Anesth Pain Med.  2017 Oct;12(4):320-325. 10.17085/apm.2017.12.4.320.

Comparison of several dosing schedules of intravenous dexmedetomidine in elderly patients under spinal anesthesia

• Yeom JH
• Ahn DW
• Kim KH

• KMID: 2405848
• DOI: http://doi.org/10.17085/apm.2017.12.4.320

Abstract

BACKGROUND
Many clinicians have probably used subjective, unscientific methods for dose reduction to avoid overdose in elderly patients. The aim of this study was to compare several dosing schedules of intravenous dexmedetomidine (DEX) to identify the appropriate dosing schedule within the therapeutic dose range for adequate sedation of elderly patients under spinal anesthesia.
METHODS
After administration of spinal anesthesia, a loading dose of DEX was injected over 10 min in three groups with the following dosages: group A, 1.0 μg/kg of actual body weight; group B, 1.0 μg/kg of ideal body weight (IBW); and group C, 0.8 μg/kg of IBW. Then, a maintenance infusion (0.5 μg/kg of each BW/h) was administered. The bispectral index score (BIS), the time required to reach BIS 80, airway obstruction score, and the occurrence of bradycardia were recorded.
RESULTS
The changes in the BIS among the groups over time were found to have statistically significant differences (P < 0.001). The times required to reach BIS 80 were 6.1 ± 5.3 min, 5.0 ± 3.6 min, and 11.0 ± 8.6 min in groups A, B, and C, respectively (P < 0.001). The airway obstruction score and the frequency of bradycardia did not have statistically significant differences among the groups.
CONCLUSIONS
An initial loading dose of DEX that is 0.8 μg/kg of IBW over 10 min, followed by an infusion rate of less than 0.5 μg/kg of IBW/h may be adequate for sedation in elderly patients receiving spinal anesthesia.

Keyword

Dexmedetomidine; Ideal body weight; Sedation; Spinal anesthesia

MeSH Terms

Aged*
Airway Obstruction
Anesthesia, Spinal*
Appointments and Schedules*
Body Weight
Bradycardia
Dexmedetomidine*
Humans
Ideal Body Weight
Dexmedetomidine

Figure

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  Fig. 1 CONSORT diagram.

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  Fig. 2 Bispectral index score. Circle represents group A (loading dose of dexmedetomidine: 1 μg/kg of actual body weight). Square represents group B (loading dose of dexmedetomidine: 1 μg/kg of ideal body weight). Triangle represents group C (loading dose of dexmedetomidine: 0.8 μg/kg of ideal body weight). After administration of the loading dose in all groups, a maintenance dose of 0.5 μg/kg of ideal or actual body weight/h was administered. Data represents mean — SD in groups A and B, and mean + SD in group C. Group A vs. B, P = 0.490; group A vs. C, P = 0.001; group B vs. C, P = 0.026.

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