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Effect of different anaesthetic regimes on the oculocardiac reflex during paediatric strabismus surgery
K Hahnenkamp1, C W Hönemann, L G Fischer
1Klinik und Poliklinik für Anaesthesiologie und operative Intensivmedizin, Westfaelische Wilhelms-Universitaet, Muenster, Germany.
Insights
Ketamine anesthesia resulted in fewer oculocardiac reflex (OCR) hemodynamic changes during pediatric strabismus surgery compared to propofol, sevoflurane, and halothane. This suggests ketamine may be a safer anesthetic choice for minimizing reflex-induced cardiovascular effects in this population.
Area of Science:
- Anesthesiology
- Pediatric Surgery
- Ophthalmology
Background:
- The oculocardiac reflex (OCR) is a common response to mechanical eye stimulation during strabismus surgery.
- Understanding how different anesthetic regimens affect hemodynamic responses to OCR is crucial for patient safety.
Purpose of the Study:
- To investigate the impact of four distinct anesthetic regimens on the hemodynamic effects of the oculocardiac reflex (OCR) in pediatric strabismus surgery.
- To compare the incidence and severity of OCR-induced heart rate and blood pressure changes across different anesthetic protocols.
Main Methods:
- Thirty-nine pediatric patients (4-14 years) were randomized into four groups receiving propofol/alfentanil, sevoflurane, ketamine/midazolam, or halothane.
- Hemodynamic parameters (ECG, heart rate, blood pressure) were monitored during standardized ocular muscle traction.
- OCR was defined as a 10% heart rate change induced by traction.
Main Results:
- OCR occurred in 77% of patients; incidence was lowest (22%) in the ketamine group.
- Propofol anesthesia showed significantly greater median heart rate reduction compared to halothane and ketamine.
- Ketamine anesthesia exhibited significantly different median blood pressure changes and fewer atrioventricular rhythm disorders and respiration-induced sinus dysrhythmia compared to other groups.
Conclusions:
- Ketamine anesthesia is associated with the least significant hemodynamic alterations during the oculocardiac reflex in pediatric strabismus surgery.
- Anesthetic choice significantly influences the hemodynamic response to OCR, with ketamine demonstrating a potentially protective effect.
- Further research may explore optimizing ketamine-based anesthesia for strabismus procedures to mitigate OCR-related cardiovascular instability.
Abstract:
The oculocardiac reflex (OCR) is induced by mechanical stimulation and therefore is frequently encountered during strabismus surgery. This study was designed to determine how various anaesthetic regimes modulate the haemodynamic effects of the OCR during paediatric strabismus surgery. Thirty-nine patients (4-14 years, ASA I) were randomized to one of four anaesthetic regimes: group P: propofol (12 mg.kg(-1).h(-1)) and alfentanil (0.04 mg.kg(-1).h(-1)); group S: sevoflurane 1-1.2 MAC in 30% O(2)/70% N(2)O; group K: ketamine racemate (10-12 mg. kg(-1).h(-1)) and midazolam (0.3-0.6 mg.kg(-1).h(-1); group H: halothane 1-1. 2 MAC in 30% O(2)/70% N(2)O. Electrocardiogram (ECG), beat-to-beat heart rate (HR) and blood pressure (BP) changes were measured during and after a standardized traction was applied to an external eye muscle (4-6 Newton, 90 s). OCR was defined as a 10% change in HR induced by traction. OCR occurred in 77% of patients. Whereas virtually all patients in the P, H and S groups developed OCR, only 22% developed it in group K. Median HR change in group P (-37 bpm) was significantly greater (P < 0.05) than in group H (-17 bpm) or group K (-7 bpm). Median BP change in group K (+10 mmHg) was significantly different (P < 0.05) from group H (-5 mmHg), group S (-3 mmHg) and group P (-8 mmHg). Atrioventricular rhythm disorders were significantly more frequent in group P compared with group K (P < 0.02). Respiration-induced sinus dysrhythmia was significantly less frequent (P < 0.001) in group K (0%), compared with group P (100%), group H (56%) and group S (55%). Of the anaesthetic techniques studied, ketamine anaesthesia is associated with the least haemodynamic changes induced by OCR during strabismus surgery in paediatric patients.