Trigeminocardiac reflex

Abstract

The trigemino-cardiac reflex (TCR) is defined as the sudden onset of parasympathetic dysrhythmia, sympathetic hypotension, apnea or gastric hypermotility during stimulation of any of the sensory branches of the trigeminal nerve. The sensory nerve endings of the trigeminal nerve send neuronal signals via the Gasserian ganglion to the sensory nucleus of the trigeminal nerve, forming the afferent pathway of the reflex arc. This afferent pathway continues along the short internuncial nerve fibers in the reticular formatio to connect with the efferent pathway in the motor nucleus of the vagus nerve. Clinically, the trigemino-cardiac reflex has been reported to occur during craniofacial surgery, balloon-compression rhizolysis of the trigeminal ganglion, and tumor resection in the cerebellopontine angle. Apart from the few clinical reports, the physiological function of this brainstem-reflex has not yet been fully explored. From experimental findings, it may be suggested that the trigemino-cardiac reflex represents an expression of a central neurogenic reflex leading to rapid cerebrovascular vasodilatation generated from excitation of oxygen-sensitive neurons in the rostral ventrolateral medulla oblongata. By this physiological response, the adjustments of the systemic and cerebral circulations are initiated to divert blood to the brain or to increase blood flow within it. As it is generally accepted that the diving reflex and ischemic tolerance appear to involve at least partially similar physiological mechanisms, the existence of such endogenous neuroprotective strategies may extend the actually known clinical appearance of the TCR and include the prevention of other potentially brain injury states as well. This may be in line with the suggestion that the TCR is a physiological, but not a pathophysiological entity.

Peribulbar block or topical application of local anaesthesia combined for paediatric strabismus surgery

“…..................................................................................................................................................................................................................... reflex. The study also demonstrates the common problem of prophylaxis in the prevention of the intra-operative trigemino-cardiac reflex [2][3][4][5].…”

“…Consequently, we feel the comment 'The potential usefulness of this technique is much smaller (especially in strabismus surgery)', is misplaced, as the fact that peri-bulbar block reduced the incidence of the oculocardiac reflex to 13% in this high risk group, does underline its efficacy. Schaller et al themselves talk about the need for conduction block at the ciliary ganglion to bring down the incidence of oculocardiac reflex, referring to the work of Misurya et al [3].…”

Serotonergic Modulation of the Trigeminocardiac Reflex Neurotransmission to Cardiac Vagal Neurons in the Nucleus Ambiguus

“…The reflex responses evoked on stimulation of the trigeminal nerve have often been termed the "trigeminocardiac reflex" in the clinical literature and "trigeminal depressor responses" in the earliest animal studies of this reflex using the rabbit model (Kumada et al 1977(Kumada et al , 1978Schaller 2004Schaller , 2005Schaller , 2007Schaller and Buchfelder 2006;Schaller et al 1999). Trigeminal depressor responses can be evoked by electrical stimulation of the root entry of the trigeminal nerve as well as from many branches of the peripheral trigeminal nerve, including the supra-and infraorbital (Kumada et al 1977) as well as the ethmoidal nerve (McCulloch et al 1999).…”

Classification of Meningiomas in the Cerebellopontine Angle

“…Signifi cant decrease in heart rate (HR) and mean arterial blood pressure (MABP) occurs during tumor dissections near the trigeminal nerve at the brainstem (Arasho et al 2013 ;Schaller 2004 ;Schaller et al 1999bSchaller et al , 2009, also in CPA meningiomas (Schaller et al 1999b ). This phenomenon is called trigeminocardiac refl ex (Arasho et al 2013 ;Schaller 2004 ;Schaller et al 1999bSchaller et al , 2009 and is described in more detail earlier in this book series (Arasho et al 2013 ).…”