Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) occur in 11-51% of patients after surgery, and its prevalence increases with age. The occurrence of delirium is associated with increased morbidity and mortality, prolonged hospital stay, worse functional recovery. Orthopedic procedures and specifically joint replacements have been considered as a major risk for development of chronic postsurgical pain (CPSP). Approximately 13-44% of patients will develop CPSP after knee or hip arthOpioid abuseroplasty. CPSP may cause the discomfort, distress, disability and opioid abuse. Mounting evidence has revealed that inflammation triggered by surgical trauma plays a key role in POD, POCD and CPSP. Recent studies found that vagus nerve stimulation showed the suppression of inflammation. In this study, the effect of perioperative transauricular vagus nerve stimulation on the prognosis of patients undergoing arthroplasty will be investigated, providing potential solutions for the prevention and treatment of postoperative cognitive dysfunction, postoperative delirium and chronic postsurgical pain.
The investigators assessed POD by the Confusion Assessment Method for the ICU twice daily for 7 days after surgery. Participants' cognitive function was assessed with neuropsychological battery tests. The tests included digit span (forward and backward), Corsi block, paired associate verbal learning, digit symbol test, trail-making test and so on.The investigators make a CPSP diagnosis based on the 11th revision of the International Classification of Diseases.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
600
The transaricular vagus nerve stimulator was placed in the left ear trunk, which is dominated only by the auricular branch of the vagus nerve. Continuous stimulation was performed at a frequency of 25Hz with pulse width of 300 μs. The stimulation was adjusted to be higher than the perception threshold and lower than the pain threshold. Each stimulation lasted for 30 minutes, three times per day (morning, noon, evening), from 1 day before surgery to 7 days after surgery, and the treatment lasted for 9 consecutive days.
The transaricular vagus nerve stimulator was placed in the same position as the experimental group, covered with an insulating film and placed at the site of the stimulation, so that the patient could not actually receive the electrical stimulation. Continuous stimulation was performed at a frequency of 25Hz and pulse width of 300 μs, and the stimulation was adjusted to be higher than the perception threshold and lower than the pain threshold. Each stimulation lasted for 30 minutes, three times per day (morning, noon, evening), from 1 day before surgery to 7 days after surgery, for 9 consecutive days.
Xuzhou Central Hospital
Changzhou, Jiangsu, China
Postoperative cognitive function
The incidence of POCD was compared between the experimental group and the control group.The preoperative and postoperative differences of the following scales were calculated and compared: Digit Span (forward and backward), Visual Retention and Paired Associate Verbal Learning subtests of the Wechsler Memory Scale, Digit Symbol subtest of the Wechsler Adult Intelligence ScaleRevised, Halstead-Reitan Trail Making Test (Part A), Corsi Block Test and Grooved Pegboard Test (favored and unfavored hand). The standard deviation (SD) for each test was computed from the preoperative scores. A participant whose postoperative performance declined by ≥1 SD as compared to each preoperative test score on ≥2 tests was classified as POCD.
Time frame: 1 month after the surgery.
Postoperative cognitive function
The incidence of POCD was compared between the experimental group and the control group.The preoperative and postoperative differences of the following scales were calculated and compared: Digit Span (forward and backward), Visual Retention and Paired Associate Verbal Learning subtests of the Wechsler Memory Scale, Digit Symbol subtest of the Wechsler Adult Intelligence ScaleRevised, Halstead-Reitan Trail Making Test (Part A), Corsi Block Test and Grooved Pegboard Test (favored and unfavored hand). The standard deviation (SD) for each test was computed from the preoperative scores. A participant whose postoperative performance declined by ≥1 SD as compared to each preoperative test score on ≥2 tests was classified as POCD.
Time frame: 3 months after the surgery.
Postoperative delirium
The incidence of POD was compared between the experimental group and the control group.Postoperative delirium was assessed by the Delirium Assessment Scale (CAM-ICU)
Time frame: Consecutive 7 days after the surgery
Acute postoperative pain
The incidence of acute postoperative pain was compared between the experimental group and the control group.Acute postoperative pain was assessed by Visual Analogue Scale(VAS) for 7 consecutive days within 1 week after surgery.
Time frame: Consecutive 7 days after the surgery for acute pain
Chronic Postsurgical pain
The incidence of chronic postoperative pain (CPSP) was assessed by the Short Form McGill Pain Questionnaire (SF-MPQ) and Neuropathic Pain Scale (NPS).The incidence of CPSP was compared between the experimental group and the control group.
Time frame: 3 months after the surgery for chronic pain
TNF-α level in peripheral venous blood
The incidence of TNF-α level (pg/ml) in peripheral venous blood was compared between the experimental group and the control group
Time frame: 1 day before the surgery, Postoperative day 1, 3, 5
IL-6 level in peripheral venous blood
The incidence of IL-6 level (pg/ml) in peripheral venous blood was compared between the experimental group and the control group
Time frame: 1 day before the surgery, Postoperative day 1, 3, 5
IL-1β level in peripheral venous blood
The incidence of IL-1β level (pg/ml) in peripheral venous blood was compared between the experimental group and the control group
Time frame: 1 day before the surgery, Postoperative day 1, 3, 5
cortisol level in peripheral venous blood
The incidence of cortisol level (μg/dL) in peripheral venous blood was compared between the experimental group and the control group
Time frame: 1 day before the surgery, Postoperative day 1, 3, 5
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