Transient asystole during endoscopic transsphenoidal surgery: an example of trigeminocardiac reflex

The clinical surrogate definition of the trigeminocardiac reflex: Development of an optimized model according to a PRISMA-compliant systematic review

BACKGROUND

The trigeminocardiac reflex (TCR) is defined as sudden onset of parasympathetic dysrhythmias including hemodynamic irregularities, apnea, and gastric hypermotility during stimulation of sensory branches of the trigeminal nerve. Since the first description of the TCR 1999, there is an ongoing discussion about a more flexible than the existing clinical definition. Aim of this work was to create a clinical surrogate definition through a systematic review of the literature.

METHODS

In this meta-analysis study, literature about TCR occurrences was, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement, systematically identified through various search engines including PubMed (Medline), Embase (Ovid SP), and ISI Web of Sciences databases from January 2005 to August 2015. TCR was defined as a drop of heart rate (HR) below 60 bpm or 20% to the baseline. We extracted detailed data about hemodynamic changes and searched for connections between arterial blood pressure (BP) and HR changes during such episodes.

RESULTS

Overall 45 studies harboring 57 patients were included in the study but only 32 patients showed sufficient data for final analyze. HR showed a nonlinear behavior with a "tipping point" phenomena that differs in variance from the central/peripheral (20-30% drop) to ganglion (40-49% drop). BP showed a linear behavior with a "central limit" phenomena not differing in variance in the whole subgroup (30-39% drop). An analyzation of the correlation between BP and HR showed a trend to a linear correlation.

CONCLUSIONS

We can show for the first time that HR is the dominant variable in the TCR and present a new surrogate definition model. This model and the role of BP must be better investigated in further studies.

Functional Outcome Changes in Surgery for Pituitary Adenomas After Intraoperative Occurrence of the Trigeminocardiac Reflex: First Description in a Retrospective Observational Study

Trigeminocardiac reflex (TCR) represents now a nearly ubiquitary phenomenon in skull base surgery. Functional relevance of the intrainterventional TCR occurrence is hitherto only proven for vestibular schwannoma. In a retrospective observational study, 19 out of 338 (8%) enrolled adult patients demonstrated a TCR during transsphenoidal/transcranial surgery for pituitary adenomas. The 2 subgroups (TCR vs non-TCR) had similar patient's characteristics, risk factors, and histology. Preoperatively, there was a similar distribution of normal pituitary function in the TCR and non-TCR subgroups. In this TCR subgroup, there was a significant decrease of that normal pituitary function after operation (37%) compared to the non-TCR group (60%) (P < 0.03). The TCR subgroup therefore demonstrated a 3.15 times (95%CI 1.15-8.68) higher risk for non-normalizing of postoperative pituitary function compared with the non-TCR subgroup (P < 0.03). It is presented, for the first time, an impact of TCR on the functional hormonal outcome after pituitary surgery and strongly underline again the importance of the TCR in clinical daily practice. As a consequence, TCR should be considered as a negative prognostic factor of hormonal normalization after surgery for pituitary adenomas that should be included into routine practice.

Trigeminocardiac reflex during cerebellopontine angle surgery: anatomical location as a new risk factor

ABSTRACT 

Aim: Trigeminocardicac reflex (TCR), a brainstem reflex, can be manifested in almost all types of surgery in the head and neck region. Patients & methods: Retrospective review of 125 patients operated on cerebellopontine angle (CPA) tumors according to strict inclusion/exclusion criteria. Results: A total of 14 out of 125 patients showed TCR during CPA tumor operation. In total, 29% of those patients presented with a meningioma located exclusively premeatal, but not retromeatal in the CPA. There was significant relationship between meningiomas subgroups and TCR (Barnard test; p < 0.05). Conclusion: Anatomical location may represent an important, but not yet described risk factor for the TCR having therefore an important role in the understanding of the TCR.

The oculocardiac reflex may mimic signs of intracranial hypertension in patients with combined cerebral and ocular trauma

BACKGROUND

In the setting of head trauma, progressive bradycardia may raise suspicion for intracranial hypertension, especially when accompanied by pupillary abnormalities or systemic hypertension.

METHODS

We describe the case of a patient with concomitant cerebral and ocular trauma who presented with a fixed and dilated pupil and progressive bradycardia due to an oculocardiac reflex.

RESULTS

The oculocardiac reflex is an unusual cause of bradycardia due to stimulation of the ophthalmic division of the trigeminal nerve and has been described in a variety of clinical settings.

CONCLUSIONS

Clinicians should be aware that the oculocardiac reflex might mimic signs of intracranial hypertension in patients with combined facial and cerebral trauma.

Trigeminocardiac reflex in a child during pre-Onyx DMSO injection for juvenile nasopharyngeal angiofibroma embolization. A case report

We describe the occurrence of the trigeminocardiac reflex (TCR) during DMSO pre-flushing of the microcatheter in preparation for Onyx embolization via the internal maxillary artery. TCR has not been previously associated with embolization of extradural entities. Familiarity with this clinical reflex and its proper management may help in planning neurointerventional procedures involving DMSO injection in the trigeminal territory.

Oxygen-conserving reflexes of the brain: the current molecular knowledge

The trigemino-cardiac reflex (TCR) may be classified as a sub-phenomenon in the group of the so-called 'oxygen-conserving reflexes'. Within seconds after the initiation of such a reflex, there is neither a powerful and differentiated activation of the sympathetic system with subsequent elevation in regional cerebral blood flow (CBF) with no changes in the cerebral metabolic rate of oxygen (CMRO(2)) or in the cerebral metabolic rate of glucose (CMRglc). Such an increase in regional CBF without a change of CMRO(2) or CMRglc provides the brain with oxygen rapidly and efficiently and gives substantial evidence that the TCR is an oxygen-conserving reflex. This system, which mediates reflex protection projects via currently undefined pathways from the rostral ventrolateral medulla oblongata to the upper brainstem and/or thalamus which finally engage a small population of neurons in the cortex. This cortical centre appears to be dedicated to reflexively transduce a neuronal signal into cerebral vasodilatation and synchronization of electrocortical activity. Sympathetic excitation is mediated by cortical-spinal projection to spinal pre-ganglionic sympathetic neurons whereas bradycardia is mediated via projections to cardiovagal motor medullary neurons. The integrated reflex response serves to redistribute blood from viscera to brain in response to a challenge to cerebral metabolism, but seems also to initiate a preconditioning mechanism. Better and more detailed knowledge of the cascades, transmitters and molecules engaged in such endogenous (neuro) protection may provide new insights into novel therapeutic options for a range of disorders characterized by neuronal death and into cortical organization of the brain.