Dexmedetomidine Combined With Ropivacaine for Postoperative Continuous Femoral Nerve Block

Study Overview
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Brief Summary
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Delirium is common in the elderly after orthopedic surgery and is associated with worse outcomes. Continuous femoral nerve block is frequently used for postoperative analgesia after total knee arthoplasty. The investigators hypothesize that dexmedetomidine, when combined with ropivacaine for continuous femoral nerve block, can reduce the incidence of delirium and improve the long-term outcome in elderly patients after total knee arthroplasty.

Detailed Description
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A growing number of elderly patients undergo total knee arthroplasty. 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. Dexmedetomidine has been shown to prolong the duration of nerve block without neurotoxicity and improve postoperative sleep quality. The investigators hypothesize that dexmedetomidine, when combined with ropivacaine for continuous femoral nerve block, can reduce the incidence of delirium and improve the long-term outcome in elderly patients after total knee arthroplasty.

Official Title
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Impact of Dexmedetomidine Combined With Ropivacaine for Postoperative Continuous Femoral Nerve Block on Postoperative Delirium and Long-term Oucomes in Elderly Patients After Single Knee Arthroplasty

Conditions
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Elderly, Knee Arthroplasty, Nerve Block, Dexmedetomidine, Postoperative Delirium, Long-term Outcome

Intervention / Treatment
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* Drug: Dexmedetomidine
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Elderly patients (≥ 65 years but < 90 years); Scheduled to undergo single total knee arthroplasty; Planned to receive continuous femoral nerve block for postoperative analgesia. 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 hemorrhagic disease or coagulopathy (platelet count, prothrombin time and/or activated partial thrombin time below the lower limit of normal); Preoperative obstructive sleep apnea (diagnosed as obstructive sleep apnea, or STOP-Bang score ≥3); Preoperative 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); ASA classification ≥ IV or unlikely to survive for more than 24 hours after surgery.

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dexmedetomidine group<br>For patients in the dexmedetomidine group, postoperative analgesia is provided in the form of continuous femoral nerve block. The formula contains a mixture of 0.2% ropivacaine 250 ml and 3.75 ug/kg dexmedetomidine. The analgesic pump is set to administer a continuous infusion at a rate of 5 ml/h for 48 hours (equivalent to dexmedetomidine infusion at a rate of 0.075 ug/kg/h). | Drug: Dexmedetomidine<br>* Patients in this group receive continuous femoral nerve block analgesia for 48 hours after surgery. The formula is a mixture of 0.2% ropivacaine 250ml and 3.75 ug/kg dexmedetomidine. The analgesic pump is set to administer a continuous infusion at a rate of 5 ml/h (equivalent to a dexmedetomidine infusion at a rate of 0.075 ug/kg/h).<br>* Other names: Continuous femoral nerve block with ropivacaine;|
| Placebo Comparator: Control group<br>For patients in the control group, postoperative analgesia is provided in the form of continuous femoral nerve block. The formula contains a mixture of 0.2% ropivacaine 250 ml and placebo (normal saline). The analgesic pump is set to administer a continuous infusion at a rate of 5 ml/h for 48 hours. | Drug: Placebo<br>* Patients in this group receive continuous femoral nerve block analgesia for 48 hours after surgery. The formula is a mixture of 0.2% ropivacaine 250 ml and placebo. The analgesic pump is set to administer a continuous infusion at a rate of 5 ml/h.<br>* Other names: Continuous femoral nerve block with ropivacaine;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of delirium during the first 3 days after surgery | Incidence of delirium during the first 3 days after surgery | The first 3 days after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Daily prevalence of delirium during postoperative days 1-3 | Daily prevalence of delirium during postoperative days 1-3 | The first 3 days after surgery | 
| Length of stay in hospital after surgery | Length of stay in hospital after surgery | Up to 30 days after surgery | 
| Incidence of non-delirium complications within 30 days after surgery | Incidence of non-delirium complications within 30 days after surgery | Up to 30 days after surgery | 
| All-cause 30-day mortality | All-cause 30-day mortality | At 30 days after surgery | 
| Quality of life at 30 days after surgery | Quality of life at 30 days after surgery is assessed with the 12-items Short Form Health Survey (SF-12), a 12-item questionnaire that provides assessments of physical and mental health-related quality of life. The score ranges from 12 to 48, with higher score indicating better function. | At 30 days after surgery | 
| Cognitive function at 30 days after surgery | Cognitive function at 30 days after surgery is assessed with modified Telephone Interview for Cognitive Status (TICS-m), a 12-item questionnaire that provides an assessment of global cognitive function by verbal communication via telephone. The score ranges from 0 to 50, with higher score indicating better function. | At 30 days after surgery | 
| Overall survival within 3 years after surgery | Overall survival within 3 years after surgery | Up to 3 years after surgery | 
| Survival rates at the end of the 1st，2nd, and 3rd years after surgery | Survival rates at the end of the 1st，2nd, and 3rd years after surgery | At the end of the 1st, 2nd, and 3rd years after surgery | 
| Incidence of new-onset diseases within 3 years after surgery | Incidence of new-onset diseases within 3 years after surgery | Up to 3 years after surgery | 
| Quality of life at the end of the 1st, 2nd, and 3rd years after surgery: SF-12 | Quality of life at the end of the 1st, 2nd, and 3rd years after surgery is assessed with the 12-items Short Form Health Survey (SF-12), a 12-item questionnaire that provides assessments of physical and mental health-related quality of life. The score ranges from 12 to 48, with higher score indicating better function. | At the end of the 1st, 2nd, and 3rd years after surgery | 
| Cognitive function at the end of the 1st, 2nd, and 3rd years after surgery | Cognitive function at the end of the 1st, 2nd, and 3rd years after surgery is assessed with modified Telephone Interview for Cognitive Status (TICS-m), a 12-item questionnaire that provides an assessment of global cognitive function by verbal communication via telephone. The score ranges from 0 to 50, with higher score indicating better function. | At the end of the 1st, 2nd, and 3rd years after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Elderly, Knee Arthroplasty, Nerve Block, Dexmedetomidine, Postoperative Delirium, Long-term Outcome