Expanding the spectrum on brain-heart interactions in cerebellopontine angle surgeries.

Lesions at the cerebellopontine angle (CP angle) are associated with various brain-heart interactions, which can include those from stimulation of the fifth cranial nerve along the scalp incision in a retrosigmoid suboccipital surgical approach. A 27-year-old male patient with recently diagnosed hypertension (on calcium channel blocker) underwent left CP angle lesion decompression. Transient episodes of bradycardia, hypotension, and bradypnea were observed from the skin incision onward, exacerbated during tumor manipulation. Most episodes subsided with cessation of the surgical stimulus while some required intervention. Postoperatively, blood pressure decreased below the pre-operative levels. Thus, trigeminocardiac reflex can occur as early as the skin incision even in a retrosigmoid approach due to stimulation of the mandibular division, when specific risk factors exist. Such episodes may serve as early warning signs for subsequent intraoperative occurrences. Brainstem compression can be a possible etiology of hypertension in young patients. It underscores the importance of considering brain-heart interactions in surgical interventions involving the CP angle.

Perioperative adverse cardiac events in maxillofacial surgery: A systematic review and meta-analysis.

Background and Aims: Maxillofacial surgeries, including procedures to the face, oral cavity, jaw, and head and neck, are common in adults. However, they impose a risk of adverse cardiac events (ACEs). While ACEs are well understood for other non-cardiac surgeries, there is a paucity of data about maxillofacial surgeries. This systematic review and meta-analysis report the incidence and presentation of perioperative ACEs during maxillofacial surgery. Methods: We included primary studies that reported on perioperative ACEs in adults. To standardise reporting, ACEs were categorised as 1. heart rate and rhythm disturbances, 2. blood pressure disturbances, 3. ischaemic heart disease and 4. heart failure and other complications. The primary outcome was ACE presentation and incidence during the perioperative period. Secondary outcomes included the surgical outcome according to the Clavien-Dindo classification and trigeminocardiac reflex involvement. STATA version 17.0 and MetaProp were used to delineate proportion as effect size with a 95% confidence interval (CI). Results: Twelve studies (34,227 patients) were included. The incidence of perioperative ACEs was 2.58% (95% CI 1.70, 3.45, I2 = 96.17%, P = 0.001). Heart rate and rhythm disturbances resulted in the greatest incidence at 3.84% among the four categories. Most commonly, these ACEs resulted in intensive care unit admission (i.e. Clavien-Dindo score of 4). Conclusion: Despite an incidence of 2.58%, ACEs can disproportionately impact surgical outcomes. Future research should include large-scale prospective studies that may provide a better understanding of the contributory factors and long-term effects of ACEs in patients during maxillofacial surgery.

Factors associated with transient bradycardia during local anesthesia administration to the oral cavity under intravenous sedation: A retrospective cohort study.

Background/purpose: The possibility of triggering the trigeminocardiac reflex (TCR) during oral surgery is considerably lower than that during other surgeries. A reduced heart rate (HR) of ≥20% from baseline is usually considered a diagnostical criterion for the TCR. Our automated anesthesia charting system often revealed cases of slight transient HR decrease during sedation. We aimed to explore its incidence and associated factors during local anesthesia administration under intravenous sedation. Materials and methods: This study analyzed the data of 2636 cases that received infiltration anesthesia under intravenous sedation from 2008 to 2010 and had vital signs recorded using an automated anesthesia charting system. Especially, data concerning the average HR before anesthesia and the minimum HR between the initiation and end of anesthesia from anesthetic records were extracted. Moreover, data regarding patients' medical history and unusual reactions during dental treatment were collected. Multivariate logistic regression analysis was performed to identify factors associated with transient bradycardia (TB). Results: TB occurred in 472 patients (17.9%); no patient developed hypotension or any associated symptoms, suggesting that intravenous sedation was effective in stabilizing vital signs. The factors associated with TB were younger age, gag reflex, and allergy to local anesthetics. There were no differences in sex, patient history, or dose of sedatives between patients with TB and those without TB. Conclusion: The incidence of TB during infiltration anesthesia under sedation was found to be higher than that previously reported. Additionally, young age and gag reflex were identified as factors associated with bradycardia development.

Giuseppe Dagnini (1866-1928): Discoverer of the Trigemino-Cardiac Reflex and Practical Implications in Neurosurgery and Other Medical Specialties.

The authors present the life and art of Giuseppe Dagnini, a renowned Italian physician who was born in Bologna in 1866. He was the chief of the Maggiore Hospital in Bologna and authored valuable scientific works on the trigemino-cardiac reflex which is still applied in modern clinical practice. Dr. Dagnini firstly described the reflex in 1908 postulating that stimulation of one of the 3 branches of the trigeminal nerve triggers the afferent pathway in lowering heart rate. The authors also provide a modern outlook on the clinical implications of the TCR in neurosurgery, neuroanesthesia, and other medical specialties.

Heart Rate Changes following Facemask Placement in Infants Born at ≥32+0 Weeks of Gestation.

INTRODUCTION: Recent reports have raised concerns of cardiorespiratory deterioration in some infants receiving respiratory support at birth. We aimed to independently determine whether respiratory support with a facemask is associated with a decrease in heart rate (HR) in some late-preterm and term infants. METHODS: Secondary analysis of data from infants born at ≥32+0 weeks of gestation at 2 perinatal centres in Melbourne, Australia. Change in HR up to 120 s after facemask placement, measured using 3-lead electrocardiography, was assessed every 3 s until 60 s and every 5 s thereafter from video recordings. RESULTS: In the 15 s after facemask placement, 10/68 (15%) infants had a decrease in mean HR by >10 beats per minute (bpm) compared with their individual baseline mean HR in the 15 s before facemask placement. In 4 (6%) infants, HR decreased to <100 bpm. Nine out of 68 (13%) infants had an increase in mean HR by >10 bpm; 7 of these infants had a baseline HR <120 bpm. In univariable comparisons, the following characteristics were found not to be risk factors for a decrease in HR by >10 bpm: prematurity; type of respiratory support; hypoxaemia; early cord clamping; mode of birth; HR <120 bpm before mask placement. Six out of 63 infants (10%) who had HR ≥120 bpm after facemask placement had a late decrease in HR to <100 bpm between 30 and 120 s after facemask placement. CONCLUSION: Facemask respiratory support at birth is temporally associated with a decrease in HR in a subset of late-preterm and term infants.

Risk factors associated with trigeminocardiac reflex in patients with trigeminal neuralgia during percutaneous balloon compression: A retrospective cohort study.

BACKGROUND: The trigeminocardiac reflex (TCR) is a brainstem reflex commonly elicited during percutaneous balloon compression (PBC) for the treatment of trigeminal neuralgia (TN), which is characterized by drastic hemodynamic disturbances, such as bradycardia, arrhythmias and even cardiac arrest. In order to prevent catastrophic consequences, it is vital to screen the risk factors of TCR during perioperative period. The primary purpose of this study was to identify potential risk factors associated with TCR in patients with TN undergoing PBC, and to summarize the enlightenment of clinical anesthesia management. METHODS: The clinical data of 165 patients diagnosed with TN undergoing PBC from January 2021 to December 2021 were retrospectively analyzed. TCR was defined as a sudden decrease in heart rate of 20% or more compared with baseline, and / or cardiac arrest, coinciding with the stimulus of any branch of the trigeminal nerve. And a clear cause-effect relationship between heart rate reduction and PBC-related intervention was required. All demographic characteristics as well as surgical and anesthetic data were compared between TCR group and TCR-free group. Univariate and multivariate logistic regression analysis were used to further analyze TCR-related risk factors. RESULTS: Of the 165 patients enrolled in this study, 73 (44.2%) were male and 92 (55.8%) were female, and the average age was 64.22 ± 9.72 years. The incidence of TCR in the patients with TN during PBC was 54.5%. The results of multivariate regression analysis indicated that the risk factor for TCR was heart rate < 60 beats/min immediately before foramen ovale puncture (OR: 4.622; 95%CI: 1.470-14.531; P < 0.05). CONCLUSION: Heart rate < 60 beats/min immediately before foramen ovale puncture was independently associated with TCR. Therefore, it is necessary for anesthesiologists to raise heart rate appropriately to prevent TCR during PBC.

The Influence of Trigeminocardiac Reflex on Postoperative Cardiac Adverse Events in Patients Undergoing Cerebellopontine Angle Tumor Resections: A Case-Control Study.

OBJECTIVE: To assess the potential impact of the trigeminocardiac reflex (TCR) on postoperative adverse cardiac events and to identify predictors of the TCR in cerebellopontine angle surgery. METHODS: Patients undergoing elective cerebellopontine angle surgery from October 1, 2015, to September 30, 2020, were recruited consecutively for this retrospective case-control study. The TCR was evaluated by reviewing electronic anesthesia records and defined as a drop in heart rate was >20%. Controls were identified from the same retrospective cohort and matched by age, sex, and similar (±5 days) surgery date in the ratio of 1:2. RESULTS: Of 2446 patients, 68 (2.78%) experienced TCR episodes. A total of 97 TCR episodes occurred among the 68 patients. In 2 TCR episodes, severe cardiac complications developed after surgery-myocardial injury in one case and cardiac arrest in the other case. The prevalence of adverse cardiovascular events was higher in the TCR group (60.3% vs. 36.0%, P = 0.001) than in the control group. The independent risk factor for the TCR in the multivariate condition logistic regression was tumor compression of the brainstem (odds ratio = 2.36, 95% confidence interval 1.40-3.95; P = 0.001). CONCLUSIONS: Intraoperative TCR episodes seemed to be associated with postoperative adverse cardiac events in patients undergoing cerebellopontine angle surgery. Moreover, tumor compression of the brainstem might be a risk factor for TCR episodes.

Anesthesia-induced Takotsubo cardiomyopathy in trigeminal neuralgia: illustrative case.

BACKGROUND: Takotsubo syndrome (TS) represents a form of nonischemic cardiomyopathy characterized by sudden and temporary weakening of the myocardium. Many data suggest a primary role for sympathetic overstimulation in its pathogenesis. Nevertheless, these correlates are less easily identified during anesthesia. OBSERVATIONS: A 50-year-old female patient with a 4-year history of drug-resistant left trigeminal neuralgia. She was scheduled for surgical microvascular decompression. In the operating room, after induction of general anesthesia and oral intubation, the electrocardiogram revealed a significant ST segment elevation along with a sudden decrease in systolic blood pressure and heart rate. Administration of atropine caused a conversion into ventricular tachycardia. The advanced cardiac life support protocols were applied with prompt defibrillation and rapid recovery at sinus rhythm. A transthoracic echocardiogram revealed apical akinesia with ballooning of the left ventricle with a reduction of systolic function. An emergency coronary arteriography was performed, showing normal epicardial coronary vessels. After 4 days, echocardiography revealed normalization of the left ventricular function with improvement of the ejection fraction. LESSONS: In patients affected by trigeminal neuralgia, chronic pain can lead to a state of adrenergic hyperactivation, which can promote TS during the induction of general anesthesia, probably through the trigeminocardiac reflex.

Prolonged asystole induced by trigeminocardiac reflex accompanied with abnormal heart rate variability during percutaneous balloon compression: a case report.

Trigeminocardiac reflex (TCR) can result in bradycardia and even cardiac arrest, and is reversible with elimination of the stimulus. Here, we report the case of a 68-year-old man who experienced cardiac arrest during percutaneous balloon compression for the treatment of trigeminal neuralgia. In this patient, sinus rhythm did not recover after stimulation removal, causing us to successfully perform cardiopulmonary resuscitation (CPR). The patient regained a sinus rhythm and was pretreated with atropine 0.5 mg, allowing the operation to be started again. The operation was completed successfully and the patient experienced no complications. Subsequent heart rate variability (HRV) analysis showed that parasympathetic activity predominated before anesthesia induction and after tracheal intubation. It further elevated during foramen ovale puncture, leading to prolonged asystole. Fortunately, sympathetic activity predominated after atropine was administered, which manifested as an increase in sympathetic activity and a decrease in parasympathetic activity. This could be beneficial for patients with TCR. This case indicates that TCR-related cardiac arrest might not be reversed with stimulus cessation, and atropine played a key role in preventing TCR. Moreover, HRV analysis might be essential for preoperative screening for high-risk patients. We also reviewed the literature for cases of TCR with prolonged asystole.

The Effect of Trigeminal Ganglion Block on Trigeminocardiac Reflex in Elderly Patients with Trigeminal Neuralgia Undergoing Percutaneous Balloon Compression: A Randomized Controlled Study.

Background: Trigeminal neuralgia (TN) is a facial neuropathic pain, which is defined as unilateral brief shock-like paroxysmal pain. Percutaneous balloon compression (PBC) was widely used to treat TN under general anesthesia. However, trigeminocardiac reflex (TCR) as a brainstem reflex can induce bradycardia or even cardiac arrest during PBC, which may result in catastrophic consequences in elderly patients. The aim of the present study was to investigate the effect of trigeminal ganglion block on TCR in elderly patients with TN during PBC. Materials and Methods: Eighty-two elderly patients undergoing PBC were recruited to this randomized controlled study. The participants were randomly allocated to the control group (C group, n=41) and study group (S group, n=41). After anesthesia induction, 2% lidocaine 0.5 mL or an equal volume of normal saline was injected into Meckel's cave. HR and MAP were recorded at seven time-points, and the TCR incidence was compared. Results: HR decreased in the C group at the time of foramen ovale puncture (T5) and at the time of ganglion compression (T6) compared with that at the moment of needle puncture (T4) (P<0.05), but almost no change in the S group. HR was lower in the C group compared with the S group at T5 and T6 (P<0.05). MAP increased significantly at T5 and T6 compared with that at T4 in the C group (P<0.05), but almost no increase in the S group. Compared with the C group, MAP was lower at T5 and T6 in the S group (P<0.05). There were no significant differences in HR and MAP between the two groups at T1, T2, T3, T4 and T7. The incidence of bradycardia was higher in the C group than that in the S group (P<0.05). Conclusion: Trigeminal ganglion block was an effective approach to prevent TCR in elderly patients during PBC.

Repeated ventricular bigeminy by trigeminocardiac reflex despite atropine administration during superficial upper lip surgery: A case report.

BACKGROUND: The trigeminocardiac reflex (TCR) is usually caused by an increased parasympathetic tone when pressure or traction is applied to the surrounding tissue of the trigeminal nerve. However, the inexperienced anesthesiologists may have challenges on the management of TCR patients. CASE SUMMARY: This is the case of an 18-year-old woman diagnosed with hemangioma of the upper lip. During the operation, about 1 h after surgery started, a constant 1:1 premature ventricular complex was detected, and blood pressure was decreased when approaching the deeper part with more strong traction for exposure of the part. Although the management of arrhythmias, such as lidocaine and atropine, was injected, arrhythmia induced by surgical stimulation could not be eliminated completely. As the traction repeated, bradycardia was also repeated, despite injecting additional atropine. Therefore, the anesthesiologist and the surgeon decided to perform the operation only to the extent that the vascular tissue was selectively removed only at the site without the reflex. CONCLUSION: With TCR, anesthesiologists should perform appropriate monitoring. In addition to proper drug administration, surgeons should be consulted to cope with stopping the surgery and setting the scope of the surgery even if the site is superficial.

The Focus and New Progress of Percutaneous Balloon Compression for the Treatment of Trigeminal Neuralgia.

Trigeminal neuralgia is a condition confined to the trigeminal nerve, causing one or more branches of facial nerve pain. Surgical treatment options for trigeminal neuralgia include microvascular decompression(MVD), percutaneous balloon compression (PBC), radiofrequency thermocoagulation(RF), percutaneous retrogasserian glycerol rhizotomy(PRGR), gamma knife, etc. Of these treatments, PBC is increasingly being used by clinicians for trigeminal neuralgia. PBC is a simple surgical operation performed to treat trigeminal neuralgia. Owing to its advantages, PBC is favored by many clinicians. In this study, we aimed to emphasize the need to analyze the shape of the balloon, position, compression time, and pressure, as these factors can affect the efficacy of PBC. The relief of pain by balloon compression is related to the shape of the balloon on X-ray, which is the key to the operation. Owing to continued progress and advances in current imaging technologies, clinicians revealed that the precise positioning of the foramen ovale is no longer an intraoperative problem. Instead, the anatomy of Meckel's cave and the shape of the balloon must be the focus to achieve the best treatment effect. For clinicians, PBC is simple and is associated with a short operation time. PBC also has other advantages, such as low cost and immediate postoperative pain relief. The recurrence rate of pain post-PBC is low, despite the occurrence of facial numbness post-op. However, this side effect is reversible and does not affect daily life of the patient. In fact, the patient can be discharged 1-2 days after surgery. Overall, PBC can be considered as one of the preferred surgical methods for the treatment of primary trigeminal neuralgia. In this paper, we explain the main points of PBC operation in detail in terms of Meckel's cave, surgical procedure, complications, discussion of the focus and new progress, etc.

Prognostic factors for trigeminocardiac reflex during cerebrovascular intervention operation.

Introduction: Trigeminocardiac reflex (TCR) is a brainstem reflexive response of hemodynamic instability during surgery. Identification of risk factors relevant to TCR during cerebrovascular intervention procedures is helpful to efficiently prevent and treat its occurrence. The purpose of this study was to demonstrate the risk factors for Onyx embolization during cerebrovascular intervention operation so as to optimize perioperative management strategies on TCR. Methods: We performed a retrospective study on the patients with Onyx embolization under general anaesthesia over 6-years period from 2013 to 2018. 354 patients were finally eligible for inclusion, and then divided into TCR group (group T) and control group (group N). Patient characteristics, clinical diagnosis, comorbidities, lesion sites, hemodynamics changes, and complications were compared between two groups. Several multivariable regression models were applied to analyze the risk factors associated with TCR. Results: TCR occurred in 59 patients (16.7%) among 354 patients. There was no significant difference in patient characteristics between two groups (P > 0.05). During DMSO/Onyx injection, HR and MAP were much lower in group T than group N (P < 0.01). Notably, univariable analysis revealed that the patients with dural arteriovenous fistula (DAVF) and middle meningeal artery being affected were associated with a higher incidence of TCR (P < 0.01). Furthermore, multivariable analysis showed that there was a close link of TCR with DAVF [OR = 4.12; 95% CI (1.83-10.65)] and middle meningeal artery embolization [OR = 3.90; 95% CI (1.58-9.63)]. Further stratified analysis of patients with TCR found that patients with middle meningeal artery embolization were more likely to experience hypotension during TCR episode (P < 0.05). Finally, more incidence of postoperative adverse events was observed when TCR episode (P < 0.05). Conclusion: We found that DAVF and middle meningeal artery embolization were independent risk factors for TCR episodes during Onyx endovascular embolization, highly likely leading to intraoperative hemodynamics fluctuations and postoperative adverse events.

Analysis of the Hemodynamic Response During Radiofrequency Thermocoagulation in Trigeminal Neuralgia.

BACKGROUND: Radiofrequency thermocoagulation (RFT) of the trigeminal ganglion is an excellent treatment option for medically intractable trigeminal neuralgia. However, this procedure can manifest abrupt changes in cardiovascular responses. With abrupt cardiovascular changes, a sudden trigeminocardiac reflex can occur during RFT of the trigeminal ganglion. OBJECTIVES: The primary endpoint of this study was to identify the critical point at which  RFT causes abrupt hemodynamic response changes. The secondary endpoint of this study was to evaluate the occurrence of the trigeminocardiac reflex. STUDY DESIGN: Retrospective design. SETTING: An interventional pain management practice in The Republic of Korea (South Korea). METHODS: Forty patients who received trigeminal ganglion RFT under C-arm guidance due to intractable facial pain were included. We checked and recorded the blood pressure and heart rate at baseline (before RFT), immediately before and after entering the foramen ovale (FO), during electrical stimulation, during thermal heating, and 30 minutes post-RFT. Also, we recorded the presence or absence of the trigeminocardiac reflex during RFT. RESULTS: Heart rate during thermal heating increased more than 20% compared to baseline (87.6 beats/min vs 69 beats/min, P < 0.001). The mean arterial pressure showed an increase of more than 15% compared to baseline when the cannula entered the FO (106.4 mmHg vs 90.9 mmHg, P < 0.001) and during thermal heating (106.3 mmHg vs 90.9 mmHg, P < 0.001). Sudden bradycardia was observed in 25% (10/40) of the patients. Among 10 patients who showed sudden bradycardia, it was observed when the cannula entered the FO (15%, 6/40), during electrical stimulation (5%, 2/40), and during heating (5%, 2/40). LIMITATIONS: This study included 40 patients who received trigeminal ganglion RFT, which is a low number to clarify the real incidence of the trigeminocardiac reflex during RFT. CONCLUSION: FO puncturing, electrical stimulation, and thermal heating demonstrated an abrupt increase in heart rate and mean arterial pressure. The incidence of sudden bradycardia during RFT of the trigeminal ganglion was 25%. Most cases of bradycardia were observed during FO puncturing.

Perioperative trigeminocardiac reflex in patients undergoing surgical treatment of temporomandibular joint ankylosis: A study.

Purpose: The behavior of trigeminocardiac reflex (TCR) is limited to few case reports only in maxillofacial surgery, especially for temporomandibular joint (TMJ) ankylosis cases. The present study aims to find out the incidence of bradycardia due to TCR during intraoperative forceful mouth opening in TMJ ankylosis patients. Materials and Methods: A prospective, unicentric observational study was conducted selecting those patients who were planned for osteoarthrectomy with interpositional gap arthroplasty under general anesthesia. Sixty cases of TMJ ankylosis were randomly selected from December 2018 to-03-2020. Predictor variables were patient age, gender, and type of ankylosis, and outcome variables were pulse rate, mean arterial blood pressure (MABP), and oxygen saturation level (SPO2). Data were recorded at baseline and during intraoperative mouth opening via heister jaw stretcher. A Chi-square test was used for testing the association between variables. P values were considered statistically significant at <0.05. Results: The sample size of 60 subjects has been divided into two age groups (10-19) years and (20-40) years. The mean standard deviation age of the patients was 18.32 ± 6.81 years. About 63.3% were male. Out of 60 cases, 14 patients developed bradycardia. The frequency of bradycardia was found 23.3%. According to logistic regression analysis, age and type of ankylosis were the significant predictors of bradycardia. Conclusion: We conclude that bradycardia due to TCR in TMJ ankylosis patients is not an uncommon entity. Incidences are more prevalent in the age group of 10-19 years and type IV bony ankylosis. Male had a high incidence of bradycardia though P value was nonsignificant.

Trigeminocardiac reflex during maxillary third molar extraction: Our experience.

Trigeminocardiac reflex (TCR) is a cascade of physiological response secondary to the stimulation of any of the sensory divisions of the trigeminal nerve, which is the largest cranial nerve and provides sensory supply to the face, scalp, mucosa of the nose, and mouth. This response usually presents as a triad including bradycardia, apnea, and gastric motility changes. On the another side, transient loss of consciousness or vasovagal syncope, a well-known phenomenon in dentomaxillofacial surgery with its pathophysiology fully elucidated, is thought to be mediated by TCR and sometimes termed as dentocardiac reflex. Thus, it is imperative to know about TCR and its association with routine dental and maxillofacial surgery procedures. It can potentially happen during any minor or major oral surgical procedures ranging from simple third molar extractions, soft tissue surgeries, root canal treatments, or management of maxillofacial fractures. This paper presents two case reports demonstrating TCR which presented during maxillary third molar extraction and author(s) own experience in managing the same.

Case Report: Trigeminocardiac Reflex in Endovascular Recanalization of Intracranial Internal Carotid Artery Occlusion.

Background: The trigeminocardiac reflex (TCR) is a unique brainstem reflex that manifests as sudden negative hemodynamic changes. Although rare, TCR may develop during interventional neuroradiology procedures. Intracranial internal carotid artery occlusion (ICAO) is a cause or risk factor of ischemic stroke. Endovascular recanalization is an effective treatment for intracranial ICAO. The occurrence of TCR during the endovascular treatment of intracranial ICAO has not been reported previously. Methods: We identified and reviewed four intracranial ICAO cases who suffered a sudden negative hemodynamic change during endovascular therapy at our hospital between March 2019 and December 2020. Results: There were five sudden heart rate and/or blood pressure drops in the four cases; all occurred just after contrast agents were injected. Some angioarchitectural characteristics were common among the four cases. First, the intracranial internal carotid artery distal to the ophthalmic artery was occluded, leaving the ophthalmic artery as the only outflow tract. Second, there were obstructive factors proximal to the end of the guiding catheter, including a vasospasm or dilated balloon. This type of angioarchitecture with a limited outflow tract creates a "blind alley." The five negative hemodynamic events all recovered: two spontaneously and three after drug administration. Postoperatively, two of the four patients developed ocular symptoms. Conclusions: Intracranial ICAOs may produce a distinctive angioarchitecture, such as a blind alley, that predisposes patients to TCR. Surgeons should pay special attention to the possibility of TCR during the endovascular recanalization of intracranial ICAO. Low-pressure contrast injections should be attempted, and anticholinergics should be ready for use.

Severe Bradycardia Occurring After Assisted Mouth Opening: A Case Report.

We report a case of severe bradycardia during general anesthesia due to reduced atrioventricular conduction capacity believed to have been caused by the trigeminocardiac reflex (TCR). A 46-year-old woman was scheduled for intraoral scar revision under general anesthesia. When the surgeon opened her mouth intraoperatively, the patient's blood pressure immediately increased, and she developed significant bradycardia and a transient Mobitz type II second-degree atrioventricular block. It was assumed that the mandibular division of the trigeminal nerve (V-3) was stimulated by the surgeon stretching the patient's mouth open while remifentanil simultaneously provided sympatholytic effects, resulting in activation of the TCR. The patient quickly responded well to atropine and had no additional complications.