Effects of Subtenon Anesthesia Combined With General Anesthesia on Perioperative Analgesic Requirements in Pediatric Strabismus Surgery

The role of surgical factors eliciting oculocardiac reflex of patients undergoing orbital tumor surgery: a retrospective study

PURPOSE

Orbital tumors are an interdisciplinary disease, and surgery is one of the main treatment methods. The oculocardiac reflex (OCR) is a condition of surgery for orbital tumors. The aim of this study was to investigate whether there is an association between many surgical factors and the incidence of OCR in orbital tumor surgery.

METHODS

Comparisons were made between patients with and without OCR using the Mann-Whitney test, Fisher's exact test, and Chi-square test. When comparing multiple groups (groups > 2), to explain which two groups had differences, post hoc testing was used for analysis, and the differences between groups were judged according to the adjusted standardized residuals.

RESULTS

The results showed that the incidence of intraoperative OCR was different based on the different exposed operative field locations (p = 0.021). The OCR incidence in those with lesions involving the orbital apex and lesions adhering to extraocular muscles was higher than that of others (p < 0.001 and p = 0.003). In addition, multivariate logistic regression analysis revealed that orbital apex involvement and extraocular muscle adhesion were highly associated with a higher incidence of OCR (p < 0.001 and p = 0.013), while the operative field located in the lateral-superior orbit was highly associated with a lower incidence of OCR (p = 0.029).

CONCLUSION

In orbital tumor surgery under general anesthesia, lesions involving the orbital apex and lesion adhesion to the extraocular muscles were independent risk factors for OCR, and an operative field located in the lateral-superior orbit was a protective factor for OCR.

Influence of Pre- and Intraoperative Local Anaesthetic in Strabismus Surgery under General Anaesthesia in Adults

BACKGROUND

As studies have shown a reduction in the occurrence of the oculocardiac reflex with the addition of local anaesthesia, we changed our care regime accordingly a few years ago. To promote and establish better patient care, we retrospectively analysed the files of our patients who underwent strabismus surgery from 2013 to 2021 in order to compare strabismus surgery under general anaesthesia with and without local anaesthetics in a routine clinical setting.

PATIENTS AND METHODS

Data from 238 adult patients who had undergone strabismus surgery could be extracted from the files: G1: n = 102, only general anaesthesia; G2: n = 136, preoperative application of tetracaine eye drops and intraoperative subtenon lidocaine/levobupivacaine in addition to general anaesthesia. We compared the two groups in regard to the frequency of oculocardiac reflex, the amount of atropine needed to treat, as well as the amount of antiemetic and analgesic medication given, and time spent in the recovery room.

RESULTS

Mean age of G1 was 50 years and 52 years in G2. There was no significant difference between the kind of surgeries (recessions/resections), the number of patients who had undergone a reoperation, or the duration of the operations. Adding local anaesthetics resulted in significantly less occurrence of oculocardiac reflex (p = 0.009), a reduction in the need for atropine, analgesic, or antiemetic medication, as well as reduced time in the recovery room.

CONCLUSION

As this increases patient safety and comfort and is cost-effective (less time in the recovery room), we recommend adding perioperative local anaesthesia to strabismus surgery performed under general anaesthesia.

Sub-Tenon's bupivacaine injection is superior to placebo for pediatric strabismus surgery: A meta-analysis

BACKGROUND

The effect of post-operation sub-Tenon's bupivacaine injection for pediatric strabismus surgery is controversial. The objective of this meta-analysis is to compare the outcome of sub-Tenon injection of bupivacaine and placebo duringstrabismus surgery.

METHODS

We searched the databases (Pubmed, Cochrane library and EMBASE) and reference lists systematically. Randomized controlled trials (RCTs) comparing sub-Tenon's bupivacaine and placebo injection for pediatric strabismus surgery were included. The methodological quality was evaluated by the Cochrane risk of bias (ROB) tool. Outcome measurements were pain score, oculocardiac reflex (OCR), additional drug consumption and related complications. RevMan 5.4 was used for the statistical analysis and graph preparation. For the outcomes that are not suitable for statistical analysis, descriptive analysis was performed.

RESULTS

A total of 5 RCTs with 217 patients were finally identified and analyzed. Sub-Tenon's bupivacaine injection showed pain relief within 30 min after operation. But with the extension of time, the analgesic effect gradually disappeared at 1 h. It can reduce the incidence of OCR, vomiting and supplementary drug requirements. However, in terms of nausea, there is no difference between the two groups.

CONCLUSION

Sub-Tenon's bupivacaine injection can relieve short-term postoperative pain, reduce the incidence of OCR and vomiting, and reduce the use of supplementary drugs in strabismus surgery.

The Oculocardiac Reflex: A Review

BACKGROUND

A typical oculocardiac reflex (OCR) is a moderate trigemino-vagal bradycardia elicited by tension on an extraocular muscle (EOM) during strabismus surgery; however, many other orbital stimuli can elicit cardiac slowing including retinopathy of prematurity examination.

METHODS

World literature related to trigeminovagal and oculocardiac reflex covering over 15,000 patients including 51 randomized clinical trials and case reports are analyzed and reviewed. Under an ongoing observational trial in Alaska, anesthetic, patient and surgical influences on routine strabismus surgery using prospective, uniform EOM tension are compared seeking sufficient sample size to characterize this individually widely variable cardiac response.

RESULTS

With adequate sample size, and emphasizing clinical studies controlling type of EOM, muscle tension amount and duration, anticholinergic and opioid medications, the following augment OCR; rapid-acting opioids and dexmedetomidine while OCR is reduced in older patients, the right eye, less EOM tension, deeper inhaled agents, hypocarbia, anticholinergic medications and orbital block. In re-operations, the former are relatively poor predictors of subsequent OCR.

CONCLUSION

Profound bradycardia can occur in almost 10% of strabismus surgery cases without anticholinergic preventive measures, but reliable prediction of OCR remains elusive. With foreknowledge and careful anesthetic monitoring of the patient before EOM manipulation, residual adverse sequelae from OCR are fortunately very rare. Despite well over a century of experience, the teleology for this occasionally dramatic cardiac response to eye surgery is still not known.

The Impact of Re-Operation, Relatives and Race on the Oculocardiac Reflex During Strabismus Surgery

Purpose

The oculocardiac reflex (OCR) is a trigeminovagal bradycardia elicited by tension on an extraocular muscle (EOM). Using three decades of observational data, we investigated whether or not individual strabismus patients are prone to oculocardiac reflex.

Patients and Methods

All patients undergoing strabismus surgery from 1992 to 2019 had deliberate 10-second, 200-gram square-wave tension on extraocular rectus muscles with anesthetic variables recorded. OCR was defined as the maximally tension-altered heart rate as a percent of stable baseline heart rate.

Results

OCR was compared in 2532 original cases with 323 re-operations. The 169 cases that used anticholinergics (99% OCR) were excluded from the analysis. The median OCR, a 15% drop, was found to be 85% (95% CI 39%, 102%,; range 5–151%). Factors that showed a significant effect on the OCR were the type of EOM with lateral rectus least (Kruskal–Wallis X²(3)=8, p<0.05), and adults had less OCR compared to the children (X²(2)=105, p<0.01). Factors that showed an augmenting effect on the OCR were peri-operative opioids (X²(6)=62, p<0.01) and Caucasian race (X²(4)=12, p<0.02). Gender and iris color were not found to have an impact on OCR. Re-operations and first-degree relatives did not differ from age-matched controls, but EOM- and opioid-adjusted re-operations correlated with their initial cases (r=0.37).

Conclusion

We confirmed the previously published blocking effect of atropine, augmenting impact of opioids, and an inverse relationship of age on OCR. There was a weak proclivity for individuals to be prone to OCR. We found an impact of race with Caucasians having more OCR.

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Does Topical Proparacaine Improve Postoperative Comfort After Strabismus Surgery?

Background

Strabismus surgery is often performed on children and adults as a quick-turnover, outpatient procedure under general anesthesia. Ideal methods to reduce post-operative pain and nausea are not yet perfected. We postulated that a simple topical anesthetic drop after surgery might help.

Methods

In a prospective study of oculocardiac reflex (OCR) and strabismus surgery, a cohort of ongoing patients either received proparacaine immediately post-op, or none. Co-variables were Intraoperative opioid and OCR, patient age, type of surgery. Several post-operative recovery outcome variables were prospectively monitored.

Results

Sixty strabismus surgery patients (age 15±22 years) received proparacaine 1% while another 80 (16.5±22 years) received none; both received topical antibiotic-steroid ointment. Pain and nausea (Likert scale) were not impacted by covariables complexity of case, age less than 3.5, OCR >33% drop, intraoperative opioid or neuro-status. Immediate post-op heart rate was lower if OCR >33% and if opioids used. Time until discharge was shorter in younger patients. Proparacaine did not impact outcome variables, except in patients younger than 3.5 years when post-op pain was worse.

Conclusion

Post-op topical anesthetic either produced no difference, or worsened post-op pain and recovery. This prospective study does not support the use of topical anesthetic drop to reduce post-strabismus pain and nausea.

Clinical trials registration

NCT03672435, Strabismus Recovery With Proparacaine and Oculocardiac Reflex (OCRprop).

Reduction of oculocardiac reflex with Tetracaine eye drop in strabismus surgery

INTRODUCTION

Recently, to reduce the incidence of oculocardiac reflex (OCR) in strabismus surgery, retrobulbar block and anticholinergic drugs or local anesthesia are also used. The present study evaluated the effects of Tetracaine eye drop as a topical nerve blocker on OCR during strabismus surgery.

METHODS AND MATERIALS

In this randomized trial, 70 strabismus surgery candidates were randomly divided into placebo or synthetic teardrop (E) and Tetracaine eye drop (T) groups, so 3 drops of each solution were dropped in four directions of patients' eye immediately after applying anesthesia and before surgery. The incidence and severity of OCR during the stages of muscle release and incision (cutting), hemodynamic changes, the required time for OCR recovery and atropine dose were assessed.

RESULTS

OCR was more seen in release phase compared to cutting phase. There were no significant differences between two group regarding the incidence and severity of OCR in the release phase (p > 0.05), but the incidence and severity of OCR in the cutting phase was more in group E than group T (p = 0.02, for both). The duration of OCR improvement (p-value = 0.74) and Atropine consumption (p-value = 0.92) did not differ between the groups.

CONCLUSION

Tetracaine eye drop only reduces the incidence and severity of OCR during the incision stage of strabismus surgery.

The Effect of Sub-Tenon's Bupivacaine on Oculocardiac Reflex during Strabismus Surgery and Postoperative Pain: A Randomized Clinical Trial

PURPOSE

Oculocardiac reflex (OCR), defined as bradycardia induced by manipulation of extraocular muscles, is a serious complication during strabismus surgery for which prevention and proper management is required. In the present study, we investigated the efficacy of sub-Tenon injection of bupivacaine for prevention of OCR and postoperative pain.

METHODS

A prospective randomized controlled clinical trial was conducted. Fifty patients who were candidates for strabismus surgery were randomized into case (sub-Tenon's bupivacaine injection) or control (normal saline injection) groups. Standard strabismus surgery was performed for all cases. Occurrence and severity of OCR (primary outcome) and postoperative pain (using the Visual Analog Scale) were compared between the two groups.

RESULTS

Both incidence (32% vs. 100%; P = 0.002) and severity of OCR (mean heart rate decrease, 10.1 vs. 38.7 beats/minute; P < 0.001) were significantly lower in the study group compared to those in the control group. Postoperative pain scores were significantly lower in the case group than in the control group (mean score, 2.8 vs. 5.9 at 60 minutes after surgery; P < 0.001).

CONCLUSIONS

Sub-Tenon injection of bupivacaine as a local anesthetic can significantly prevent OCR and decrease the severity of bradycardia. This technique can also diminish postoperative pain in patients who underwent strabismus surgery.

Sub-Tenon's injection versus paracetamol in pediatric strabismus surgery

BACKGROUND

Emergence agitation, vomiting, and oculocardiac reflex (OCR) in children undergoing strabismus surgery under general anesthesia are common problems. The purpose of this study was to determine whether the effect of analgesia can reduce the incidence of these problems. We compared the effects of sub-Tenon's injection versus intravenous (IV) and rectal paracetamol in this surgery.

METHODS

In a prospective, randomized, double-blind study, ninety patients ranging in age from 4 to 8 years scheduled for extraocular muscle surgery for strabismus were included in this study. After induction of anesthesia, just before the surgery, children were divided into three groups (n = 30 for each group) Group A received sub-Tenon's anesthesia with 2.5% bupivacaine (0.08 ml/kg). Group B received IV paracetamol (20 mg/kg). Group C received paracetamol rectal suppository (40 mg/kg). The occurrence of oculocardiac reflex (OCR) intraoperatively was recorded. Then, in the Postanesthesia Care Unit, patients were assessed for their emergence behaviors. Vomiting was also noticed.

RESULTS

The OCR developed in few patients, and there was no significant difference between the groups. The highest number of patients with agitation was in Group C followed by Group B then Group A. Vomiting was significantly low in Group A followed by Group B then Group C.

CONCLUSION

Sub-Tenon block in strabismus surgery in children decreased the incidence of postoperative agitation and vomiting compared with IV paracetamol then rectal paracetamol. There was no difference between sub-Tenon block and paracetamol in the incidence of oculocardiac reflex.

Consensus guidelines for the management of postoperative nausea and vomiting

The present guidelines are the most recent data on postoperative nausea and vomiting (PONV) and an update on the 2 previous sets of guidelines published in 2003 and 2007. These guidelines were compiled by a multidisciplinary international panel of individuals with interest and expertise in PONV under the auspices of the Society for Ambulatory Anesthesia. The panel members critically and systematically evaluated the current medical literature on PONV to provide an evidence-based reference tool for the management of adults and children who are undergoing surgery and are at increased risk for PONV. These guidelines identify patients at risk for PONV in adults and children; recommend approaches for reducing baseline risks for PONV; identify the most effective antiemetic single therapy and combination therapy regimens for PONV prophylaxis, including nonpharmacologic approaches; recommend strategies for treatment of PONV when it occurs; provide an algorithm for the management of individuals at increased risk for PONV as well as steps to ensure PONV prevention and treatment are implemented in the clinical setting.

Sub-Tenon block does not provide superior postoperative analgesia vs intravenous fentanyl in pediatric squint surgery

PURPOSE

We evaluated the efficacy of sub-Tenon block in decreasing perioperative pain, incidence of intraoperative oculocardiac reflex (OCR), and postoperative nausea and vomiting (PONV) in pediatric squint surgery.

METHODS

A total of 67 children age 2-12 years, American Society of Anesthesiologists Physical Status 1 and 2, were randomized to receive either sub-Tenon block (ST) in the operative eye or 2 mcg/kg of intravenous fentanyl (F) for squint surgery after induction of general anesthesia in this double-blind study. Postoperative pain was measured by either modified Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) or Visual Analogue Scale (VAS). Pain in the postoperative period (up to 2 hours) was measured as the primary endpoint. Other parameters measured in the groups were intraoperative hemodynamics, postoperative modified CHEOPS or VAS at shifting, 1, 2, 6, 12, and 24 hours after surgery, incidence of intraoperative OCR, and PONV at shifting, 30 minutes, 1, 2, 6, 12, and 24 hours after surgery.

RESULTS

There was no statistical difference in the postoperative pain scores in the recovery room up to 2 hours after surgery. The VAS and CHEOPS scores were not different in the groups up to 24 hours after surgery. The incidence of OCR was significantly higher in group F than group ST. The incidence of PONV was significantly higher in group F than group ST at 30 minutes and 1 hour after the surgery (41%, 47% vs 19%, 9%, respectively, p<0.05). However, there was no statistically significant difference in intraoperative hemodynamics and PONV scores after 2 hours in the postanesthesia care unit.

CONCLUSIONS

Use of sub-Tenon block does not decrease the incidence of postoperative pain significantly in children undergoing squint surgery. However, it leads to a statistically significant decrease in the incidence of intraoperative OCR and PONV in the early recovery period in these patients.