Effect of volume used in sub-Tenon's anaesthesia on efficacy and intraocular pressure: a randomized clinical trial of 3 mL versus 5 mL

Authors: Niall Patton; Tahira Y Malik; Tariq M Aslam; James H Vallance

Source: Clinical & Experimental Ophthalmology, Volume 32, Number 5, October 2004 , pp. 488-491(4)

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Abstract:

Purpose: To compare the effect of volume used in sub-Tenon's anaesthesia on efficacy and intraocular pressure (IOP).

Methods: A prospective, randomised clinical trial was conducted on 52 eyes of 52 consecutive patients undergoing sub-Tenon's anaesthetic for cataract surgery. Eyes were randomly assigned to either 3 mL or 5 mL volume of anaesthetic solution (0.5% bupivacaine/2% lidocaine in a 50:50 mixture). The main outcome measures were akinesia 5 min post-administration of anaesthetic, changes in IOP immediately after and 5 min after anaesthetic administration, and patient pain perception during procedure.

Results: The level of kinesia was greater in the 3 mL group (n = 25) compared to the 5 mL group (n = 27) (P = 0.001, Mann–;Whitney U-test). There was no significant difference in pain perception between the two groups (P = 0.464, student t-test). Although there was great variation in IOP changes following sub-Tenon's anaesthetic, there was a trend for a larger rise in mean IOP immediately after anaesthetic administration in the 5 mL group (mean ± SD +5.6 ± 4.2 mmHg) compared to the 3 mL group (+4.3 ± 3.8 mmHg), but this did not reach statistical significance (P = 0.25, student t-test).

Conclusions: A 5 mL volume of anaesthetic provides akinesia superior to a 3 mL volume in sub-Tenon's anaesthesia for cataract surgery.

Keywords: efficacy; intraocular pressure; ocular anaesthesia; sub-Tenon's injection

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1442-9071.2004.00865.x

Publication date: 2004-10-01