Anesth Analg 2006;102:1910
© 2006 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000215147.73461.A9
LETTER TO THE EDITOR
From the Anesthesiologist's Perspective: Placement of Vagal Nerve Stimulator
Arzu Gerçek, MD, and
M. Memet özek, MD
Section of Neuroanesthesiology and Reanimation; agercek{at}hotmail.com (Gerçek)
Division of Pediatric Neurosurgery; Marmara University; Institute of Neurological Science; Istanbul, Turkey (özek)
To the Editor:
Despite recent pharmacological advances in the treatment of epilepsy, approximately 30%–40% of epileptic patients continue to have intractable seizures. Nearly half of these are partial onset seizures (1,2). Vagal nerve stimulation is a new nonpharmacological, nondestructive therapy for patients with refractory epilepsy. The Neuro Cybernetic Prosthesis vagal nerve stimulator has been available since 1997. This device delivers intermittent electrical stimulation to the left cervical vagal nerve trunk, which transmits rostral impulses that have widespread effects on neuronal excitability throughout the central nervous system. This intermittent excitation renders vulnerable neurons unresponsive to epileptic propagation.
The pulse generator is surgically placed in a subcutaneous pocket in the left pectoral area. Electrodes are wrapped around the left vagal nerve and are connected to the pulse generator via subcutaneous tunnel. The stimulation period and power are calibrated and the system starts working in the immediate postoperative period (2–4).
The vagus nerve serves many critical functions. Stimulation of the parasympathetic branch results in cardiac arrhythmias, while stimulation of the motor branch causes hoarseness, cough, dyspnea, nausea, and vomiting (2,5). The vagal nerve stimulator brochure warns of possible cardiac arrest. We decided to analyze the perioperative period of placement from the anesthesiologist's perspective.
We studied the perioperative sequelae of vagal nerve stimulator placement in 11 patients (7 male/4 female, mean age 21.2 ± 13.1 yr) with intractable epilepsy after obtaining IRB approval and patients' informed consent. Patients were not premedicated. Anesthesia was induced with IV propofol 2 mg/kg, remifentanil 1 µg/kg, and vecuronium bromide 0.1 mg/kg. After tracheal intubation, anesthesia was maintained with remifentanil infusion 0.25 µg · kg–1 · min–1 and 66% N2O in O2 and 0.5% isoflurane. Heart rate, noninvasive arterial blood pressure, Spo2, and end-tidal CO2 were monitored and recorded at 5-min intervals. Any rhythm rather than sinus was noted. Patients were followed in the Neuro Intensive Care Unit for 24 h after surgery.
The duration of surgery was 111.3 ± 27.3 min. Intraoperatively, only one patient experienced bradycardia (35 bpm) at the time of the vagal stimulation test. The heart rate returned to normal (75 bpm) without intervention. During the 24 h of observation after surgery, no patient had hoarseness, cough, dyspnea, nausea, vomiting, and any rhythm rather than sinus.
Our limited experience with 11 patients suggests that vagal nerve stimulator placement is well tolerated.
References
- Amar AP, Christi NH, Levy ML, et al. An institutional experience with cervical vagus nerve trunk stimulation for medically refractory epilepsy: rationale, technique and outcome. Neurosurgery 1998;43:1265–80.[Web of Science][Medline]
- Labar D, Nikolov B, Tarver B, Erase R. Vagus nerve stimulation for symptomatic generalized epilepsy. Epilepsia 1998;39:201–5.[Web of Science][Medline]
- Kirse DJ, Werle AH, Murphy JV, et al. Vagus nerve stimulator implantation in child. Arch Otolaryngol Head Neck Surg 2002;128:1263–8.[Abstract/Free Full Text]
- Bernard EJ, Passannante AN, Mann B, et al. Insertion of vagal nerve stimulator using local and regional anesthesia. Surg Neurol 2002;57:94–8.[Medline]
- Kahle W, Leonhardt H, Platzer W. Color atlas and textbook of human anatomy, volume 3. New York: Thieme, 1986.
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