Stimulation with submaximal current for train-of-four monitoring

Area of Science:

• Anesthesiology
• Neuromuscular Monitoring
• Clinical Pharmacology

Background:

• Train-of-four (TOF) stimulation is crucial for assessing neuromuscular blockade.
• Traditional supramaximal stimulation can cause discomfort in awake patients.
• Optimizing TOF stimulation parameters is needed for improved patient comfort and reliable data.

Purpose of the Study:

• To evaluate patient comfort with varying currents during TOF stimulation.
• To compare the reliability of T4/T1 ratio measurements using submaximal versus supramaximal stimuli.
• To determine if submaximal currents can be used for effective neuromuscular monitoring.

Main Methods:

• Healthy volunteers rated discomfort using a visual analog scale (VAS) at 20, 30, and 50 mA TOF stimulation.
• Neuromuscular responses (single twitch and TOF) were recorded via mechanogram in postoperative and intraoperative patients.
• T4/T1 ratios were calculated at 20, 30, and 50 mA to assess reliability.

Main Results:

• Median VAS scores for discomfort increased significantly with higher currents (2, 3, and 6 at 20, 30, 50 mA, respectively).
• Single twitch heights increased with higher currents, but T4/T1 ratios showed no statistical difference across tested currents.
• Mean T4/T1 ratios were consistent across 20, 30, and 50 mA (approx. 0.80).

Conclusions:

• Submaximal TOF stimulation is more comfortable for awake patients needing neuromuscular monitoring.
• T4/T1 ratio assessment is reliable using submaximal currents, both intraoperatively and postoperatively.
• This approach enhances patient comfort without compromising the accuracy of neuromuscular blockade assessment.