Preemptive sub-Tenon's anesthesia for pars plana vitrectomy under general anesthesia: is it effective?

Adverse Events during Vitrectomy under Adequacy of Anesthesia-An Additional Report

The intraprocedural immobilization of selected subsets of patients undergoing pars plana vitrectomy (PPV) requires the performance of general anesthesia (GA), which entails the intraoperative use of hypnotics and titration of opioids. The Adequacy of Anesthesia (AoA) concept of GA guidance optimizes the intraoperative dosage of hypnotics and opioids. Pre-emptive analgesia (PA) is added to GA to minimize intraoperative opioid (IO) usage. The current additional analysis evaluated the advantages of PA using either COX-3 inhibitors or regional techniques when added to AoA-guided GA on the rate of presence of postoperative nausea and vomiting (PONV), oculo-emetic (OER), and oculo-cardiac reflex (OCR) in patients undergoing PPV. A total of 176 patients undergoing PPV were randomly allocated into 5 groups: (1) Group GA, including patients who received general anesthesia alone; (2) Group T, including patients who received preventive topical analgesia by triple instillation of 2% proparacaine 15 min before induction of GA; (3) Group PBB, including patients who received PBB; (4) Group M, including patients who received PA using a single dose of 1 g of metamizole; (5) Group P, including patients who received PA using a single dose of 1 g of acetaminophen. The incidence rates of PONV, OCR, and OER were studied as a secondary outcome. Despite the group allocation, intraoperative AoA-guided GA resulted in an overall incidence of PONV in 9%, OCR in 12%, and OER in none of the patients. No statistically significant differences were found between groups regarding the incidence of OCR. PA using COX-3 inhibitors, as compared to that of the T group, resulted in less overall PONV (p < 0.05). Conclusions: PA using regional techniques in patients undergoing PPV proved to have no advantage when AoA-guided GA was utilised. We recommend using intraoperative AoA-guided GA to reduce the presence of OCR, and the addition of PA using COX-3 inhibitors to reduce the rate of PONV.

Preventive Analgesia, Hemodynamic Stability, and Pain in Vitreoretinal Surgery

Background and Objectives: Although vitreoretinal surgery (VRS) is most commonly performed under regional anaesthesia (RA), in patients who might be unable to cooperate during prolonged procedures, general anaesthesia (GA) with intraprocedural use of opioid analgesics (OA) might be worth considering. It seems that the surgical pleth index (SPI) can be used to optimise the intraprocedural titration of OA, which improves haemodynamic stability. Preventive analgesia (PA) is combined with GA to minimise intraprocedural OA administration. Materials and Methods: We evaluated the benefit of PA combined with GA using SPI-guided fentanyl (FNT) administration on the incidences of PIPP (postprocedural intolerable pain perception) and haemodynamic instability in patients undergoing VRS (p < 0.05). We randomly assigned 176 patients undergoing VRS to receive GA with SPI-guided FNT administration alone (GA group) or with preventive topical 2% proparacaine (topical anaesthesia (TA) group), a preprocedural peribulbar block (PBB) using 0.5% bupivacaine with 2% lidocaine (PBB group), or a preprocedural intravenous infusion of 1.0 g of metamizole (M group) or 1.0 g of paracetamol (P group). Results: Preventive PBB reduced the intraprocedural FNT requirement without influencing periprocedural outcomes (p < 0.05). Intraprocedural SPI-guided FNT administration during GA resulted in PIPP in 13.5% of patients undergoing VRS and blunted the periprocedural effects of preventive intravenous and regional analgesia with respect to PIPP and haemodynamic instability. Conclusions: SPI-guided FNT administration during GA eliminated the benefits of preventive analgesia in the PBB, TA, M, and P groups following VRS.

Postoperative Analgesic Efficacy of Sub-Tenon's Block with Levobupivacaine in Retinal Surgery under General Anesthesia

Background:

Vitreoretinal surgery is associated with undesirable intraoperative and postoperative complications including pain, postoperative nausea and vomiting, and oculocardiac reflex (OCR). Systemic analgesics have side effects and are contraindicated in some cases. We hypothesized that the preoperative sub-Tenon's injection of levobupivacaine with general anesthesia would decrease postoperative pain and intraocular pressure as well as the incidence of complication.

Methods:

Eighty patients who were presented for vitreoretinal surgery, aged 30–60 years, were enrolled in the study. General anesthesia was administrated to all patients; then, they were randomized into two equal groups (40 each) – Group I: patients received 5 mL placebo solution for sub-Tenon's block and Group II: patients received 4 mL levobupivacaine 0.5% in 1 mL saline for sub-Tenon's block. Postoperative pain was evaluated using a verbal pain scale. Surgeon satisfaction, postoperative analgesic consumption, and perioperative hemodynamics were also reported.

Results:

Verbal rating pain scores were significantly lower at the first 6 h postoperative in Group II (sub-Tenon's levobupivacaine) compared to Group I (sub-Tenon's placebo). First analgesic rescue time and total dose of analgesic consumption were significantly reduced in Group II compared to Group I. There was a lower incidence of OCR with sub-Tenon's levobupivacaine (Group II), also surgeon satisfaction was significantly superior in the same group.

Conclusion:

The combination of general anesthesia with sub-Tenon's block using levobupivacaine in retinal surgery patients reduces pain scores after surgery; total analgesia requirement also decreases the incidence of OCR.