Abstract
Unintentional mechanical manipulation anywhere in the distribution of the trigeminal nerve might activate a reflexive bradycardia. Neurosurgeons need to bear in mind detrimental consequences on cardiac function. A female patient (53 years) underwent a computer-assisted (CAS), paranasal sinus operation performed under general anesthesia. During left sided CAS and preparation of the sinus ethmoidalis, heart rate significantly fell from 68 to 32 /min, while systolic arterial blood pressure decreased from 105 to 75 mmHg. Continuation of the preparation again decreased heart rate progressing to transient asystole lasting for 15 s. After removal of the instruments, asystole terminated without medical support. As heart rate decreased after renewed insertion of the CAS probe, sinus ethmoidalis surgery was completed after atropine administration. During neurosurgical procedures, the incidence of the reflex varies between 10 and 18%. To the best of our knowledge, we report for the first time on a direct stimulation of the ethmoidal nerve with instruments (CAS probe) during paranasal surgery. Although normally cardioprotective, exaggeration of the diving reflex can be detrimental and has been implicated in cardiorespiratory disorders, including sudden death and the sudden infant death syndrome.
1
Introduction
Many studies confirm that apnea and facial immersion induce diving bradycardia in humans . It is well established, in addition, that the diving response is mediated via the trigeminal nerve . More precisely, the ethmoidal nerve – an afferent vagal branch of the trigeminal nerve – induces diving bradycardia , as nicely substantiated by retrograde migration of herpes simplex viruses in muskrats .
Electrical stimulation within discrete sites of the spinal trigeminal complex in anesthetized or decerebrated rabbits induced bradycardia , and electrical stimulation of the anterior ethmoidal nerve in muskrats produced the diving response . Similarly, surgery in the cerebellopontine angle and transsphenoidal surgery for pituitary adenomas reduced heart rate, and the trigeminocardiac reflex complicates awake-craniotomy Prabhu et al. . Thus, in humans, mechanical stimulation anywhere in the distribution of the trigeminal nerve might activate a reflexive bradycardia. During neurosurgical procedures, the incidence of the reflex varies between 10 and 18% .
Here, mechanical stimulation during paranasal surgery was not only associated with pronounced bradycardia but also with transient cardiac arrest.
2
Patient and method
A female patient (53 years) underwent a computer-assisted (CAS), paranasal sinus operation performed under general anesthesia at the Evangelisches Krankenhaus Düsseldorf (DE). The patient was in good general condition and had good physical abilities. She was not under chronic medication and had no known cardiovascular diseases.
Propofol, fentanyl and cisatracurium were used for anesthetic induction. Endotracheal intubation, gastric intubation and throat tamponade were performed after anesthetic induction. Anesthesia was maintained using constant perfusion with remifentanyl plus a volatile anesthetic (isofloran; end-tidal vol. 0.7%). During anesthetic induction, a discreet hypotension was noticed.
Computer-aided surgery permits exact positioning of medical instruments by using CT imaging in two planes. During left sided surgery and preparation of the sinus maxillaris and frontalis, no cardiovascular irregularities were noticed. During preparation of the sinus ethmoidalis, heart rate significantly fell from 68 to 32/min, while systolic arterial blood pressure decreased from 105 to 75 mmHg. Continuation of the preparation again decreased heart rate progressing to transient asystole lasting for 15 s. After removal of the instruments, asystole terminated without medical support. As heart rate decreased after renewed insertion of the CAS probe, sinus ethmoidalis surgery was completed after atropine administration. No irregular vital function was noticed during right sided surgery.
2
Patient and method
A female patient (53 years) underwent a computer-assisted (CAS), paranasal sinus operation performed under general anesthesia at the Evangelisches Krankenhaus Düsseldorf (DE). The patient was in good general condition and had good physical abilities. She was not under chronic medication and had no known cardiovascular diseases.
Propofol, fentanyl and cisatracurium were used for anesthetic induction. Endotracheal intubation, gastric intubation and throat tamponade were performed after anesthetic induction. Anesthesia was maintained using constant perfusion with remifentanyl plus a volatile anesthetic (isofloran; end-tidal vol. 0.7%). During anesthetic induction, a discreet hypotension was noticed.
Computer-aided surgery permits exact positioning of medical instruments by using CT imaging in two planes. During left sided surgery and preparation of the sinus maxillaris and frontalis, no cardiovascular irregularities were noticed. During preparation of the sinus ethmoidalis, heart rate significantly fell from 68 to 32/min, while systolic arterial blood pressure decreased from 105 to 75 mmHg. Continuation of the preparation again decreased heart rate progressing to transient asystole lasting for 15 s. After removal of the instruments, asystole terminated without medical support. As heart rate decreased after renewed insertion of the CAS probe, sinus ethmoidalis surgery was completed after atropine administration. No irregular vital function was noticed during right sided surgery.
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