Preop Dexmedetomidine Attenuates Haemodynamic Responses to Hydrodissection

"After induction as mentioned at 'arm description', the effect-site propofol concentration was fixed at 5.0 μg mL-1 at the time of diluted epinephrine injection and was unchanged during the entire hydrodissection period in all patients.~The first patients received effect-site concentrations of remifentanil of 4 ng mL -1, respectively. The EC50 of remifentanil for stable hydrodissection was determined by a modification of Dixon's up-and-down method.If the response was success (SBP during the entire hydrodissection period being ±20% from baseline), the next target concentration of remifentanil was decreased by a step of 0.5 ng mL -1. If the response was fail(SBP \> ±20% from baseline), the target concentration was increased by 0.5 ng mL-1."

All procedure would be same in DXM+Propofol group except saline loading rather than DXM loading before induction.