A randomised comparison of lidocaine 2% gel and proparacaine 0.5% eye drops in paediatric squint surgery

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.

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.

Postoperative Nausea and Vomiting in Pediatric Patients

Postoperative nausea and vomiting (PONV), postoperative vomiting (POV), post-discharge nausea and vomiting (PDNV), and opioid-induced nausea and vomiting (OINV) continue to be causes of pediatric morbidity, delay in discharge, and unplanned hospital admission. Research on the pathophysiology, risk assessment, and therapy for PDNV, OINV and pain therapy options in children has received increased attention. Multimodal pain management with the use of perioperative regional and opioid-sparing analgesia has helped decrease nausea and vomiting. Two common emetogenic surgical procedures in children are adenotonsillectomy and strabismus repair. Although PONV risk factors differ between adults and children, the approach to decrease baseline risk is similar. As PONV and POV are frequent in children, antiemetic prophylaxis should be considered for those at risk. A multimodal approach for antiemetic and pain therapy involves preoperative risk evaluation and stratification, antiemetic prophylaxis, and pain management with opioid-sparing medications and regional anesthesia. Useful antiemetics include dexamethasone and serotonin 5-hydroxytryptamine-3 (5-HT3) receptor antagonists such as ondansetron. Multimodal combination prophylactic therapy using two or three antiemetics from different drug classes and propofol total intravenous anesthesia should be considered for children at high PONV risk. "Enhanced recovery after surgery" protocols include a multimodal approach with preoperative preparation, adequate intravenous fluid hydration, opioid-sparing analgesia, and prophylactic antiemetics. PONV guidelines and management algorithms help provide effective postoperative care for pediatric patients.

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.

Prospective evaluation of anesthetic protocols during pediatric ophthalmic surgery

PURPOSE

To date, no protocol of anesthesia for pediatric ophthalmic surgery is unanimously recognized. The primary anesthetic risks are associated with strabismus surgery, including oculocardiac reflex, postoperative nausea and vomiting, and postoperative pain.

METHODS

This was a prospective, monocentric, observational study conducted in a tertiary pediatric ophthalmic unit. Our anesthetic protocol for strabismus surgery included postoperative nausea and vomiting prevention using dexamethasone and ondansetron. No drug-based prevention of oculocardiac reflex or local/locoregional anesthesia was employed.

RESULTS

A total of 106 pediatric ophthalmic surgeries completed between November 2015 and May 2016 were analyzed. The mean patient age was 4.4 (range: 0.2-7.3, standard deviation: 2.4) years. Ambulatory rate was 90%. Oculocardiac reflex incidence was 65% during strabismus surgery (34/52), 50% during congenital cataract surgery (4/8), 33% during intramuscular injection of botulinum toxin (1/3), and 0% during other procedures. No asystole occurred. Postoperative nausea and vomiting incidence was 9.6% after strabismus surgery (5/52) and 0% following the other procedures. One child was hospitalized for one night because of persistent postoperative nausea and vomiting. Postoperative pain generally occurred early on in the recovery room and was quickly controlled. Its incidence was higher in patients who underwent strabismus surgery (27%) than in those who underwent other procedures (9%).

CONCLUSION

Morbidity associated with ophthalmic pediatric surgery is low and predominantly associated with strabismus surgery. The benefit-risk ratio and cost-effectiveness of oculocardiac reflex prevention should be questioned. Our postoperative nausea and vomiting rate is low, thanks to the use of a well-managed multimodal strategy. Early postoperative pain is usually well-treated but could probably be more effectively prevented.

A double-masked randomized trial of postoperative local anesthetic for pain control in pediatric strabismus surgery

PURPOSE

To determine to what extent local anesthetic reduces postoperative pain after pediatric strabismus surgery.

METHODS

In this double-masked, randomized clinical trial of 50 children 13-91 months of age undergoing strabismus surgery, subjects were randomly assigned to one of three treatments given at the conclusion of surgery: topical lidocaine gel and sub-Tenon's (balanced salt solution) placebo (n = 16), topical placebo (hypromellose) and sub-Tenon's bupivacaine 0.75% (n = 17), or topical and sub-Tenon's placebo (n = 17). Pain was otherwise managed systemically in the usual fashion by the masked anesthesia team and assessed at regular postoperative intervals by a masked observer using an objective, validated pain scale.

RESULTS

Average pain in the first 30 minutes was 6.57, 6.36, and 6.58 in the lidocaine, bupivacaine, and placebo groups, respectively, and was significantly lower (P = 0.016) for bupivacaine vs placebo. The bupivacaine group had significantly lower scores for pain after 30 minutes, total pain, and peak pain versus the lidocaine group.

CONCLUSIONS

Sub-Tenon's bupivacaine may reduce postoperative pain in children undergoing strabismus surgery.

Comparison of topical oxybuprocaine and intravenous fentanyl in pediatric strabismus surgery

PURPOSE

To compare the outcomes such as postoperative nausea/vomiting, analgesic requirements, and hospital stay following the use of topical oxybuprocaine hydrochloride 0.4% or intravenous (IV) fentanyl in children undergoing strabismus surgery.

METHODS

This was a prospective cohort study. Children operated under general anesthesia for strabismus were given topical oxybuprocaine hydrochloride 0.4% (Group T) and IV fentanyl (Group F) before surgery. The episodes of nausea/vomiting, pain score, requirement of additional analgesia during postoperative period, and duration of hospital stay were compared in two groups.

RESULTS

There were 47 children in Group T and 59 children in Group F. The median pain score in two groups were 2.38 (25% quartile; 2.0) and 3.00 (25% quartile; 3.00), respectively. The difference was significant (K W P < 0.03). The episodes of nausea/vomiting in two groups were in 2 and 6 children in Group T and Group F, respectively. The median hospital stay of children of Group T and Group F were 242 and 285 min, respectively. The difference was not statistically significant (P = 0.22).

CONCLUSIONS

Using intraoperative topical oxybuprocaine drops, one can achieve better analgesic outcomes and reduce risk of nausea and vomiting compared to intravenous opioid analgesics and therefore, the hospital stay could also be marginally reduced.