Investigation of the Optimum Baseline Blood Pressure for Spinal Anesthesia to Guide Vasopressor Management for Elective Cesarean Delivery: A Case-Control Design

Vesela P Kovacheva; William Armero; Guohai Zhou; David Bishop; Robert Dyer; Brendan Carvalho

doi:10.7759/cureus.45380

Investigation of the Optimum Baseline Blood Pressure for Spinal Anesthesia to Guide Vasopressor Management for Elective Cesarean Delivery: A Case-Control Design

Cureus. 2023 Sep 16;15(9):e45380. doi: 10.7759/cureus.45380. eCollection 2023 Sep.

Authors

Vesela P Kovacheva¹, William Armero², Guohai Zhou³, David Bishop⁴, Robert Dyer⁵, Brendan Carvalho⁶

Affiliations

¹ Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, USA.
² Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, USA.
³ Center for Clinical Investigation, Brigham and Women's Hospital, Boston, USA.
⁴ Anaesthetics, Critical Care and Pain Management, University of KwaZulu-Natal, Scottsville, ZAF.
⁵ Anaesthesia and Perioperative Medicine, Groote Schuur Hospital Observatory, University of Cape Town, Cape Town, ZAF.
⁶ Anesthesiology, Stanford University, Stanford, USA.

Abstract

Background: Current guidelines recommend prophylactic vasopressor administration during spinal anesthesia for cesarean delivery to maintain intraoperative blood pressure above 90% of the baseline value. We sought to determine the optimum baseline mean arterial pressure (MAP) reading to guide the management of spinal hypotension.

Methods: We performed a secondary analysis of data collected from normotensive patients presenting for elective cesarean delivery in a tertiary care institution from October 2018 to August 2020. We compared the magnitude of hypotension in patients who reported nausea versus those who did not, using a case-control design. Baseline MAPs at last office visit, morning of surgery, or operating room (pre-spinal) were determined. We calculated the duration and degree of hypotension using the area under the curve (AUC) when the MAP of the respective patient was below 90% of each baseline.

Results: The patients who experienced nausea (n=45) had longer and more profound periods of hypotension than those who did not develop nausea (n=240). A comparison of AUC using MAP baseline at the last office visit or on the morning of surgery showed a statistically significant between-group difference, P=0.02, and P=0.005, respectively, and no significant between-group difference when 90% of the MAP baseline in the operating room was used.

Conclusions: Patients had the highest preoperative MAP in the operating room and the AUC was similar for those with and without nausea when the pre-spinal MAP baseline was used. Therefore, maintaining higher intraoperative blood pressure using individual pre-spinal MAP as baseline should reduce intraoperative maternal nausea.

Keywords: blood pressure; cesarean; intraoperative; mean arterial pressure; phenylephrine; prophylactic vasopressor administration; spinal anesthesia; spinal hypotension.