Effects of Two Different Anesthesia-analgesia Methods on the Incidence of Postoperative Delirium: a Multicenter, Randomized Controlled Trial

Brief Summary

Detailed Description

Delirium is an acutely occurred and transient mental syndrome characterized by global impairment of cognitive functions, reduced level of consciousness, abnormalities of attention, increased or decreased psychomotor activity, and disordered sleep-wake cycle. Postoperative delirium is a common complication in elderly patients after surgery. Dyer et al reviewed 80 primary studies and found that the mean incidence of postoperative delirium is about 36.8% (range 0%-73.5%) after surgery. It occurs in up to 80% of patients in the intensive care unit (ICU). Our recent studies found that delirium occurred in 51.0% of patients after cardiac surgery and in 44.5% of patients after non-cardiac surgery. The occurrence of postoperative delirium is associated with worse outcomes. Studies showed that delirious patients have prolonged ICU stay, increased incidence of complications, prolonged hospitalization, high mortality rate, and increased health care costs. Delirium is also associated with increased risk of long-term cognitive decline and poor quality of life. A recent follow-up study (mean follow-up time 27.9 ± 3.1 months) by our research group found that, after adjusting factors such as age, occurrence of postoperative complications, and stage of cancer, etc, the occurrence of postoperative delirium still remained an independent predictor of long-term mortality. The pathophysiology of delirium remains poorly understood. An universal phenomenon is that delirium frequently occurs in elderly patients after major complicated surgery, but is rarely seen after minor ambulatory surgery (such as cataract surgery). Studies also found that postoperative pain is an independent risk factor of delirium, whereas effective pain relief may help to reduce the incidence of delirium. Our recent studies showed that high serum cortisol level is an independent risk factor of postoperative delirium. In addition, inflammatory response may also contribute to the pathogenesis of delirium. Trauma, pain, cortisol secretion and inflammation are all important components of surgical stress response. The above results indicated that stress response produced by surgery might have an important role in the pathogenesis of delirium. Previous studies demonstrated that, when compared with general anesthesia, neuraxial anesthesia attenuates the hypersecretion of cortisol, and decreases the intensity of inflammatory response more effectively after surgery. And epidural analgesia provides better postoperative pain relief than intravenous analgesia. It was also reported that, when compared with general anesthesia and intravenous analgesia, neuraxial anesthesia and analgesia reduces the occurrence of postoperative complications and mortality in high risk patients. Combined epidural-general anesthesia is frequently used in clinical practice, and is performed in about 1/4 of patients undergoing surgery in the applicant's hospital. Theoretically, this anesthetic method provides advantages of both epidural and general anesthesia, i.e. it blocks the afferent pathway of nociceptive stimulus by neuraxial blockade during and after surgery, and allow patients to endure long-duration complicated surgeries without any awareness. However, there is no evidence whether combined epidural-general anesthesia/postoperative epidural analgesia can decrease the incidence of postoperative delirium in elderly patients undergoing major surgery. The objective of the study is to compare the effects of combined epidural-general anesthesia/postoperative epidural analgesia and general anesthesia/postoperative intravenous analgesia on the incidence of postoperative delirium in elderly patients undergoing major noncardiac surgery.

Primary Outcomes

Secondary Outcomes

• Intensive care unit (ICU) admission after surgery(During the day of surgery.)
• APACHE II score at ICU admission(Within 24 hours after surgery.)
• The percentage of ICU admission with endotracheal intubation(During the day of surgery.)
• The duration of Mechanical Ventilation in ICU(Up to 30 days after surgery.)
• The Length of ICU stay(Up to 30 days after surgery.)
• Time to the first onset of delirium(Up to 7 days after surgery.)
• Time to fluid/food intake(Up to 30 days after surgery.)
• Length of stay in hospital after surgery(Up to 30 days after surgery.)
• All-cause 30-day mortality(Within the first 30 days after surgery.)
• Non-delirium complications within 30 days after surgery surgery(Within the first 30 days after surgery.)
• The intensity of postoperative pain(During the first 3 postoperative days.)