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The oculocardiac reflex: a graphic and statistical analysis in infants and children
Insights
This study introduces a new method for detecting the oculocardiac reflex (OCR) during strabismus surgery. It found that abrupt muscle tractions are more effective in eliciting the OCR, and hypercapnia can worsen it.
Area of Science:
- Ophthalmology
- Anesthesiology
- Pediatrics
Background:
- The oculocardiac reflex (OCR) is a significant concern during strabismus surgery.
- Existing methods for OCR detection may lack precision.
- Understanding factors influencing OCR is crucial for patient safety.
Purpose of the Study:
- To describe and validate a novel method for detecting and recording the oculocardiac reflex (OCR).
- To investigate the reflexogenic properties of different extraocular muscles and stimuli.
- To analyze factors influencing OCR, such as hypercapnia and ventilation, during pediatric strabismus surgery.
Main Methods:
- Developed and applied a new detection and recording method for the oculocardiac reflex (OCR).
- Studied 49 healthy infants and children undergoing strabismus surgery under halothane anesthesia.
- Applied square wave (abrupt/sustained) and slow slope (gradual) traction stimuli to 81 extraocular muscles.
Main Results:
- Square wave stimuli were significantly more effective in eliciting the oculocardiac reflex (OCR) than slow slope stimuli.
- Vagal escape and OCR fatigue were graphically documented and analyzed.
- The medial rectus muscle was not found to be more reflexogenic than other extraocular muscles; hypercapnia was identified as an important adjuvant factor.
Conclusions:
- The new method provides a more rational basis for understanding and managing the oculocardiac reflex (OCR).
- Controlled ventilation is recommended to mitigate OCR risks during strabismus surgery.
- Findings support a more evidence-based approach to preventing cardiac arrhythmias associated with OCR.
Abstract:
A new method for the detection and recording of the oculocardiac reflex (OCR) is described and applied to 49 healthy infants and children (six months to nine years old) undergoing strabismus surgery under halothane anaesthesia with spontaneous ventilation. Eighty-one extraocular muscles were studied. Square wave stimuli (abrupt and sustained tractions) were definitely more reflexogenic than slow slope stimuli (very gradual, progressive and gentle tractions). Vagal escape, as well as fatigue of the OCR, are graphically documented and analysed. In this series, using well-defined and controlled tractions, the medial rectus was not more reflexogenic than the other extraocular muscles. Hypercapnia was an important adjuvant factor of the OCR. Controlled ventilation is recommended. The routine use of intravenous anticholinergic drugs is briefly discussed. Prevention of the OCR, and prophylaxis of cardiac arrhythmias during strabismus surgery, now seem to be placed on a more rational basis.