Dexmedetomidine Supplemented Intravenous Analgesia in Elderly After Orthopedic Surgery

Impact of Dexmedetomidine Supplemented Intravenous Analgesia on Postoperative Delirium and Long-term Outcomes in Elderly After Orthopedic Surgery: A Multicenter, Double-blinded, Randomized Controlled Trial

Delirium is common in the elderly after orthopedic surgery and is associated with worse outcomes. The investigators hypothesize that, for elderly patients after orthopedic surgery, dexmedetomidine supplemented intravenous analgesia can reduce the incidence of delirium and improve the long-term outcomes.

A growing number of elderly patients undergo orthopedic surgery each year. Delirium is a common complication in these patients after surgery and is associated with worse outcomes, including prolonged hospital stay, poor functional recovery, decreased cognitive function, increased health care costs, and elevated mortality rate. Previous studies showed that, for elderly patients admitted to the intensive care unit after non-cardiac surgery, low-dose dexmedetomidine infusion improved subjective sleep quality and reduced delirium early after surgery; it also increased survival up to 2 years and improved life quality in 3-year survivors. The investigators hypothesize that dexmedetomidine supplemented intravenous analgesia (in the form of patient-controlled analgesia) can also reduce delirium and improve long-term outcomes in elderly patients after orthopedic surgery.

Inclusion Criteria:

• Age ≥ 65 years but < 90 years;
• Scheduled to undergo total knee/hip replacement surgery, or spinal surgery;
• Planned to use patient-controlled intravenous analgesia (PCIA) after surgery.

Exclusion Criteria:

• Refuse to participate in this study;
• Preoperative history of schizophrenia, epilepsy, Parkinsonism, or myasthenia gravis;
• Inability to communicate in the preoperative period because of coma, profound dementia or language barrier;
• Preoperative obstructive sleep apnea (diagnosed sleep apnea syndrome or a STOP-Bang score ≥3 combined with a serum bicarbonate ≥28 mmol/L);
• Sick sinus syndrome, severe sinus bradycardia (< 50 beats per minute), or second-degree or above atrioventricular block without pacemaker;
• Severe hepatic dysfunction (Child-Pugh class C);
• Severe renal dysfunction (requirement of renal replacement therapy before surgery);
• American Society of Anesthesiologists physical status >IV, or estimated survival ≤24 h.