INTRODUCTION

The combination of general and local anesthesia is optimal to provide long-term vitreoretinal interventions more than 90 minutes. Now there are no recommendations which method of local anesthesia is preferred. The Sub-Tenon block may be one of the selection techniques. A long-acting drug such as levobupivacaine or a prolonged lidocaine infusion can be Sub-Tenon administered.

OBJECTIVES

Of this study was to compare the effectiveness of two methods of Sub-Tenon block: prolonged infusion — 1% lidocaine, and injectable — 0.5% levobupivacaine with a general sevoflurane anesthesia.

MATERIAL AND METHODS

The study included of 24 patients who performed vitrectomy under general sevoflurane anesthesia 90—210 minutes duration. After induction a Sub-Tenon block was performed: group 1 — prolonged cateter-block with 1% lidocaine; group 2 — injection of 0.5% levobupivacaine. We evaluated: the activity of oculo-visceral reflexes by heart rate and mean blood pressure, the need for myorelaxants. The level of pain was measured after the surgery on the digital rating scale (NRS). For statistical analysis, the Tukey and Mann—Whitney criteria with the Bonferroni correction were used, α=0.05.

RESULTS

The mean duration of the operation was: in the group 1 — 159.2±11.3 min, in the group 2 — 132.9 ± 10.1 min. The oculocardiac reflex activity showed statistically significant differences into the 2 group, but not between groups. Significant differences of mean arterial pressure was found in group 2 (p=0.006—0.009) and between groups. The average dose of rocuronium in group 1 was 14.6±5.7 mg, in group 2 was 20.8±8.0 mg. In group 1 postoperative pain was significantly less: NRS level — 0.08 points, in group 2: NRS level — 0.75 points.

CONCLUSION

Prolonged Sub-Tenon block with 1% lidocaine for long-term vitreoretinal surgery is more effective and safer technique which provide excellent anesthesia.