The study is designed to compare the effectiveness of spinal anesthesia performed with fixed
dose of hyperbaric bupivacaine regardless of patient’s height and weight and anesthesia with
the dose of bupivacaine that is adjusted to their height. Our clinical experience shows that
spinal anesthesia using specific, relatively high dose of hyperbaric bupivacaine combined
with opioid is very effective, regardless of parturient’s weight and height, provides very
good surgical conditions and assures patient’s comfort while the rate of anesthesia – related
complications is similar or less. Therefore, using height-adjusted protocols, although
preferred in some centres, might not be necessary in order to provide good anaesthesia for
cesarean delivery. Fixed dose regimen may have some additional advantages in obstetric
anesthesia settings, as many of cesareans are performed out of hours, giving less room for
mistakes in less experienced hands.

Two groups of parturients undergoing cesarean section are to be compared: anesthetized with
fixed-dose regimen (intervention group) and anesthetized with height-adjusted dose regimen
(control group). Patients are going to be randomized to one of the above groups, two
anesthetists will be involved in anesthetic procedure: anesthetist that looks after the
patient throughout the procedure will be blinded to the dose of anesthetic given
intrathecally. Therefore his judgment of anesthetic effectiveness is not going to be biased
and all patients will receive the same perioperative care in terms of fluid therapy,
management of possible anesthesia – related complications and postoperative pain control.

Rate of effective spinal anesthetics, defined as adequate block level and no need for
additional intraoperative analgesia has been established as primary outcome measure.
Secondary outcome measures are rate of complications and amount of opioids used
postoperatively. These are going to be statistically compared.