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At least 55 records · Page 3Linked to original sources
PubMed2004

Rocuronium attenuates oculocardiac reflex during squint surgery in children anesthetized with halothane and nitrous oxide.

BACKGROUND: The oculocardiac reflex (OCR) may be activated during squint surgery. The aim of this study was to test whether rocuronium 0.4 mg kg(-1) could reduce the frequency of OCR, and also whether a single dose of succinylcholine 1 mg kg(-1) could affect the frequency of OCR during anesthesia with halothane in a nitrous oxide/oxygen mixture. METHODS: A total of 161 ASA I children, 3-10 years old, undergoing elective surgery of the medial rectus muscle (MRM) were randomly assigned to three groups. Group R (n = 51), received 0.4 mg kg(-1) of rocuronium intravenously before endotracheal intubation. Group S (n = 58) received 1 mg kg(-1) of succinylcholine. Group C (controls, n = 52) received no relaxant. Oculocardiac reflex was defined as a reduction in heart rate (HR) > or = 15% and/or the appearance of any other arrhythmias, during manipulation of the MRM. Analysis of variance (anova), chi-squared, Kruskal-Wallis, and Student's t-tests were used for statistical analysis; P< 0.05 was considered statistically significant. RESULTS: In group R, OCR occurred in 15/51 (29%) of children, in group S in 31/58 (53%), and in group C in 23/52 (44%) (chi2 = 6.46, P = 0.049). In group R, the incidence of arrhythmias such as nodal rhythms, supraventricular and ventricular premature beats was 6%, compared with 22% in group S and 19% in group C (chi2 = 6.01, P = 0.040). However, there was no reduction in the occurrence of bradycardia (chi2 = 0.16, P = 0.924). CONCLUSION: Rocuronium reduced the frequency of OCR, mainly by reducing the incidence of supraventricular and ventricular premature beats.

Androstanols↗
PubMed1999

Prediction of oculocardiac reflex in strabismus surgery using neural networks.

Successfully predicting an oculocardiac reflex (OCR) is difficult to achieve despite various proposed maneuvers. The aim of this study was to test the models built up by neural networks to predict the occurrence of OCR during strabismus surgery in children. Premedication was not given. Atropine 0.01 mg/kg was medicated just before induction. Induction was performed with fentanyl or ketorolac, followed by propofol. Atracurium or vecuronium was given for intubation. Anesthesia was maintained with O2-N2O with continuous propofol infusion. Chi-square test was performed for induction agents, gender, weight, muscle blockade, repaired muscle, number of repaired muscles, duration of operation to detect any association between the occurrence of OCR and to develop the model of neural networks. The multi-layer perceptron, radial basis function and Bayesian backpropagation network were tested. The occurrence of OCR was significantly associated with gender and repaired muscle (p < 0.05). Gender, repaired muscle and age were considered as input for the multi-layer perceptron, radial basis function and Bayesian backpropagation network. Three neural networks had predicted the same correction rate in the occurrence of OCR as being 87.5% overall among 16 patients' records tested. These models are conceptually different in predicting compared to conventional maneuvers, and have the advantage of testing individually and foretelling the propensity. By comparison neural networks use grouped experiential data and predict OCR by the learning rule. Neural networks require a relatively abundant number of experienced and homogenous patients' records to establish an accurate model. The multi-layer perceptron, radial basis function and Bayesian backpropagation modeling network may be an alternative way, and preferable to vagal tone maneuvers if the associated relationships to the occurrence of OCR are more clearly defined.

Adolescent↗
PubMed1988

Asystole due to the oculocardiac reflex during strabismus surgery: a report of two cases.

The oculocardiac reflex is a well-known entity which may result in vagal depression of the heart when pressure is placed on the eyeball or when traction is applied to the extraocular muscles. Bradycardia is, by far, the most common cardiac response to these stimuli. We report two cases of ten-second episodes of asystole during traction on the medial rectus muscle as a reminder to ophthalmologists and anesthesiologists alike that this complication can and does occur during strabismus surgery.

Adolescent↗
PubMed1993

Is there a cholinergic and an adrenergic phase of the oculocardiac reflex during strabismus surgery?

We investigated the counterregulatory effect of the oculocardiac reflex (OCR) in 25 infants and children during strabismus surgery under three experimental conditions. In group 1, a series of measurements were recorded when the OCR was elicited by traction. The beat-to-beat heart rate reduction ranged from -26 to -64 beats/min (median: -46 beats/min). Constant traction increased heart rate in all patients from +23 to +50 beats/min (median: +30.5; P < 0.001). After a sudden release of the stimulation, heart rate rose further from +6 to +40 beats/min (median: +15; P < 0.001). In group 2, atropine (0.01 mg/kg) was administered 3-4 min prior to the same manipulations as in group 1. Constant traction changed heart rate from -1 to +20 beats/min (median: +4.5; P < 0.01). In group 3, a retrobulbar blockade suppressed the OCR and the counterregulation completely. These findings indicate that there is an active counterregulatory process which maintains heart rate during traction at the extraocular muscles after the bradycardic reflex has been initiated. The bradycardia and the counterregulation may be referred to as cholinergic and adrenergic phrases of the OCR. Atropine eliminates the cholinergic phase. Our study indicates that there may be receptors and afferent fibres for both phases, which can be blocked by local anaesthetics.

Adolescent↗
PubMed2004

The profound augmentation of the oculocardiac reflex by fast acting opioids.

BACKGROUND: Trigemino-vagal bradycardia elicited by tension on an extraocular muscles (oculocardiac reflex; OCR) is a hazard for strabismus surgery patients. OCR can be reduced by anticholinergic medications and regulating the depth of anesthesia. We investigated the influence of narcotic agents as a routine part of general anesthesia for strabismus surgery in adults and children. METHOD: From August, 1992 through September, 2000, 1275 patients undergoing extraocular muscle surgery were prospectively studied during 10 second, 200 gram square wave tension on gently isolated rectus muscles. The anesthetic agents, gas concentrations, and patient age were recorded. Patients receiving an anticholinergic agent and reoperated cases were excluded, yielding 1029 study cases. 849 received no narcotic as a part of induction. Two groups of patients were given no opiate before the first inferior rectus muscle was pulled. A narcotic was administered IV 5 minutes before the second inferior rectus was pulled. One group of 49 received fentanyl 0.15 uL/Kg and the second group of 12 received meperidine 1 mg/kg. RESULTS: Faster acting intravenous induction opioids had a profound augmenting effect on the degree of oculocardiac reflex. Compared to no narcotic, the OCR was increased most by remifentanyl (p less than .0001), then sufenta (p=.02), and fentanyl (p less than .0001). Induction morphine had no appreciable effect on the OCR (p=.9). For the 49 patients with IV fentanyl delivered between the first OCR and second OCR, a significant increase occurred (p=.003). This increase in %OCR was not correlated with a change in inhalational gas concentration (p=.9), CO2 concentration (p=.6) or age (p=.12). For the 12 patients given demerol between the first and second rectus tension, no significant OCR change occurred (p=.7). The OCR was greatest for inferior rectus, then superior rectus, then medial rectus, and least for lateral rectus. (See text for details.) CONCLUSION: In the absence of anticholinergic blockade, rapidly acting narcotics enhance the degree of bradycardia due to the OCR elicited by controlled extraocular muscle tension during strabismus surgery. Some opioids had the same augmenting magnitude as the blocking effect of IV anticholinergic medication. Meperidine, which has some anticholinergic characteristics, neither blocked nor augmented the OCR.

Adolescent↗