Transcutaneous vagus nerve stimulation may attenuate postoperative cognitive dysfunction in elderly patients.

Postoperative cognitive dysfunction (POCD) is a decline in cognitive function for weeks or months after surgery. It may affect the patients' length of hospital stay, quality of life, the rehabilitation process, and work performance. Prolonged POCD occurs frequently after cardiac surgery, and the risk of POCD increases with age. The pathophysiology of POCD has not been well understood. However, emerging evidences indicate that various inflammatory mediators are involved in the pathophysiology of POCD and inflammatory response may a potential pathogenic factor. The vagus nerve stimulation has been shown to decrease production and release of pro-inflammatory cytokines through the cholinergic anti-inflammatory pathway (CAP) in both animal model and human. Considering that the inflammation plays a definite role in the pathogenesis of POCD and the vagus nerve can mediate inflammation via CAP, we hypothesize that the transcutaneous vagus nerve stimulation may attenuate POCD by decreasing inflammatory response in elderly patients.