Improving the functionality of intraoperative nerve monitoring during thyroid surgery: is lidocaine an alternative?
Background. The role of intraoperative nerve monitoring (IONM) in thyroid surgery remains a controversial issue for surgeons regardless of their training and experience. This monitoring method is not intended to visualize the recurrent laryngeal nerve, but rather to assess its function intraoperati...
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| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
Zaslavsky O.Yu.
2025-05-01
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| Series: | Медицина неотложных состояний |
| Subjects: | |
| Online Access: | https://emergency.zaslavsky.com.ua/index.php/journal/article/view/1869 |
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| Summary: | Background. The role of intraoperative nerve monitoring (IONM) in thyroid surgery remains a controversial issue for surgeons regardless of their training and experience. This monitoring method is not intended to visualize the recurrent laryngeal nerve, but rather to assess its function intraoperatively and to help make a prognosis in patients who develop recurrent laryngeal nerve paralysis. Because of its simplicity and cost-effectiveness, electromyography recording of the vocal cords using surface electrodes integrated into or attached to the endotracheal tube is probably the most commonly used IONM method. Full functionality of IONM depends on near-complete laryngeal relaxation and reflex inhibition without the use of neuromuscular blocking agents. The depth of anesthesia required to meet these criteria often results in hemodynamic instability. During our study, we used intravenous lidocaine infusion, which allowed for good operating and monitoring conditions without significant hemodynamic fluctuations. The purpose of the study is to evaluate the effect of lidocaine administered intravenously in estimated doses on the IONM and laryngotracheal reflexes during surgical interventions on the thyroid and parathyroid glands. Materials and methods. Forty-six patients were randomly assigned to group 1 where lidocaine was administered and group 2 with no lidocaine was used. All patients were anesthetized with a narcotic analgesic and inhalation anesthetic. The loading dose of lidocaine was administered at the rate of
1 mg/kg intravenously, and the maintenance dose was calculated at 1.5 mg/kg/hour. For IONM, a Dragonfly single-channel laryngeal surface electrode (Electrode LSE 500Ms; Neurovision Medical Products, Ventura, CA, USA) attached to a cuffed endotracheal tube 7.0 (Medicare, China) was used during surgery according to the manufacturer’s instructions. Results. The number of patients who required stimulating current at 0.5 mA (the manufacturer’s recommended strength is 1.5 mA) was significantly higher in the lidocaine group (P = 0.001) than in the no lidocaine group (P = 0.00006). Similarly, the proportion of patients with < 50 % drop in aggregate impedance level at the end of surgery was significantly higher in group 1 than in group 2. In addition, the proportion of patients with hypotensive episodes and need to correct blood pressure with medications more than twice during surgery was significantly lower in group 1 than in group 2 (P < 0.05). Conclusions. Patients who were prescribed lidocaine intravenously were more resistant to laryngotracheal irritation during surgery, and this made it possible to maintain such a condition of the larynx, which was necessary to ensure its increased relaxation and suppression of reflexes when using IONM. Our ability to elicit a positive signal with stimulating current of 0.5 mA intraoperatively and provide a drop in aggregate impedance level < 50 % before the end of surgery was statistically significant in the intravenous lidocaine group. |
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| ISSN: | 2224-0586 2307-1230 |