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

Personalized Hemodynamics: A Statistical Model Predicting The Changes In Maternal Systolic Blood Pressure After Spinal Anesthesia for Cesarean Delivery

Abstract Number: T2B-496
Abstract Type: Original Research

Daniele Parise M.D.1 ; Yun-Yun Chen M.D.2; Shubangi Singh M.B.B.S.3; Kara Fields B.S. 4; Vesela Kovacheva M.D.5

Introduction: Maternal hypotension after spinal anesthesia can pose significant risk for both the mother: lightheadedness, nausea, ultimately, end-organ hypoperfusion; and the fetus: acidosis, hypoxia, and low APGAR scores. Prophylactic vasopressor administration may result in under- or over-treatment of maternal systolic blood pressure (SBP) and present risk for both mother and baby safety. There is little evidence-based guidance about the administration of vasopressors due to the challenges of predicting the maternal SBP course after the onset of spinal anesthesia. The aim of this study is to create a statistical model to prognosticate the next SBP in pregnant women undergoing cesarean delivery under spinal anesthesia.

Methods: We included healthy patients who had cesarean delivery under spinal anesthesia and excluded any patients with history of hypertension, preeclampsia, baseline SBP<90mmHg or incomplete records. We used the vital signs and vasopressor doses from intraoperative records in the 5 minutes before and after spinal anesthesia. A linear mixed-effects model with a gaussian random intercept was used to estimate the association of the following fixed effects with change in SBP from baseline at the next minute: age, BMI, mean baseline SBP, mean baseline HR, amount of bupivacaine, current SBP change from baseline, and current cumulative vasopressor dose. Model fit was assessed by calculating the marginal pseudo-R2 (the variance explained by fixed effects) and conditional pseudo-R2 (the variance explained by entire model) for generalized mixed-effect models.

Results: We used 386 high quality patient records. The average age was 34.34.6 years and the average BMI was 30.45.6 kg/m2. The mean baseline SBP was 128.7 13.3 mmHg and the mean baseline HR was 92.714.7 bpm. Using linear mixed effects model (Table 1), we found that a change in SBP from baseline at the current timepoint explains 65.9% of the variability in change in SBP from baseline at the next timepoint.

Conclusion: We created a predictive model of the changes in maternal SBP after spinal anesthesia. Our next steps will be to determine the corresponding amounts of vasopressor needed to maintain normal SBP. These results will help refine vasopressor administration and tailor the dose to the particular patient, which will ultimately increase the safety of both mother and baby.

SOAP 2019