Trigeminocardiac reflex during surgery in the cerebellopontine angle

Abstract

<jats:p>In different experimental studies authors have analyzed the autonomic responses elicited by the electrical, mechanical, or chemical stimulation of the trigeminal nerve system. The trigeminocardiac reflex (TCR) is a well-recognized phenomenon that consists of bradycardia, arterial hypotension, apnea, and gastric hypermotility. It occurs during ocular surgery and during other manipulations in and around the orbit. Thus far, it has not been shown that central stimulation of the trigeminal nerve can also cause this reflex.</jats:p> <jats:p>The TCR was defined as clinical hypotension with a drop in mean arterial blood pressure (MABP) of more than 20% and bradycardia lower than 60 beats/minute. Pre-, intra-, and postoperative heart rate (HR) and blood pressure were reviewed retrospectively in 125 patients who underwent surgery for tumors of the cerebellopontine angle (CPA), and they were divided into a TCR group and a non-TCR group. Of the 125 patients, 14 (11%) showed evidence of TCR during dissection of the tumor near the trigeminal nerve at the brainstem. Their HR fell 38% and their MABP fell 48% during operative procedures as compared with preoperative levels. After cessation of manipulation, the HR and the MABP returned to preoperative levels. Risk factors for the occurrence of TCR were compared with results from the literature.</jats:p> <jats:p>The authors' results show the possibility of occurrence of a TCR during manipulation of the central part of the trigeminal nerve when performing surgery in the CPA.</jats:p>

The Oculocardiac Reflex may Mimic Signs of Intracranial Hypertension in Patients with Combined Cerebral and Ocular Trauma

“…Stimulation of any of the sensory branches of the trigeminal nerves may result in bradycardia, hypotension, apnea, or gastric hypermotility. This constellation of signs, the trigeminocardiac reflex, has been observed during procedures that involve direct or indirect manipulation of the fifth cranial nerve, including craniofacial surgery, dental procedures, resection of cerebellopontine angle tumors, rhizotomy of the trigeminal ganglion or sensory root, endoscopic transphenoidal surgery, and endovascular embolization of intracranial dural arteriovenous fistulae [11][12][13][14][15][16]. Case reports describe sudden intra-operative cardiac arrest (asystole) attributable to the trigeminocardiac reflex [17,18].…”

The Trigeminal Nerve

“…25 At present, the TCR is defined as involving a decrease in HR and a mean arterial blood pressure (MABP) of at least 20% of the baseline upon surgical manipulation at or around any sensory branch of the trigeminal nerve. [1][2][3]7,24 However, this definition may not able to detect subtle TCR episodes and therefore is likely to underestimate the true incidence of the reflex. 8 Still, such a definition would at least detect major events and thus should be used for clinical studies.…”

“…The reflex pathway activates cardioinhibitory parasympathetic vagal neurons, which terminate in the myocardium and which, when activated, cause negative chronotropic and inotropic responses. [1][2][3]5,7,24,25,50 (Figure 2.4). Consequently, the clinical features of the TCR range from the sudden onset of sinus bradycardia, bradycardia terminating in asystole, asystole with no preceding bradycardia, arterial hypotension, apnea, and gastric hypermotility.…”

“…Consequently, the clinical features of the TCR range from the sudden onset of sinus bradycardia, bradycardia terminating in asystole, asystole with no preceding bradycardia, arterial hypotension, apnea, and gastric hypermotility. [1][2][3]5,7,24,25,50 This reflex arch is considered to be intrinsic to the brain stem, as it can be elicited in decerebrate animals as well. 2,5,51 Experimental data further suggest that the TCR response is initially mediated from the spinal trigeminal complex and two of its caudal nuclear subdivisions: the nuclei caudalis and interpolaris.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Initial animal experiments (with rabbits and cats) on the TCR were conducted by Kratschmer et al, 15,16 who demonstrated occurrences of the TCR during the manipulation of nasal mucosa. Thereafter, beginning in the early twentieth century, this unique reflex gained much clinical attention in the form of the oculocardiac reflex (OCR), which is the negative cardiac response (mainly bradycardia) associated with the observed stimulation of the ophthalmic division of the trigeminal nerve during various ocular surgeries.…”