Factors Affecting Oculocardiac Reflex Incidence In Pediatric Strabismus Surgery: Retrospective Study

Abstract

INTRODUCTION: Oculocardiac reflex (OCR) activation is common during the strabismus surgery. As a result of the OCR, sinus bradycardia, atrioventricular block, ventricular fibrillation and even asystole may occur. Pediatric patients are also more vulnerable to harmful effects of this reflex. The aim of this study was to determine the possible risk factors affecting the incidence of OCR in pediatric patients undergoing strabismus surgery. METHODS: The medical records of the pediatric patients who underwent strabismus surgery between January 2015 and September 2018 were retrospectively reviewed. Operations performed by only one surgeon. OCR was defined as a more than 20% reduction in HR induced by the extraocular muscle (EOM) manipulation. Demographic data, duration of surgery, history of any previous strabismus surgery and possible development of OCR, anesthesia management, neuromuscular blocker and anesthetic drugs used for the anesthesia induction and maintenance as well as the airway management, the number of operated eyes, and also the muscle types of the patients were all recorded. Risk factors for OCR were evaluated by logistic regression analysis. RESULTS: Out of 92 pediatric patients who were initially evaluated, six were excluded from the study because their files were missing. A total of 86 patients were included in the study. During surgery, OCR occurred in 29 (33.7%) patients. The absence of administering benzodiazepine for premedication (p=0.03) and neuromuscular blocker after induction (p=0.046) in pediatric patients are specified as independent risk factors. We found that the use of a neuromuscular blocker and benzodiazepine in premedication reduced the risk of OCR by 3.64 and 3.11 times, respectively. DISCUSSION AND CONCLUSION: The incidence of OCR may decrease with preventive measures such as neuromuscular blocker application, premedication with benzodiazepine in strabismus surgeries.

The Oculocardiac Reflex: A Review

“… 21 In a recent retrospective logistic regression analysis of strabismus surgery in children, the 37 who received rocuronium were 3.1 times less likely to have 20% OCR than the 49 who did not get neuromuscular blockade. 85 …”

“… 131 Jean et al reviewed regional anesthesia for eyes suggesting that dexmedetomidine “increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events.” 132 In a retrospective study of strabismus surgery in children, the 34 who received pre-induction IV midazolam were 3.6 times less likely to have 20% OCR than the 52 who did not get it. 85 …”

“… 74 Fourteen of 86 strabismus children had chronic diseases cerebral palsy and asthma and were ASA II, but they did not have increased risk of OCR (p=0.08) by regression analysis. 85 …”

Hydroxyzine dihydrochloride premedication is a necessity for pediatric patients undergoing strabismus surgery: An observational prospective clinical trial

“…It has been reported that increased anesthesia depth in uences subcortical areas and prevent the development of OCR through the suppression of nociceptive and autonomic re exes (9) and that OCR can be prevented by retrobulbar block and with anticholinergic medications (1). Several studies in the literature have investigated the effects of using various anesthetic agents in pediatric strabismus surgery on the incidence of OCR.…”

“…According to the results of these studies; propofol or remifentanil anesthesia was associated with a higher incidence of OCR compared to sevo urane and des urane when midazolam was used as the induction agent (10); dexamethasone administered as nasal prophylaxis increased the rate of OCR (11); ketamine and midazolam showed similar effects and did not reduce the incidence of OCR (12). On the other hand, not administering neuromuscular blockers and premedication with benzodiazepine have been reported to reduce the risk of OCR by 3.64 and 3.11 times, respectively (9). In addition, atropine premedication has been reported to reduce OCR and prevents undesired effects of dysrhythmias (13).…”