Transcutaneous Auricular Vagus Nerve Stimulation and Quality of Recovery After Major Noncardiac Surgery

"Transcutaneous auricular vagus nerve stimulation is performed using earphone-shaped stimulators (tVNS501, Ruishenan Medical Device, Inc. JiangSu, China) on the left tragus areas of the outer ear for a total of 30 min. Using parameters we have identified through systematic review, electrical stimulation (pulse width: 200-300 μs; frequency: 25 Hz; duty cycles: 50%) is initiated at 200% perceptual threshold (PT) which means the minimum amount of electricity required to perceive electrical stimulation on the skin described as a pricking or tingling sensation. All conscious patients will be told they may or may not feel any sensation from the stimulation.~The stimulation will be performed between 15:00 and 17:00 on the first day before surgery, at least 30 minutes before the start of surgery and between 08:00 and 10:00 on the first to third day after surgery."

Sham stimulation is performed using earphone-shaped stimulators (tVNS501, Ruishenan Medical Device, Inc. JiangSu, China) on the left tragus areas of the outer ear for a total of 30 min. Using parameters we have identified through systematic review, electrical stimulation (pulse width: 200-300 μs; frequency: 25 Hz; duty cycles: 50%) is initiated at 200% perceptual threshold (PT) which means the minimum amount of electricity required to perceive electrical stimulation on the skin described as a pricking or tingling sensation. And the current will be automatically switched off after 15 s. All conscious patients will be told they may or may not feel any sensation from the stimulation. The stimulation will be performed between 15:00 and 17:00 on the first day before surgery, at least 30 minutes before the start of surgery and between 08:00 and 10:00 on the first to third day after surgery.