Intravenous Or Topical Lidocaine And Neuromonitoring in Thyroid Surgery (IOLANT Study)

The use of neuromonitoring in thyroid surgery imposes a number of special demands for anaesthetic management. Such demands include avoiding muscle relaxation and local anaesthesia. Maintaining a balance between the risk of awakening during surgery and excessively deep anaesthesia in fast track surgery is an important task for the anaesthesiologist.

Mild anaesthesia in the absence of muscle relaxation increases the risk of developing laryngeal reflexes, coughing during surgery, while excessively deep anaesthesia slows down recovery after surgery and increases the risk of arterial hypotension. The frequency and duration of arterial hypotension, as well as the depth of anesthesia assessed by the Bispectral index, are independent risk factors for postoperative cardiovascular complications and long-term mortality. On the other hand, coughing in response to irritation of the endotracheal tube during recovery from anesthesia is recognized as a risk factor for respiratory and cardiovascular complications, as well as postoperative wound insufficiency.

Optimization the anesthesia by intravenous infusion of lidocaine can improve anesthesia controllability, hemodynamic stability and overall anesthesia recovery rates. Local use of lidocaine, including filling the endotracheal tube cuff with its alkalinized solution, has also been shown to be effective in reducing the frequency of laryngeal reflexes upon awakening after surgery of varying duration. However, the efficacy and safety of local use of lidocaine under neuromonitoring conditions has not been studied. Despite recommendations to avoid the local use of lidocaine for tracheal intubation, there is evidence of the safety of this technique in the absence of a negative impact on the quality of neuromonitoring.

The purpose of this study is to test the hypothesis that the quality of recovery with topical lidocaine is better than placebo. At the same time, the investigators assume that recovery after surgery will be comparable with both local and intravenous use. Intergroup differences in arterial hypotension, depth of anesthesia and intraoperative neuromonitoring parameters will also be investigated.