter in N25 and N50 groups (72.25 ± 20.3 and 44.3 ± 10.4 sec, respectively) than in control group (110.25 ± 35.6 sec). Onset of sensory block was significantly shorter in N50 group compared to control group as well as N25 group (P < 0.001). A significantly longer mean duration of block was observed in N50 group (173.55 ± 31.09 min) in comparison to control group (79.75 ± 12.51 min) and N25 group (81.25 ± 6.25 min). Mean time till first analgesic dose showed significant differences between the three groups C, N25, and N50 (2.85 ± 0.47, 3.45 ± 1.28, and 7.1 ± 1.25 h, respectively, P < 0.001). Only two patients belonging to N50 group developed postoperative nausea and vomiting.
Neostigmine in 0.5 mg was superior to 0.25 mg dose when added to the local anesthetic lidocaine in peribulbar anesthesia for cataract surgery regarding both sensory and motor block as well as postoperative analgesia.