[Effects of dexmedetomidine on sedation and β-endorphin in traumatic brain injury: a comparative study with propofol]

To compare the efficacy of dextraldexmede (DEX) and propofol on sedation and β-endorphin (β-EP) in patients with moderate and severe traumatic brain injury (TBI).

Ninety patients with moderate and severe TBI with Glasgow coma score (GCS) 6-13 were randomly divided into three groups according to the order of admission of odd and even numbers. In group A (DEX/+morphine), DEX load 0.5-1.0 μg/kg was injected within 30 minutes, and maintaining at 0.2-0.6 μg×kg⁻¹ × h⁻¹ for 24 hours; and in group B (propofol/+ morphine), propofol load 0.5-2.0 mg/kg was injected within 10 minutes, and maintaining at 1-3 mg×kg⁻¹×h⁻¹ for 72 hours. Patients with poor efficacy were added with morphine intravenously. In group C, intramuscular injection of pethidine and other temporary medication was injected. The comprehensive assessment was conducted according to the Riker sedation and agitation score, combined with the physiological body reaction positive indicator elimination. The vital signs was monitored, and blood white blood cell (WBC) count, blood sugar, cortisol and β-EP before and after administration were determined.

(1) The sedation efficiency rate of the group A, B, C were 84.38% (27/32), 80.64% (25/31), 77.78% (21/27), respectively. The booster dose of morphine in group A was less than that in group B (24 h dosage: 16.23 ± 3.45 mg vs. 21.34 ± 5.55 mg). (2) Blood pressure and heart rate were significantly affected in the group A. The mean arterial pressure (MAP) in 0.5 hour of reaching loading dose in group A was significantly lower than that in group B and C (75.50 ± 9.35 mm Hg vs. 87.90 ± 8.05 mm Hg, 85.70 ± 7.10 mm Hg, both P<0.05). (3) WBC and cortisol levels showed downwards trends after treatment in group A and group B; WBC fell more in the group A compared with group B, cortisol level fell more in group B compared with group A, and the WBC and cortisol level began to decline after 24 hours in group C. (4) There were no significant differences in blood sugar and β-EP levels before and after treatment in group B, but β-EP had an increasing tendency in group A and group C, and the amplification in group C was more obvious than that in group A.

The sedation efficacy of DEX was superior to propofol in moderate and severe TBI, and was able to control excessive stress response after TBI better, and with more effect on blood pressure. Plasma β-EP was elevated during the early phase of brain injury by DEX, which was considered as its positive role in the regulation of early stress.