///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

Predictors of vasopressor requirements to achievenormotensionin pregnant women undergoing cesarean delivery under spinal anesthesia.

Abstract Number: T2B-472
Abstract Type: Original Research

Shubhangi Singh MBBS, MD 1 ; Yun-Yun Chen MD2; Daniele Parise MD3; Vesela Kovacheva MD, MS4

Introduction: The administration of spinal anesthetic for cesarean delivery (CD) can lead to significant maternal hypotension which is associated with nausea, vomiting, lightheadedness, and in rare cases, stroke in the mother, as well as acidosis, hypoxia and low Apgar scores in the neonate. Prophylactic phenylephrine infusion is routinely used to prevent profound hypotension and improve the outcome for both mother and baby. Several studies have shown that factors like emergency CD, labor and lower preoperative anxiety can be associated with lower phenylephrine requirements, however there are no clear predictors to guide clinical decision making. In this study we sought to determine the risk factors associated with increased vasopressor needs in order to maintain normal maternal blood pressure.  

Methods:  We included all patients who had CD under spinal anesthesia in the past year in our tertiary institution and where the maternal systolic blood pressure was maintained 90-149 mmHg using phenylephrine infusion. Patients with any history of hypertension, preeclampsia or postural hypotension were excluded, as well as those with inadequate intraoperative blood pressure control or incomplete medical records.  Single- and multivariable linear regression models were used to predict the factors associated with the amount of phenylephrine used in the 20 minutes after the spinal injection.  

Results:  In our retrospective cohort of 259 patients, using one-factor linear regression, we found that the total amount of vasopressor used to maintain normotension is proportionate to the amount of bupivacaine in the spinal (P=0.02); there was no significant effect of age, BMI, presence of labor, parity, weeks of gestation, diabetes, depression and the weight of the baby. After adjusting for the amount of bupivacaine, there was still no significant effect of the above variables using multi-factor linear regression model (Table). 

Conclusion: We found strong association of the vasopressor utilization and the amount of bupivacaine administered in the spinal anesthetic. Our results suggest that patients, who receive higher bupivacaine amounts, are likely to need higher doses of prophylactic vasopressors  to maintain normal blood pressure. Further studies are needed to determine what other factors should be considered to guide vasopressor administration.

SOAP 2019