Diagnostic Feasibility of 100 Hz Tetanic Stimulation

The aim of the present study is to investigate the applicability of 100 Hz tetanic stimulation with an electromyography (EMG) device. The aim is to determine whether fatigue develops with 100 Hz tetanic stimulation in anaesthetized, non-relaxed patients with normal or abnormal baseline electroneurographic (ENG) findings. Electric responses of the musculus digiti minimi elicited by supramaximal stimulation of the ulnar nerve at the carpal tunnel are monitored. Alpine Biomed ENG-EMG device with Keypoint software version 5.11 is used for the examinations. The exposed arm is fixed on the armboard, the skin is degreased and then the electrodes for monitoring are mounted lege artis. After the anesthesia has been induced, ENG of the ulnar nerve is examined. Based on the results of the ENG test, patients are divided into separate groups (normal or abnormal ENG). During the ENG test, the supramaximal current is determined. Afterwards, repetitive tetanic stimulation of the defined frequency (60 and 100 Hz) and duration (5 sec) is applied to the two test groups at the current according to the test plan.

The clinical utilities of the study results are:

• Determination of the "safety margin" of neuromuscular junction, which is not provided by routine monitoring.
• To investigate how comorbid status (especially chronic conditions affecting peripheral nerves such as polyneuropathy) influences the feasibility of tetanic stimulation in the diagnostics of residual neuromuscular block and safety margin.

Inclusion criteria

• ASA 1-3;
• BMI 18.5-25 (normal body weight);
• patient is in supine position with one arm accessible.

Exclusion criteria

• diseases with impaired neuromuscular function (myopathies, severe liver and kidney failure);
• drugs affecting neuromuscular function (magnesium, aminoglycosides);
• pregnancy (pregnancy tests are carried out in women of childbearing age to rule out pregnancy);
• breast-feeding;
• acute surgery