Association between preoperative shock index and hypotension after spinal anesthesia for non-elective cesarean section: a prospective cohort study

Abstract

Abstract Background Shock index (SI) is calculated as heart rate divided by systolic blood pressure. In the obstetric population, SI of ≥ 0.9 is associated with maternal adverse outcomes. Our primary aim was to investigate the association between SI and post-spinal hypotension in non-elective cesarean section. Methods In this prospective, observational study, term parturient of ASA physical status II, and urgency categories 2 and 3, undergoing non-elective cesarean section with spinal anesthesia were enrolled. We performed univariable and multivariable logistic regression to explore the association between baseline SI (categorized as 4 (AOR, 2.33; 95%CI, 1.14–4.76; p = 0.020) were associated with post-spinal hypotension. Preoperative SI (AOR, 4.34; 95%CI, 1.72–10.94; p = 0.002) and anxiety (AOR,1.22; 95%CI, 1.06–1.40; p = 0.004) were associated with post-delivery hypotension. Area under the ROC curve for SI alone in predicting hypotension before and after delivery was 0.53 (95%CI 0.49–0.57) and 0.56 (95%CI 0.51–0.60) respectively. However, the model performance as reflected by ROC curve for the multivariable logistic regression analysis was 0.623 for post-spinal hypotension and 0.679 for post-delivery hypotension, respectively. Conclusion In parturients undergoing non-elective cesarean section, baseline SI ≥ 0.9 was associated with post-spinal and post-delivery hypotension. While the SI alone showed limited predictive power for post-spinal and post-delivery hypotension, integrating it with other risk factors improved the model's predictive ability. Trial registration Registration number: NCT04692870. Date of registration: 05/01/2021. Website: https://clinicaltrials.gov .

Keywords

• Cesarean section
• Hypotension
• Shock Index
• Spinal Anesthesia