ED90 for Hyperbaric Bupivacaine in Super Obese Parturients

Determination of the dose will rely on the outcomes of the preceding 7 patients receiving the same dose, as the number of previous patients to consider is a function of the target dose. Among all patients who received a certain dose, a proportion of successful outcomes will be determined (P(d)); if P(d) \<0.90, and at least one of the previous 7 patients who received the same dose had an unsatisfactory outcome, the next patient will receive a pre-determined increment of 0.75 mg of bupivacaine. Alternatively, if P(d) 0.90 and the previous 7 patients who received the same dose had successful outcomes, the next patient will receive a pre-determined decrement of 0.75mg of bupivacaine. Otherwise, the dose will remain the same.