Trigeminocardiac Reflex During Temporomandibular Joint Surgery: A Systematic Review and Update for the Surgeons.

PURPOSE: Temporomandibular joint (TMJ) surgery is being increasingly performed globally with considerable success leading to improved quality of life for patients affected with disabling temporomandibular disorders. One of the most unusual phenomena noted during maxillofacial surgery due to stimulation of the trigeminal nerves is the Trigeminocardiac reflex (TCR), which causes sudden bradycardia and hypotension causing alarm and distress to the surgical and anesthetic team. The purpose of this systematic review is to identify the frequency and discuss the pathophysiology of the TCR especially during TMJ surgery. METHODS: The authors performed a systematic review by searching PubMed, Embase, Ovid, and Cochrane databases between 1946 and 2023 to identify studies that reported on the development of TCR during TMJ surgery. Non-English publications and those with inadequate details were excluded. RESULTS: Thirty-six papers reporting on the development of the TCR during oral and maxillofacial procedures were noted. Six papers reported specifically on TCR during TMJ surgery. A total of 25 subjects developed TCR during TMJ surgery. The mean age of the subjects was 31 (standard deviation 17.16) years. Twenty-three subjects (92%) developed bradycardia while 2 subjects (8%) developed asystole. All subjects recovered. The most common stimulant noted in these papers leading to TCR was manipulation and distraction of the TMJ. CONCLUSION: Although TCR is uncommon, it can occur during TMJ surgery, and it behooves the surgeon and anesthesia team to be aware of the potential for TCR to ensure adequate and timely treatment.

Intra-operative hypertension as a predictor of surgical outcomes in microvascular decompression surgery for trigeminal neuralgia.

PURPOSE: The trigeminocardiac reflex (TCR) has traditionally been characterized by a sudden decrease in heart rate, asystole, or hypotension during the manipulation of the trigeminal nerve (MTN) or its branches. While this classical TCR is well-documented, there is limited literature on alternative forms of TCR, such as the development of intraoperative hypertension (HTN) or tachycardia, and the underlying pathogenesis. Furthermore, a gap exists in understanding the correlation between intraoperative blood pressure readings and postoperative outcomes, particularly regarding pain relief in patients with trigeminal neuralgia (TN). Our study aims to examine intraoperative blood pressure trends during microvascular decompression (MVD) for TN and assess their impact on postoperative outcomes. METHODS: We selected 90 patients who underwent MVD for TN treatment. Blood pressure and heart rate were recorded both preoperatively and during the procedure, specifically during the MTN period, using an arterial line. The Barrow Neurological Institute (BNI) Pain Scale was calculated for all patients both pre- and post-operatively to evaluate pain relief after surgery. RESULTS: The mean age of the patients was 61.0 ± 12.35 years, with 64.4% being females. Classical TCR (hypotension) was observed in only 2.2% of patients, whereas 80% of patients developed hypertension (≥ 140/90) during MTN. The mean preoperative systolic blood pressure was 128 ± 22.25, and the mean intraoperative systolic blood pressure during MTN was 153.1 ± 20.2. An analysis of covariance, utilizing either preoperative BNI or duration of symptoms as covariate variables, revealed a statistically significant association between intraoperative HTN and postoperative BNI. A linear regression model demonstrated that intraoperative HTN following MTN significantly predicted a lower postoperative BNI score (p = 0.006). CONCLUSIONS: Intraoperative HTN during MTN, an observed yet underexplored phenomenon, demonstrated a correlation with improved postoperative outcomes. Furthermore, it is recommended to conduct additional investigations into potential neurovascular conflicts in patients not manifesting intraoperative HTN following MTN. A comprehensive understanding of TCR, encompassing its various forms, is vital for optimizing surgical management. This study underscores the imperative for further research to unravel the mechanisms linking intraoperative HTN to surgical outcomes in TN patients.

Trigeminocardiac Reflex: A Review and Key Implications to Dermatologic Surgery.

BACKGROUND: The trigeminocardiac reflex is a common but underreported occurrence that can vary from benign to life threatening. This reflex can be elicited by placing direct pressure on the globe of the eye or from traction of the extraocular muscles, stimulating the trigeminal nerve. OBJECTIVE: To provide a review of potential stimuli for the trigeminocardiac reflex within dermatologic surgery and to discuss management options for the treatment of the trigeminocardiac reflex. METHODS: PubMed and Cochrane were used to identify articles and case reports that established scenarios in which the trigeminocardiac reflex was provoked and subsequently how the reflex was managed. RESULTS: Within the field of dermatologic surgery, the trigeminocardiac reflex can be stimulated during biopsies, cryoablations, injections, laser treatments, Mohs micrographic surgery, and oculoplastic interventions, most often occurring in an office setting. The most common presentations include significant bradycardia, hypotension, gastric hypermobility, and lightheadedness. The most definitive treatment is cessation of the inciting stimulus, monitoring, and symptomatic management. Glycopyrrolate and atropine are common treatments for severe, intractable cases of the trigeminocardiac reflex. CONCLUSION: The trigeminocardiac reflex, while underreported and underrepresented in dermatologic literature and dermatologic surgery settings, should be considered in the setting of bradycardia and hypotension during dermatologic procedures.

Outcome of Internal Neurolysis for Trigeminal Neuralgia without Neurovascular Compression and Its Relationship with Intraoperative Trigeminocardiac Reflex.

BACKGROUND: Internal neurolysis (IN) is an effective surgical treatment for trigeminal neuralgia (TN) without neurovascular compression (NVC) or postoperative recurrence. However, the trigeminal nerve is directly manipulated during the procedure, and there is a high incidence of trigeminocardiac reflex (TCR). The aim of this study was to retrospectively analyze the outcome of IN and to explore its relationship with the occurrence of intraoperative TCR. METHODS: Surgical and anesthesia records of 27 TN patients who underwent surgical treatment with IN at our department between March 2010 and September 2016 were retrospectively analyzed. Patients were divided into 2 groups on the basis of the occurrence of TCR during surgery, and clinical characteristics were compared. Pain intensity was assessed by the Barrow Neurological Institute (BNI) pain intensity score and BNI facial numbness score. RESULTS: TCR was observed in 23 of 27 patients (85.2%); it manifested as obvious changes in mean arterial pressure and heart rate by at least 20% of the baseline values. Trigeminal nerve atrophy was found in 9 patients (33.3%). The immediate pain-free rate was 96.3%, and the "excellent" rate was 72.1% for follow-up, with a rate of numbness or hypesthesia of 97.1%. These outcomes were retrospectively compared between the TCR and non-TCR groups, and there was a nonsignificantly higher "excellent" rate in the TCR group than in the non-TCR group. CONCLUSIONS: This study demonstrated that IN is an effective treatment for TN without NVC and has a close relationship with intraoperative TCR. To our knowledge, this is the first research describing TCR during IN.

Trigeminocardiac reflex during non-surgical root canal treatment of teeth with irreversible pulpitis.

BACKGROUND/PURPOSE: Trigeminocardiac reflex (TCR) is a unique clinical incident of acute change in hemodynamic balance, which may lead to hypotension, bradycardia, and even clinical crisis. Up to date, no study so far considers the impact of non-surgical root canal treatment (NSRCT) of irreversible pulpitis teeth under either local infiltration or block anesthesia on hemodynamic change possibly related to TCR. METHODS: This study enrolled 111 patients with 138 irreversible pulpitis teeth that were treated by two sessions of NSRCT. The first session involved mainly the removal of vital pulp tissue with the direct stimulation of the dental branches of the trigeminal nerve, and the second session included the root canal enlargement and debridement with minimal disturbance to the dental branches of the trigeminal nerve. Vital signs mainly the blood pressure were recorded during both NSRCT sessions. RESULTS: The incidences of NSRCT patients with MABP decrease ≧10%, ≧15%, or ≧20% were all significantly higher in the first NSRCT session than in the second NSRCT session (all the P-values < 0.001). In the first NSRCT session, the incidence of patients with MABP decrease ≧10% was significantly associated with tooth type. For both upper and lower teeth, the patients with premolars treated by NSRCR had significantly higher incidences of MABP decrease ≧10% than those with either anterior or molar teeth treated by NSRCR (all the P-values < 0.05). CONCLUSION: We conclude that vital pulp extirpation may lead to a substantial drop in patient's blood pressure possibly related to TCR.

Autonomic responses to tooth clenching in migraineurs-augmented trigeminocardiac reflex?

BACKGROUND: Systemic autonomic changes are well known in migraineurs. Also, masticatory disorders are reported to be associated with migraine. However, if those phenomena are interrelated, and how, is unclear. Moreover, the knowledge on the autonomic responses to masticatory stimuli in migraineurs is limited. OBJECTIVE: To investigate tooth clenching-related cardiac autonomic regulation in migraineurs. METHODS: We compared maximal tooth clenching-induced systemic autonomic responses, indicated by heart rate variability and blood pressure changes, in headache-free migraineurs (n = 17) and control subjects (n = 22). RESULTS: Levels of high-frequency power, reflecting vagal activity, were lower in migraineurs at baseline but increased after tooth clenching whereas in controls they returned to baseline (P < 0.05, mixed model analysis). In multivariate regression model, the presence of migraine predicted the baseline levels of low- and high-frequency power and sympathovagal balance, and the post-test increase in high-frequency power, with the attack frequency and side of headache as the modifiers of the measured changes in migraineurs. The painful signs of temporomandibular disorders, found in clinical oral examination, enhanced both maximal changes in RR intervals and post-test vagal responses to tooth clenching only in migraineurs. CONCLUSION: The enhanced post-clenching vagal activation may represent a marker of the augmented trigeminocardiac reflex to stimulation of trigeminal area, sensitised in migraineurs. Our results support an involvement of autonomic mechanisms in migraine pathophysiology and are interesting in terms of interactions between migraine and masticatory disorders, elucidating one potential way how masticatory disorders may aggravate migraine.

Occurrence of trigeminocardiac reflex during dental implant surgery: An observational prospective study.

BACKGROUND/PURPOSE: Trigeminocardiac reflex (TCR) is a clinical phenomenon that manifests as s sudden onset of hemodynamic perturbations. TCR has been reported in cranio-maxillofacial surgery resulting in severe medical risks. Monitoring the hemodynamic changes during cranio-maxillofacial surgery can provide important information to ensure the continuous evaluation of patient's physical conditions. This prospective observational study was conducted to determine the hemodynamic alterations related to the possibly of occurrence of TCR in patients during dental implant surgery. METHODS: One hundred and thirty-five patients (69 males and 66 females) received dental implant placement were enrolled in this study. The hemodynamic changes were evaluated by monitoring heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse oximetry (SpO2). The above data were collected before, during, and after dental implant surgery. RESULTS: The data demonstrated that the minimal values of HR, SBP, and DBP as well as MABP decreased significantly during operation comparing with the corresponding values before operation (p < 0.0001). In addition, HR and SBP decreased significantly in post-operation stage comparing with the corresponding values in pre-operation stage (p < 0.0001). Comparing to dental implant placement in the mandible, patients received dental implant placement in the maxilla had more risks to confront with MABP reduction (OR = 3.98; 95% confidence interval: 1.12-13.2). CONCLUSION: A significant HR and BP reduction possibly due to TCR can occur during dental implant surgery. Therefore, the dentists should monitor the hemodynamic changes during dental implant surgery to prevent the possible occurrence of medical risks related to TCR.

[Trigemino-cardiac reflex in skull base surgery].

OBJECTIVE: To explore the mechanism, clinical features, and prognosis of Trigemino-cardiac reflex (TCR) during skull base operations. METHODS: A retrospective analysis was performed on 291 patients with skull base disease from Jan. 2009 to Oct. 2015 in Peking University First Hospital. By reviewing the patients' operative data and anaesthetic electrical record, and we picked out all the patients who suffered from TCR during the operation and analyzed their surgical procedures, clinical features, influence factors, and prognosis. TCR was defined as a drop in mean arterial blood pressure (MABP) and the heart rate (HR) of more than 20% to the baseline values before the stimulus and coinciding with the manipulation of the trigeminal nerve. RESULTS: In all the 291 patients receiving skull base surgery, 9 patients suffering TCR for 19 times during the operation were found. These 9 cases included three acoustice schwannomas, one trigeminal schwannoma, one petroclival meningioma, one epidermoid cyst in cerebellopontine angle, one cavernous sinus cavernous hemangioma, one pituitary adenoma, and one trigeminal neuralgia. The trigger of TCR was related to manipulation, retraction, and stimulation of the trunk or branches of trigeminal nerve. The baseline heart rate was 62-119/min [mean (79.4±14.6) /min] and dropped about 29.0%-66.4% (mean 44.3%) to 22-60 /min [mean (44.2±9.6) /min] after TCR. The baseline mean arterial blood pressure was 75-103 mmHg [mean (87.5±7.8) mmHg] and dropped about 23.4%-47.2% (mean 37.3%) to 45-67 mmHg [mean (54.9±6.3) mmHg] after TCR. During the 19 times of TCR, heart rate and blood pressure could return to baseline in a short time while stopping manipulation (8 times), using atropine (8 times, dose 0.5-1.0 mg, mean 0.69 mg), using ephedrine hydrochloride (one time, 15 mg), using epinephrine (one time, 1 mg), and using dopamine (one time, 2 mg). TCR also could be triggered again by a second stimulation. There was no relative cardiologic complication or neurological deficit in the postoperative 24 hours. CONCLUSION: TCR is a short neural reflex with a drop in blood pressure and heart rate coinciding with the manipulation of the trigeminal nerve in skull base surgery. Correct recognition, intensive observation, and essential management of TCR will lead to a good prognosis.

Further evidence of a prolonged hypotensive and a bradycardic effect after mandibular extension in normal volunteers.

We previously reported that in normotensive humans submaximal mouth opening (mandibular extension) obtained by an ad hoc dilator (spring device), associated with partial masticatory movements and prolonged for 10 minutes is followed by a long-lasting reduction of blood pressure (BP) and heart rate (HR). Similar results were obtained by us in anesthetized rats. A recent independent study failed to confirm the results in the normotensive human. We reassessed, in 25 normotensive volunteers, the effects on BP and HR of mandibular extension obtained by the spring device associated with partial masticatory movements compared to a control procedure, consisting in keeping a tongue depressor between the incisor teeth. Both procedures were applied for 10 minutes and systolic BP (SBP), diastolic BP (DBP) and HR were measured every 10 minutes by an automatic recorder, for 30 minutes before and 120 minutes after the procedures in seated subjects watching nature documentary films on laptop screen.Baseline levels (mean of the last 3 measurements before procedure) did not significantly differ between the experimental and control sessions. Two way repeated measures ANOVA on absolute (recorded) values did not reveal a significant main effect of treatment for SBP, DBP and HR, but a significant main effect of time (P<0.001) for BP and HR. In addition, a significant interaction of time and treatment was found for SBP (P<0.001) and DBP (P=0.005), but not for HR. In addition, two way repeated measures ANOVA was done on changes from baseline obtaining a significant main effect of treatment (P<0.001) and time (P<0.001) and a significant interaction of time and treatment for SBP (P<0.001) and DBP (P<0.01). Post-hoc comparisons revealed significantly lower values for SBP and DBP in experimental compared to control values at almost all times and this decrement was by about 5 mmHg. Furthermore, for both absolute values and changes from baseline, the interaction effect was, for BP, of a qualitative type as indicated by an opposite effect in the time-course between control and experimental sessions. This study thus provides confirmatory evidence that submaximal mouth opening for a relatively brief time is followed by prolonged albeit small reductions of BP in normotensive human volunteers.

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.

The feasibility and technical aspects of trigemino-cervical reflex elicitation in humans under general anesthesia.

OBJECTIVE: To analyze the feasibility, neurophysiological aspects, stimulation patterns, and topographic distribution of trigemino-cervical reflex (TCR) components in humans under general anesthesia. METHODS: This prospective observational study enrolled 20 participants who underwent posterior fossa surgery, surgical proceduresin thecraniovertebral junction,or spinal cord surgery. TCR responses were simultaneously recorded in the sternocleidomastoid (SCM) and trapezius muscles after electrical stimulation of the supraorbital and infraorbital nerves. TCR responses were recorded preoperatively and intraoperatively using single-pulse and multipulse (trains of 2-7 electrical stimuli) stimulation, respectively. Two stimulus duration patterns were evaluated: 0.2-0.5 ms and 0.5-1.0 ms. RESULTS: Intraoperatively, short- and long-latency TCR components were obtained in the SCM ipsilateral to the stimulation with variable recordability. Short-latency responses were the most commonly recorded components. A longer stimulus duration (0.5-1.0 ms) seems to favor the elicitation of TCR responses under general anesthesia. CONCLUSIONS: Short-latency components recorded in the SCM ipsilateral to the stimulation could be regularly elicited under general anesthesia when a larger stimulus duration (0.5-1.0 ms) was applied. SIGNIFICANCE: This is the first study to demonstrate the elicitation of TCR components in humans under general anesthesia. This neurophysiological technique can potentially optimize intraoperative neurophysiological monitoring during brainstem surgery.

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.

Unstable bradycardia induced by posterior nasal packing: a rare activation of the Trigeminocardiacreflex.

A woman in her 40s presented to the emergency department with epistaxis. Anterior nasal packing was unsuccessful in achieving haemostasis. After the exchange of devices and insertion of a posterior nasal pack, the patient developed a junctional rhythm and progressively unstable bradycardia. The rhythm and bradycardia immediately improved following the removal of the posterior nasal pack. This case describes a rare occurrence of Trigeminocardiac reflex (TCR), following an insertion of a posterior nasal pack. Only one other such case has been reported and published. This case highlights the importance of raising awareness of this rare reflex and the need for prompt removal of the triggering cause in such scenarios. TCR can induce a junctional rhythm, which progresses to unstable bradycardia and may lead to asystole in susceptible individuals. The removal of the stimulus resolves the reflex and can result in prompt resolution of the bradycardia and hypotension induced via the TCR.

Prophylactic intra-arterial injection of lidocaine: a novel strategy to prevent endovascular embolization-induced trigeminocardiac reflex.

BACKGROUND: Trigeminocardiac reflex (TCR) is a brainstem reflex that can lead to hemodynamic instability manifested as bradycardia, decrease/increase of mean arterial pressure (MAP) and, in the worst case scenario, asystole during surgery. The effective intraoperative management of recurrent and profound TCR has yet to be established. This randomized paired study was performed to identify the effect of a prophylactic intra-arterial injection of lidocaine to prevent TCR caused by Onyx embolization during cerebrovascular intervention surgery. METHODS: A total of 136 patients who received Onyx embolization under general anesthesia were assigned to a control group pretreated with intra-arterial saline injection or a lidocaine group pretreated with an intra-arterial injection of 20 mg lidocaine. Heart rate (HR) and MAP were closely monitored during the embolization procedures and the incidence of TCR, mainly characterized by a decrease in HR of ≥20%, and perioperative adverse events was recorded. RESULTS: During dimethyl sulfoxide (DMSO)/Onyx injection, HR was much slower in the control group than in the lidocaine group (p<0.05). TCR occurred in 12 patients (17.6%) in the control group (cardiac arrest in 3 patients) with decreased (7 cases) or increased (5 cases) MAP, whereas no TCR was observed in the lidocaine group. Notably, most TCR episodes occurred in patients with dural arteriovenous fistula and middle meningeal artery being affected. The composite adverse events were significantly higher in the control group than in the lidocaine group (p<0.05). CONCLUSION: This prospective study shows that a prophylactic intra-arterial injection of 20 mg lidocaine could be recommended as a novel strategy to effectively and safely prevent TCR during endovascular embolization.

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.

Sleep bruxism, an autonomic self-regulating response by triggering the trigeminal cardiac reflex.

Sleep bruxism, an intensified manifestation of rhythmic masticatory muscle activity, characterized by tooth grinding or clenching during sleep, lacks a definitive physiological purpose. This paper posits that physiologically, sleep bruxism is an autonomic self-regulatory response to nighttime occurrences of tachycardia stemming from the brain experiencing microarousals during sleep. Sleep bruxism by triggering the trigeminal cardiac reflex leads to bradycardia. Rhythmic masticatory muscle activity-sleep bruxism, thereby, serves to slow the heart rate when brain microarousals cause tachycardia.

[A case of trigeminocardiac reflex in the pterional approach].

Trigeminocardiac reflex (TCR) is a type of vasovagal reflex which happens in stimulation of the trigeminal nerve. We present a case of TCR in the pterional approach for clipping of an unruptured anterior communicating artery (Acom) aneurysm. A 69-year-old female was evaluated because of syncope. MRI showed incidentally Acom aneurysm. During the operation for clipping this aneurysm, only when we manipulated the dura attached to the sphenoid ridge, a total of three times, asystole appeared temporarily. In this case, a branch of the trigeminal nerve accompanying the middle meningeal artery was stimulated, then TCR may have been induced, leading to asystole. Furthermore, it seems that remifentanil used for anesthesia is related to TCR.

Atypical trigeminocardiac reflex during intranasal dexmedetomidine sedation of a 6-month-old premature baby.

The trigeminocardiac reflex (TCR) is an established brainstem reflex leading to parasympathetic dysrhythmias-including haemodynamic irregularities, apnoea and gastric hypermotility-during stimulation of any sensory branches of the trigeminal nerve. Most of the clinical knowledge about TCR was gathered from general anaesthesia observations, not from procedural sedation.We present a case of a 6-month-old premature baby experiencing the reflex twice under dexmedetomidine-propofol-sedation while undergoing ophthalmic and ear examination. This was interpreted as cross-over sensitisation between the facial and trigeminal cranial nerve (N V and N VII).The present case demonstrates that different TCR subtypes can occur during the same anaesthetic procedure. Triggering TCR seems to be based on several factors and not just on a single stimulus as often presumed. Therefore, for premature babies, there is a risk for TCR under procedural sedation, and we recommend using glycopyrrolate as preventive treatment.

Brain and Heart Crosstalk During Neurointerventional Procedures: The Role of the Trigeminocardiac Reflex: An Updated Systematic Review.

The trigeminocardiac reflex is a well-described brainstem reflex that clinically manifests as bradycardia, hypotension, or apnea. This physiological phenomenon is extensively reported during open neurosurgical procedures, but very few data exist for trigeminocardiac reflex occurrence during neurointerventional procedures. This systematic review aims to provide aggregated information related to the trigeminocardiac reflex during neurointerventional procedures and to improve understanding of the various mechanisms that can incite this unique brain-heart crosstalk.