Comparison of peribulbar block and general anaesthesia in mechanical vitrectomy: a prospective observational study

Vitrectomy surgery is a common procedure for the treatment of several types of ophthalmologic conditions. It can be performed under regional anaesthesia with peribulbar block (PB) or general anaesthesia (GA). There are no evidence-based recommendations on the optimal anaesthesia strategy for this procedure. The aim of this study was to compare the advantages of PB and GA for vitrectomy surgery.

A prospective observational study was conducted on adults submitted for mechanical vitrectomy between January 2017 and December 2017. Demographic and perioperative data were collected, namely ASA physical status, median arterial pressure, heart rate, postoperative opioid consumption, postoperative nausea and vomiting, times of induction, surgery, recovery, and hospital stay and costs considering medication and material needed. Statistical analysis was performed using SPSS v.25, with chi-square, Fisher and Mann-Whitney U tests, according to the type of variables analysed.

We included 179 patients submitted for mechanical vitrectomy: 91 (51%) with PB and 88 (49%) under GA. Patients submitted to PB were older (69.0 vs. 64.5 years, p=.006) and presented with higher ASA physical status (p=.001). For haemodynamic outcomes, patients submitted to PB presented with less variation of median arterial pressure (-3.0 vs. -13.5mmHg, p=.000) and with no significant differences in heart rate (-2.0 vs. -3.0 bpm, p=.825). In the postoperative period, the PB group presented with decreased need of postoperative analgesia (0.0 vs. 5.0, p=.026) and a lower incidence of nausea and vomiting (1.0 vs. 12.0, p=.001). Times related to anaesthesia and surgery were better in PB group, with shorter induction time (10.0 vs. 11.0min, p=.000), surgery time (56.5 vs. 62.0min, p=.001), recovery time (10.0 vs. 75.5min, p=.000), and hospital stay (2.0 vs. 3.0 days, p=.000). When analysing costs, PB was less expensive than GA (4.65 vs. 12.09 euros, p=.021) CONCLUSION: PB is a reliable and safe alternative to GA for patients undergoing mechanical vitrectomy, permitting good anaesthesia and akinesia conditions during surgery, better haemodynamic stability, and less postoperative complications, especially in older patients and those with more comorbidities.