Comparison of the Effect of Low-dose and Standard-dose Dexmedetomidine Infusion on Neurological Outcomes in Patients With Aneurysmal Subarachnoid Hemorrhage Undergoing Aneurysmal Neck Clipping: a Randomized Controlled Trial.

BACKGROUND

Recent studies have shown a potential neuroprotective role of dexmedetomidine in subarachnoid hemorrhage. However, its effect on neurological outcomes and optimal dosing regimen remains unclear.

METHODS

We randomized 75 adults with good grade aneurysmal subarachnoid hemorrhage undergoing clipping to receive dexmedetomidine, low-dose (Group D1,0.2 μg kg -1  h -1 , n = 25), standard dose (Group D2, 0.5 μg kg -1  h -1 , n = 25), or normal saline (Group C, n = 25) commenced postinduction of anesthesia and continued for 24 hours. Our primary objective was to assess rates of good functional outcome, defined as a modified Rankin Scale (mRS) Score of 0 to 2, at hospital discharge. Secondary outcomes included rates of good functional outcome at 3 months, levels of blood lactate, S100β, and Neuron Specific Enolase (NSE), incidence of vasospasm, delayed cerebral ischemia (DCI), and cerebral dysautoregulation.

RESULTS

Neurological outcome at discharge was better in Group D1 as compared to Group C (mRS 0 to 2, Group D1 vs. C; 19 (76%) vs. 9 (36%), P = 0.02), while it was similar in Group D2 as compared to D1 and C. Neurological outcome at 3 months was comparable among the 3 groups. The lactate levels were significantly lower in Group D1 as compared to Groups D2 and C at 12 and 24 hours. The levels of NSE and S100β were significantly lower in D1 and D2 as compared to Group C. Other measured parameters were comparable.

CONCLUSION

Low-dose dexmedetomidine was associated with a favourable neurological outcome at discharge compared to the control group. Larger trials are necessary to conclusively establish the neuroprotective effect of dexmedetomidine.