ET 50 for Post Caesarean Section Spinal Hypotension

Summary

Hypotension is extremely common after induction of spinal anesthesia for cesarean delivery. Anesthetic blockade of the sympathetic outflow of the spinal cord causes vasodilation, and is one cause of this hypotension. The higher the spread of the blockade will result in a higher incidence of hypotension. Injected hyperbaric medication has about 15 minutes to spread within the intrathecal space before it will be taken up by the nerve roots. The time that a patient remains in one position after medication injection will affect the spread of the resultant anesthetic block. A patient who is left sitting for a longer period of time after injection of hyperbaric medication will have a lower level of block than someone who is placed supine immediately. In this study, the investigators wish to use up down sequential analysis to determine the time period a patient should remain seated after intrathecal injection of hyperbaric bupivacaine that will result in a 50% rate of hypotension.

Timeline

Start

2012-03

Primary completion

2014-03

Completion

2014-05

Publications

• Chooi C, Cox JJ, Lumb RS, Middleton P, Chemali M, Emmett RS, Simmons SW, Cyna AM. Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst Rev. 2020 Jul 1;7(7):CD002251. doi: 10.1002/14651858.CD002251.pub4.
• Moore A, Bourrassa-Blanchette S, El Mouallem E, Kaufman I, El-Bahrawy A, Li-Pi-Shan W, Hatzakorzian R. The median effective seated time for hypotension induced by spinal anesthesia at Cesarean delivery with two doses of hyperbaric bupivacaine: a randomized up-down sequential allocation study. Can J Anaesth. 2014 Oct;61(10):916-21. doi: 10.1007/s12630-014-0208-8. Epub 2014 Jul 24.

Drugs

Indications