ED90 of Norepinephrine and Phenylephrine Infusions Under Intensive Treatment

An initial infusion dose of prophylactic norepinephrine (0.05 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.01 ug/kg/min of prophylactic norepinephrine according to the responses of previous patients according to the up-down sequential allocation.

An initial infusion dose of prophylactic phenylephrine (0.5 ug/kg/min) simultaneous with spinal anesthesia. The dose administered to subsequent patients varied by increments or decrements of 0.1 ug/kg/min of prophylactic phenylephrine according to the responses of previous patients according to the up-down sequential allocation.