Algorithm for pediatric orbital blowout fractures: a 20-year retrospective cohort study

Abstract Objective Pediatric orbital blowout fractures can include pathologies that seem mild but require urgent release; serious sequelae can occur with standby surgery or conservative treatment. We sought to validate an algorithm for the treatment of pediatric orbital blowout fractures. Methods This retrospective cohort study included 61 pediatric patients, aged 18 years or younger, treated for pure orbital blowout fractures according to the algorithm from April 1, 2000, to August 31, 2020, at the Japanese Red Cross Asahikawa Hospital. Results There were 52 males (85%). Median age was 14 years (range, 5-18 years). There were 9 patients categorized as needing urgent release, 16 as needing repair, and 36 as needing conservative treatment. Mean follow-up ocular movement was 98.0 (95% Confidence Interval [95% CI], 96.8-99.2). Postoperative diplopia was not observed in 96% (79.6%-99.9%) of patients, better than in previous studies. A higher proportion of patients aged 0-12 years needed urgent repair than those aged 13-18 years (Odds Ratio [OR] = 14.2; 95% CI 1.6-683.4; p= 0.0046). There were no differences in Hess area ratio by age group. Conclusion Clinical results with the algorithm were satisfactory. The algorithm is suitable for treatment of pediatric orbital blowout fractures. Level of evidence 4.

Analysis of influencing factors and countermeasures for adverse reactions after retinal laser photocoagulation / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To explore the influencing factors and coping strategies of adverse reaction after retinal laser photocoagulation.<p>METHODS: Retrospective analysis of 1 165 cases of adverse reactions in patients with retinal laser photocoagulation in our hospital.<p>RESULTS: The present study included 50 patients with adverse reactions in 1 165 patients(4.29%), including 13 patients with nausea and vomiting(1.12%), 21 patients with dizziness, chest tightness, cold sweat(1.80%), 4 cases with yawning and drowsiness(0.34%), 12 cases with syncope(1.03%), and no death. There was no difference in the incidence of adverse reactions between men and women(3.68% <i>vs</i> 5.14%, χ2=1.474, <i>P</i>=0.225); there was a difference in the incidence of adverse reactions among patients of different ages(χ2=48.817, <i>P</i><0.05)and under 40. The incidence of adverse reactions was higher than that of patients aged 40 and older, and the incidence of adverse reactions in men under 40 was significantly lower than that in women(8.46% <i>vs</i> 18.60%, χ2=6.094, <i>P</i>=0.014). The adverse reactions of patients with different fundus diseases were different.<p>CONCLUSION: The incidence and degree of postoperative adverse reactions in patients with fundus diseases treated by retinal laser photocoagulation are different, so we should understand the history and mental state of the patients in detail before operation, and prepare the patients with high risk factors and possible serious reactions in time to ensure the safety of the patients.

Influence of retrobulbar anesthesia or atropine pretreatment before strabismus surgery for oculocardiac reflex in children / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To assess the effect of applying retrobulbar anesthesia or atropine pretreatment as an available method to prevent oculocardiac reflex(OCR). <p>METHODS:A total of 92 pediatric patients(166 eyes)aged 5-13 years old who underwent elective strabismus surgery from March 2015 to March 2016 were enrolled and randomly assigned into three groups. Traditional anesthesia(TA)group was intravenously injected with propofol 2 mg/kg, fentanyl 1 mg/kg and atracurium 0.5mg/kg. Retrobulbar anesthesia(RA)group received both traditional anesthesia and retrobulbar injection of 2% lidocaine 2mL. Atropine pretreatment(AP)group received both traditional anesthesia and intravenous injection of atropine 0.15 mg/kg before surgery. The heart rate decreased by over 10% from the baseline value was considered as OCR positive. The anesthesia time, operation time, the baseline value of heart rate and the muscles induced OCR were recorded and analyzed. <p>RESULTS:The incidence of intraoperative OCR was 20% in RA group, 22% in AP group and 58% in TA group. There was no significant difference in anesthesia time, operation time, the baseline value of heart rate and corrective rate of postoperative eye position among three groups(<i>P></i>0.05). <p>CONCLUSION: Retrobulbar anesthesia and atropine pretreatment both effectively reduced the incidence of OCR in children's strabismus surgery, which could be potentially effective methods to prevent OCR and further provide more operation security for children with strabismus.

Efectos cardiorespiratorios y requerimientos de isofluorano en conejos sometidos a cirugía oftalmológica tratados con tramadol pre, intra y postoperatorio / Cardiorespiratory effects and isoflurane requirements in rabbits subjected to ophthalmologic surgery treated with tramadol pre-, intra- or postoperatively

Para evaluar los efectos cardiorespiratorios y los requerimientos de isofluorano en conejos sometidos a cirugía oftálmica tratados en diferentes momentos con tramadol, fue realizado un estudio prospectivo experimental de tipo ciego en 24 conejos distribuidos aleatoriamente en tres grupos de ocho individuos cada uno: grupo tramadol preoperatorio (Tpre), grupo tramadol transoperatorio (Ttrans) y grupo tramadol postoperatorio (Tpos). Cada animal recibió tres inyecciones intramusculares de igual volumen en los periodos pre, intra y postoperatorio, conteniendo tramadol (4mg/kg) o NaCl 0,9%, de acuerdo al momento indicado para cada grupo. La inducción y mantenimiento anestésico fueron realizados con isofluorano en FiO2 1,0. Una vez estabilizado el plano anestésico, fue iniciado el procedimiento quirúrgico. Se evaluaron: frecuencia cardíaca (FC), presión arterial media (PAM), frecuencia respiratoria (f), presión de CO2 al final de la expiración (EtCO2), saturación parcial de oxihemoglobina (SpO2) y concentración de isofluorano al final de la expiración (EtISO). Las variables fueron medidas después de la estabilización anestésica (m1) y cada 10 min desde el inicio de la cirugía, hasta el final del experimento (m10 a m40). La FC, SpO2, f , EtCO2 y EtISO fueron similares entre grupos durante todo el tiempo. La PAM fue significativamente mayor (p<0,01) durante m1 comparada con el resto del tiempo y el grupo Tpre mostró valores inferiores (p=0,04) de este parámetro durante m1 con relación a los demás grupos. El clorhidrato de tramadol promueve la reducción transitoria de la presión arterial en conejos anestesiados con isofluorano y sometidos a cirugía oftálmica. La administración preoperatoria del fármaco no disminuye el requerimiento anestésico y resulta en hipotensión más pronunciada. Adicionalmente, la anestesia con isofluorano, asociada al reflejo óculo-cardiaco, generan hipotensión arterial, fenómeno que debe tenerse en cuenta durante cirugías oftalmológicas.

To evaluate the cardiorespiratory effects and isoflurane requirements of tramadol applied at different times during ophthalmic surgery, a blind prospective study was made in 24 rabbits, randomly divided into three groups of eight subjects each: pre-operatory tramadol group (Tpre), trans-operatory tramadol group (Ttrans) and post-operatory tramadol group (Tpos), which received three intramuscular injections of equal volume, in the pre, intra and post-operative period, containing tramadol hydrochloride (4 mg/kg) or NaCl 0,9%, according to each group. Anesthetic induction and maintenance was made with isoflurane diluted FiO2 1.0. Once the anesthetic plane was stabilized, surgical procedure was started. Were evaluated heart rate (HR), medium arterial presseure (MAP), respiratory rate (f), end tidal CO2 (EtCO2), Oxihemoglobin saturation (SpO2) and end tidal isoflurane (EtISO). Variables were measured after anesthesia stabilization (m1) and every 10 min after onset of surgery, until the end of experimental protocol (m10 to m40). HR, SpO2, f, EtCO2 and EtISO were similar among groups at all times. MAP were significantly higher (p<0.01) in m1 than in other moments and Tpre group showed lower (p=0.04) values than the other groups at this moment. Tramadol hydrochloride promotes transient reduction of blood pressure in isoflurane anesthetized rabbits subjected to ophthalmic surgery. The preoperative administration of the drug does not reduce the anesthetic requirement and results in a more pronounced hypotension. Additionally, isoflurane anesthesia, associated to oculocardiac reflex generates a hypotension phenomenon that must be taken in to considertation during ophthalmologic surgeries.

Effect of ketamine and midazolam on oculocardiac reflex in pediatric strabismus surgery / 대한마취과학회지

BACKGROUND: The oculocardiac reflex (OCR) can be elicited during manipulation of the orbital structures in the strabismus correction surgery. A sinus bradycardia is the most common manifestation of OCR; and cardiac dysrhythmia and asystole may also occur. Various efforts to reduce OCR have been attempted, but without coherent outcome results. METHODS: Sixty one children, undergoing elective strabismus surgery, were randomly allocated into 2 groups: Group K received ketamine 1.0 mg/kg; and Group M received midazolam 0.15 mg/kg for induction of anesthesia. Anesthesia was maintained with 1-1.3 MAC of sevoflurane with 50% N2O in O2. Heart rate and blood pressure were measured 30 seconds before extraocular muscle (EOM) traction and immediately after traction. The OCR was defined as a decrease in heart rate more than 20% of the baseline heart rate, following manipulating EOM. Postoperative nausea and vomiting (PONV) and emergence agitation (EA) were assessed in postanesthetic care unit (PACU). RESULTS: Blood pressure before tightening EOM in Group K was higher than that in Group M (P < 0.05). However Delta HR (2.7 +/- 15% vs. - 0.9 +/- 16%) and incidence of OCR (10.0% vs. 19.4%) after traction an EOM were not different between the two groups. The occurrence of PONV (6.7 vs. 9.7%) and EA (30.0% vs. 22.6%) were similar. CONCLUSIONS: Ketamine does not reduce the incidence of OCR compared with midazolam in pediatric strabismus surgery. In addition, ketamine does not increase the incidence of PONV and EA. In conclusion, it is reliable to use ketamine in pediatric strabismus surgery.

Recognition of oculocardiac reflex / 中华实验眼科杂志

The oculocardiac reflex (OCR) occurs in up to 90% of ophthalmological surgeries,while most of the clinicians consider the performance of OCR is just bradycardia and arrhythmia and therefore ignore other system manifestation such as oculorespiratory reflex( ORR) and oculo-emetic reflex(OER),and so on.OCR appears not only in ophthalmological surgeries,and it also occurs during the endoscopic sinus surgery.A unstable bradycardia associated with stimulation of the mandibular division of cranial nerve V during trigeminal neuralgia pain treatment is also reported.This phenomenon is mostly introduced only as clinical manifestations.Therefore,it is helpful for us to understand the essential characteristic of OCR.The embryonic,anatomy,physiology and electrophysiology were reviewed in this article and thought to term it as oculovagal reflex is more comprehensive.

Anesthetic management of ophthalmic surgery / 대한마취과학회지

Ophthalmic surgery presents challenges for the anesthesiologists, including control of intraocular pressure, prevention and management of the oculocardiac reflex. In addition to understanding ocular anatomy and physiology, the anesthesiologists must have possess technical expertise and knowledge of ophthalmic drug's systemic effects. Patients undergoing ophthalmic surgery have extremes of age and several medical diseases, like as hypertension, diabetes mellitus, coronary heart disease, chronic renal failure, and chronic obstructive lung disease. Anesthesiologist should be knowledgeable about the content as stated above to perform safe and desirable anesthesia for ophthalmic surgery.

Influence of topical anesthetics on oculocardiac reflex and corneal healing in rabbits / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the incidence of oculocardiac reflex (OCR) with two anesthetic regimens and its prevention using topical anesthetics in a rabbit model. We also investigated the effect of topical anesthetics on corneal healing.METHODS: Forty-eight clinically healthy adult New Zealand white rabbits of either sex were divided into two groups (Group A and B) and anesthetized with either ketamine (Group A, n=24) or propofol (Group B, n=24). In this study , the incidence of OCR was recorded in each group with a variety of ocular manipulation with or without the use of topical anesthetics (40g/L lignocaine, 5g/L proparacain, 5g/L bupivacaine). Corneal toxicity and healing following the use of each topical anesthetic was assessed one day after surgery and up to 7 days postoperatively by clinical examination of the eye, histopathology and collagen staining and transmission electron microscopy.RESULTS: No incidence of OCR was recorded with ocular manipulation under ketamine anesthesia, whereas significant reduction in heart rate (P<0.01) was recorded under propofol anesthesia. Topical anesthetics could successfully prevent the OCR without affecting the corneal healing.CONCLUSION: Topical anesthetics may be recommended for prevention of OCR without any local adverse effect.

Oculocardiac Reflex during Endoscopic Sinus Surgery: A case report / 대한마취과학회지

The oculocardiac reflex is provoked by pressure applied to the globe of the eye or traction on the surrounding structures. It has been known that children and adults undergo eye muscle surgery under general anesthesia are most susceptible. When it occurs the most common manifestation is sinus bradycardia and other arrhythmia including atrioventricular block, ventricular premature beat and cardiac arrest. Endoscopic sinus surgery has been used popularly for treatment of chronic paranasal sinusitis. However endoscopic sinus surgery can be difficult for narrow visual field and anatomical variations. Oculocardiac reflex during endoscopic sinus surgery is rare case but potentially it can be life threatening event. The authors report the case of oculocardiac reflex during endoscopic sinus surgery with a review of literature.

A Case of Oculocardiac Reflex During Endoscopic Sinus Surgery / 대한이비인후과학회지

Endoscopic sinus surgery has been used popularly for treatment of chronic paranasal sinusitis. Sometimes endoscopic sinus surgery is complicated by narrow visual field and anatomical variations. Oculocardiac reflex is developed by surgical or nonsurgical procedures to the eyeball. It occurs because of decreasing of heart rate and other arrhythmia including atrioventricular block, ventricular premature beat and cardiac arrest. Oculocardiac reflex during endoscopic sinus surgery is unusual and it is potentially a life threatening complication. The authors report the first case of oculocardiac reflex experienced during endoscopic sinus surgery in Korea with a review of the literature.

Clinical Analysis of Internal Orbital Fractures in Children

In order to describe the demographics, etiologic and clinical factors, and outcomes of orbital fractures in children, we have reviewed a case series of 17 patients under 18 years of age with internal orbital fractures (i.e., without involvement of the orbital rim) presenting to the Ghil hospital between March 2000 and June 2001. For 15 of the patients, we performed orbital wall reconstruction with Medpor (R) barrier sheet implantation (thickness 1mm) through transconjunctival approach under endoscopic guidance, while maintaining mere observation on the other 2 patients. There were 14 male and 3 female patients. The most common cause of fractures was accident (7 cases). Inferior wall involvement was most commonly seen, and the trapdoor type fracture was the most common. Thirteen patients had extraocular muscle restriction, 9 had nausea/vomiting and 5 had bradycardia. Diplopia of 9 patients disappeared after 43+/-23 days. Nausea/vomiting and bradycardia disappeared rapidly after surgical intervention in all cases. These results suggest that trapdoor fractures with soft tissue entrapment are the most common in pediatric orbital wall fractures, and that most of them are associated with nausea/vomiting. We suggest that early diagnosis, and prompt surgical intervention are required for those patients with oculocardiac reflex.

Oculocardiac Reflex during Strabismus Surgery

PURPOSE: To investigate the factors that influence development of oculocardiac reflex (OCR) during strabismus surgery and to discuss the preventive strategies. METHODS: We examined patients undergoing surgery for strabismus. One hundred and sixty extraocular muscles of 73 patients were operated and 114 extraocular muscles of 50 patients who were operated under general anesthesia were evaluated. We investigated the incidence of the OCR and subsequent postoperative vaso-vagal response (VVR). RESULTS: An overall rate of 74.0% of the patients and 53.8% of the muscles showed a positive OCR. Under general anesthesia, 74.0% of the patients and 50.9% of the muscles showed a positive OCR. There was a significant difference in the frequency of OCR between the medial rectus and the other muscles (p=0.009). The development of OCR is frequent during muscle traction in strabismus surgery. There was a significant association between positive OCR and subsequent postoperative VVR (p=0.039). CONCLUSIONS: The predictive factors of the OCR during strabismus surgery under general anesthesia were muscle type and procedure. Therefore cardiac monitoring during the operation is needed and gentle manipulation of the extraocular muscles is important especially when the medial rectus muscle. The estimation of OCR will be helpful for prevention of subsequent postoperative VVR.

Effects of Gallamine, Vecuronium and Rocuronium on Oculocardiac Reflex, Blood Pressure and Heart Rate in Pediatric Strabismus Surgery / 대한마취과학회지

BACKGROUND: Intraoperative oculocardiac reflex (OCR) is a common problem of pediatric strabismus surgery and potentially fatal as it can cause cardiac arrest. The goal of this study was to assess the effects of gallamine, vecuronium and rocuronium on the oculocardiac reflex, blood pressure and heart rate in pediatric strabismus surgery. METHODS: Ninety healthy children undergoing strabismus surgery were randomly assigned to three groups; gallamine, vecuronium or rocuronium group. All children were under general anesthesia induced with thiopental sodium and received gallamine 3 mg/kg, vecuronium 0.1 mg/kg, or rocuronium 0.8 mg/kg as a muscle relaxant, and were maintained with sevoflurane in 50% nitrous oxide. Systolic blood pressure, diastolic blood pressure, and heart rate were measured before anesthesia, before the operation, before traction and after traction of the ocular muscle. The OCR was defined as a 20% or greater decrease in heart rate from before traction of the ocular muscle. RESULTS: Compared with three groups, there were decreased incidences of OCR and increased heart rate at before the operation, before traction and after traction in the gallamine group (P<0.05). Systolic blood pressure and diastolic blood pressure were no differences occurred among three groups. CONCLUSIONS: We found that the gallamine group results in decreased incidences of OCR and increased heart rate were comparable with three groups.

Correlation between Respiratory Rates and the Degree of Bradycardia in Strabismus Surgery in Children / 대한마취과학회지

BACKGROUND: Strabismus surgery is frequent in pediatric ophthalmic surgery. Traction on the extra ocular muscles can trigger an oculocardiac reflex. We investigated the correlation between respiratoy rates and the degree of bradycardia to find another management for preventing oculocardiac reflex. METHODS: No premedications were administered. They were induced with thiopental and vecuronium and maintained with O2-enflurane-N2O. The tidal volume was 10 ml/kg. Respiratory rate of group 1 (n = 18) was fixed at 24 bpm, group 2 (n = 18) at 20 bpm, and group 3 (n = 19) at 16 bpm. We measured the mean heart rate from intubation to the beginning of surgery and defined this as the basal heart rate. We defined the lowest heart rate after traction of the extraocular muscles as the minimal heart rate. We calculated the correlation coefficient between the respiratory rate and basal heart rate, minimal heart rate, the change of heart rates and EtCO2. RESULTS: There was a positive correlation between the respiratory rate and the basal heart rate, and minimal heart rate. There was no correlation between the respiratory rate and the change of heart rate. There was no difference in EtCO2 among the 3 groups. CONCLUSIONS: Can be increased both basal heart rate in anesthetized patients and minimal heart rate induced by oculocardiac reflex by making the respiratory rate more rapid if there is no significant difference of EtCO2. The oculocardiac reflex may be reduced by making respiratory rate more rapid if there is no significant influence on minute ventilation.

Correlation between Respiratory Rates and the Degree of Bradycardia in Strabismus Surgery in Children / 대한마취과학회지

BACKGROUND: Strabismus surgery is frequent in pediatric ophthalmic surgery. Traction on the extra ocular muscles can trigger an oculocardiac reflex. We investigated the correlation between respiratoy rates and the degree of bradycardia to find another management for preventing oculocardiac reflex. METHODS: No premedications were administered. They were induced with thiopental and vecuronium and maintained with O2-enflurane-N2O. The tidal volume was 10 ml/kg. Respiratory rate of group 1 (n = 18) was fixed at 24 bpm, group 2 (n = 18) at 20 bpm, and group 3 (n = 19) at 16 bpm. We measured the mean heart rate from intubation to the beginning of surgery and defined this as the basal heart rate. We defined the lowest heart rate after traction of the extraocular muscles as the minimal heart rate. We calculated the correlation coefficient between the respiratory rate and basal heart rate, minimal heart rate, the change of heart rates and EtCO2. RESULTS: There was a positive correlation between the respiratory rate and the basal heart rate, and minimal heart rate. There was no correlation between the respiratory rate and the change of heart rate. There was no difference in EtCO2 among the 3 groups. CONCLUSIONS: Can be increased both basal heart rate in anesthetized patients and minimal heart rate induced by oculocardiac reflex by making the respiratory rate more rapid if there is no significant difference of EtCO2. The oculocardiac reflex may be reduced by making respiratory rate more rapid if there is no significant influence on minute ventilation.

Oculocardiac Reflex and Postoperative Recovery in Pediatric Strabismus Surgery: A Randomized Trial Comparing Four Anesthetic Techniques / 대한마취과학회지

BACKGROUND: Oculocardiac reflex (OCR) and postoperative nausea/vomiting are major complications of pediatric strabismus surgery. The aim of the study was to assess, in children undergoing strabismus surgery, the incidence of OCR and postoperative emesis with a inhalational and a intravenous technique. METHODS: 44 healthy children undergoing elective strabismus surgery as inpatients were randomly allocated to four anesthetic techniques: (1) induction with propofol, maintenance with propofol infusion and 50% N2O-O2 (propofol-N2O); (2) induction with propofol and fentanyl 1 microgram/kg bolus, maintenance with propofol infusion and 50% air-O2 (propofol-fentnyl-air); (3) induction with thiopental, maintenance with enflurane and 50% N2O-O2 (enflurane-N2O); (4) induction with thiopental and fentanyl 1 microgram/kg, maintenance with enflurane and 50% air-O2 (enflurane-fentanyl-air). RESULTS: The incidence of an OCR significantly increased in the propofol-fentanyl-air group as compared to the enflurane-N2O or enflurane-fentanyl-air groups. Times to extubation were shorter in the propofol- N2O group than in the propofol-fentanyl-air or enflurane-fentanyl-air groups. Alertness scores were lower in the propofol-N2O group than in the enflurane-N2O or enflurane-fentanyl-air groups. Postanesthetic recovery scores and nausea/vomiting during the 24 hr after the operation did not show any differences among the groups. CONCLUSIONS: We concluded that children undergoing strabismus surgery anesthetized with propofolfentanyl-air had more episodes of OCR, propofol-N2O had shorter times to extubation and higher alertness scores, and the addition of N2O or fentanyl to anesthetic regimen was not associated with nausea and vomiting.

Comparison of Two Anesthetic Techniques (Propofol with and without Nitrous Oxide) on Oculocardiac Reflex and Postoperative Nausea and Vomiting in Pediatric Strabismus Surgery / 대한마취과학회지

BACKGROUND: Intraoperative oculocardiac reflex (OCR) and postoperative nausea and vomiting (PONV) are common problems of pediatric strabismus surgery. Propofol is thought to increase the incidence of OCR in spite of profound antiemetic effect. The goal of this study was to assess, in pediatric strabismus surgery, the incidence of OCR and PONV in a propofol with and without nitrous oxide (N2O) anesthesia. METHODS: Children (1~14 yr.'s) undergoing strabismus surgery as in patients were randomly allocated to two anesthetic techniques: propofol with 60% N2O and propofol with air instead of N2O. All children received iv fentanyl 2 microgram/kg, atropine 0.015 mg/kg and 1% lidocaine 1.5~2 ml before propofol 2.5 mg/kg injection. Anesthesia was maintained with three stage infusion method of propofol with and without N2O by groups after intubation with atracurium 0.4 mg/kg. A significant OCR was defined as an acute decrease in heart rate of 20% or greater associated with traction on an ocular muscle. RESULTS: Data on 224 children were analyzed. An intraoperative OCR was elicited in 41 (36.9%) of the 111 children in the N2O group and in 66 (58.4%) of the 113 children in Air group, while 14 (12.6%) and 12 (10.6%) developed PONV in the N2O group and the Air group in the subsequent 24 hr. period. The OCR was more frequent during medial rectus muscle correction (62.5%) than in lateral rectus muscle correction (39.5%). There was no significant correlation between OCR and PONV. CONCLUSIONS: We conclude that propofol with N2O anesthesia was effective in reducing the incidence of intraoperative OCR with a similarly excellent postoperative antiemetic effect in pediatric strabismus surgery compared to propofol without N2O anesthesia.

Relationship between Nausea, Vomiting and Oculocardiac Reflex Developing after Strabismus Surg e ry under Topical Anesthesia

Stimulation of trigeminal nerve by traction of extraocular muscle during strabismus surgery induces various vagal symptoms such as oculocardiac reflex, nausea and vomiting. We have investigated the incidence and severity of nausea and vomiting in the patients who underwent strabismus surgery under topical anesthesia and relationship with oculocardiac reflex. Among 40 patients, 16 patients(40%) complained of moderate to very severe degree of nausea and vomiting during or after surgery, and the severity of emesis increased in proportion to frequency of oculolocardiac reflex. These results suggest that so many patients would feel discomfort after strabismus surgery under topical anesthesia, and that estimation of oculocardiac reflex will be helpful in prediction of such symptoms and in taking preventive measure in advance.

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.

Response of Patients in Strabismus Surgery under the Topical Anesthesia

Local anesthesia in strabismus surgery allows for the evaluation of ocular alignment during the operation and enables early postoperative recovery.However, extraocular muscle traction results in decreased heart rate and discomfort for the patient. Therefore, it is our attempt to reveal the degree of of decreased heart rate during extraocular muscle traction and the patient`s pain perception. This was done prospectively on personalities of the patient, preoperative heart rate in the operating room, change of heart rate and pain perception of the patient during surgery. The statistically significant decrease in heart rate due to the ocular cardiac reflex occurs during medial rectus resection, lateral rectus recession, and leads to less satisfaction in the anxious patients. Strabismus surgery under topical anesthesia does not decrease the heart rate significantly, therefore it is relatively safe and the patient`s personality was influence on the intraoperative pain perception of the patients.