Related Experiment Video
Updated: Feb 14, 2026

The Muscle Cuff Regenerative Peripheral Nerve Interface for the Amplification of Intact Peripheral Nerve Signals
Published on: January 13, 2022
Effective dose of dexmedetomidine as an adjuvant sedative to peripheral nerve blockade in elderly patients
1Department of Surgery and Anaesthesiology Centre, PLA General Hospital, Beijing, China.
Background:
The median effective dose (ED50 ) of sedative dexmedetomidine adjuvant to peripheral nerve block (PNB) has not yet been verified in elderly patients. This study assessed the ED50 of intravenous dexmedetomidine for sedation in elderly patients who were undergoing total knee arthroplasty (TKA) with PNB.
Methods:
Forty-two patients aged 65-85 years were included and stratified into two groups according to age: young-old group (aged 65-74 years) and middle-old group (aged 75-85 years). After the PNB was performed, a pre-calculated dose of dexmedetomidine was administered for 10 min. The Observer's Assessment of Alertness/Sedation scale, bispectral index score, blood pressure and heart rate were recorded. ED50 values of dexmedetomidine for adequate sedation were estimated by the up-and-down method of Dixon and probit regression.
Results:
The ED50 of single-dose dexmedetomidine adjuvant to PNB was 0.57 μg/kg (95% confidence interval [CI], 0.47-0.65) in the young-old group and 0.38 μg/kg (95% CI, 0.28-0.46) in the middle-old group. The ED50 of dexmedetomidine differed significantly between the two groups (P < 0.001). In addition, no significant adverse hemodynamic or hypoxemic effects were noted.
Conclusion:
We determined the ED50 for sedation using intravenous dexmedetomidine adjuvant to PNB in elderly patients. The ED50 of dexmedetomidine in the middle-old group decreased by 33% compared with that in the young-old group with a mean age difference of 11 years between the two groups.
Related Concept Videos
Drug Dosing: Geriatric Patients
Drug Dosing: Obese Patients
Peripheral Nervous System: Ganglia and Nerves
Nerves
The nerve is a bundle of axons that serves as the communication highway in the PNS. Each nerve is ensheathed in a protective layer of connective tissue called the epineurium. This outermost layer safeguards the nerve and supports the...
Insulin: Dosing Regimen and Adverse Effects
The basal dose constitutes about 40%-50% of the total daily dose, with the rest as premeal insulin. The mealtime insulin dose should mirror...
Neuromuscular Junction And Blockade
Pharmacodynamics in Geriatric Patients: Effects of Age

