Comparison of effects of thiopental, propofol or ketamine on the cardiovascular responses of the oculocardiac reflex during strabismus surgery

• Main Authors: Mohammad Reza Safavi, Azim Honarmand
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2007-10-01
• Series: Journal of Research in Medical Sciences
• Subjects: Oculocardiac reflex, strabismus surgery, ketamine, propofol, thiopental.
• Online Access: http://journals.mui.ac.ir/jrms/article/view/1122

<strong>BACKGROUND</strong>: The oculocardiac reflex (OCR), which is most often encountered during strabismus surgery in children,<br /> may cause bradycardia, arrhythmias and cardiac arrest following a variety of stimuli arising in or near the eyeball. The<br /> main purpose of this study was to evaluate the effects of various anesthetic regimens on modulation of the cardiovascular<br /> effects of the OCR during strabismus surgery.<br /> <strong>METHODS</strong>: Three hundred ASA physical status I-II patients, scheduled for elective strabismus surgery under general<br /> anesthesia, randomly allocated in a double blind fashion to one of the three anesthetic regimens: group P: propofol (2<br /> mg/kg), alfentanil 0.02 mg/kg and atracurium 0.5 mg/kg at induction; group K: ketamine racemate (2 mg/kg), alfentanil<br /> 0.02 mg/kg and atracurium 0.5 mg/kg at induction; group T: thiopental (5 mg/kg), alfentanil 0.02 mg/kg, and atracurium<br /> 0.5 mg/kg at induction. Mean arterial pressure (MAP) and heart rate (HR) were recorded just before induction, at<br /> 1, 15, 30, 45 and 60 minutes after induction. OCR was defined as a 20 beats/minute change in HR induced by traction<br /> compared with basal value.<br /> <strong>RESULTS</strong>: Mean HR (± SD) during total period of surgery in group P was significantly slower than that in group K<br /> (111.90 ± 1.10 vs. 116.7 ± 0.70, respectively; P<0.05). Mean HR changes (± SD) in group K was significantly higher<br /> than that in group P (11.2 ± 1.44 vs. 8.7 ± 1.50 respectively, P<0.05). MAP changes (± SD) was significantly lower in<br /> patients in group P compared with patients in group K or T (12.5 ± 1.13 vs. 19.3 ± 0.80 or 18.9 ± 0.91, respectively;<br /> P<0.05). Incidence of OCR was significantly lower in patients in group K compared with patients in group T or P (9%<br /> vs. 16% and 13%. Respectively; P<0.05).<br /> CONCLUSIONS: Induction of anesthesia with ketamine is associated with the least cardiovascular changes induced by<br /> OCR during strabismus surgery.<br /> <strong>KEY WORDS</strong>: Oculocardiac reflex, strabismus surgery, ketamine, propofol, thiopental.<br />