Norepinephrine ED90 Bolus After Spinal Anesthesia in Cesarean Section

"The outcome of patient n in each sequence will determine the dose to be allocated patient n+1.~Successive doses will be determined with the up-and-down k-in-row design method for ED90 determination:~* Failure: the dose should be increased in one level (+0.02 µg/kg) after failure to respond (arterial hypotension);~* Success: decrease in one level (-0.02 µg/kg) upon successful response (no arterial hypotension), but only after observing at least k-consecutive positive responses at the same dose (in this case, k=7); otherwise, remain at the same dose.~This will be done until each sequence completes n=30."