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

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.

Chlorhexidine: An important cause of perioperative anaphylaxis

Identifying the culprit medication in cases of perioperative anaphylaxis can be extremely challenging. A detailed and accurate history, coupled with the appropriate testing, plays a key role in discovering the etiology of perioperative anaphylaxis. We present the case of a 48-year-old woman with a cranial meningioma who was scheduled for surgery. Chlorhexidine, midazolam, lidocaine, propofol, fentanyl, rocuronium, and furosemide were administered during the perioperative period. She developed hypotension, urticaria, bronchospasm, and other symptoms of anaphylaxis soon after general anesthesia. The serum tryptase level obtained during anaphylaxis was 119 ng/mL (normal, <11.4 ng/mL). Epinephrine was administered, and the surgery was canceled, with no cause identified. For the next surgical attempt, she was pretreated with diphenhydramine and ranitidine, and the neuromuscular blocker was withheld. Again, she developed hypotension consistent with anaphylaxis, and epinephrine was administered. She was referred for consultation. A detailed and accurate history was obtained. The baseline serum tryptase level was 6.4 ng/ mL. Skin-prick puncture tests were completed, and a diagnosis was made. The surgical team was instructed to avoid the culprit medication, and the cranial surgery was successful. Although difficult, cases of perioperative anaphylaxis can be solved with a detailed history, keen detective work, and appropriate testing.

Suspected Malignant Hyperthermia and the Application of a Multidisciplinary Response

Purpose: Malignant hyperthermia (MH) is a critical and potentially life-threatening emergency associated with inhaled anesthetic and depolarizing neuromuscular blocker administration. This is a single center’s response to MH. Summary: When signs of MH are observed, a page for “anesthesia STAT-MH crisis” is called, triggering a multidisciplinary response, including the deployment of a Malignant Hyperthermia Cart. The MH cart and the delegation of duties allows nurses, physicians and pharmacists to quickly understand their role in the stabilization, transition and recovery of a suspected MH patient. Conclusion: This case highlights the importance of multi-disciplinary involvement in these rare, but potentially fatal, cases.