The safest form of anesthesia for Cesarean section is a spinal anesthetic. All spinal anesthetics contain a local anesthetic and/or a narcotic. A drug named bupivacaine is the most commonly used local anesthetic in spinal anesthetics for Cesarean deliveries in North America. Another drug named fentanyl is the most commonly used narcotic. This study will look at whether a spinal anesthetic with 15mg of bupivacaine alone will be the same as a spinal anesthetic with 12mg of bupivacaine and 15ug of fentanyl.

There have been many studies looking at different doses and combinations of bupivacaine and fentanyl but there is no agreement among anesthesiologists as to the best combination of drugs.

The main problem with bupivacaine is that it causes hypotension (low blood pressure). When fentanyl is added to bupivacaine, a lower dose of bupivacaine can be used so that there is less of a fall in blood pressure. The main problem with fentanyl is itchiness and sleepiness. In the case of an emergency Cesarean section, the extra time needed to draw-up and administer a second medication may make a difference to the health of the baby.

Our goal is to determine whether high dose bupivacaine (15mg) alone will produce spinal anaesthesia for cesarean delivery equivalent to 12mg of intrathecal hyperbaric bupivacaine in combination with 15ug of intrathecal fentanyl.

Inclusion Criteria:

• healthy patients (ASA 1 or 2)
• BMI < 40
• height between 5 & 6 feet

Exclusion Criteria:

• parturients with pregnancy induced hypertension or preeclampsia
• parturients with significant cardiac, renal or other organ-system disease which preclude choice of spinal anesthesia
• emergency delivery
• triplet or greater multiple gestation