Correlation of Symphysiofundal Height and Abdominal Girth with the Incidence of Hypotension in Cesarean Section Under Spinal Anesthesia using Bupivacaine with Fentanyl as Adjuvant: A Clinical Study

Risk factors of more severe hypotension after spinal anesthesia for cesarean section

BACKGROUND

The aim of this study was to examine the risk factors associated with the use of vasopressors to prevent hypotension that occurs after spinal anesthesia during cesarean section. Although the prophylactic use of vasopressors is already suggested as routine care in many parts of the world, the occurrence of spinal anesthesia-induced hypotension (SAIH) is still common in parturients.

METHODS

This retrospective study included parturients receiving elective cesarean deliveries under spinal anesthesia from April 2016 to March 2020. Risk factors related to ephedrine dosage were analyzed using a hurdle model, and risk factors related to SAIH were further analyzed with logistic regression.

RESULTS

Five risk factors, namely maternal body mass index (BMI, p < 0.001), baseline systolic blood pressure (SBP, p < 0.001), baseline heart rate (HR, p = 0.047), multiparity ( p = 0.003), and large fetal weight ( p = 0.005) were significantly associated with the requirement for ephedrine. Furthermore, a higher ephedrine dosage was significantly associated with maternal BMI ( p < 0.001), baseline SBP ( p < 0.001), baseline HR ( p < 0.001), multiparity ( p = 0.027), large fetal weight ( p = 0.030), maternal age ( p = 0.009), and twin pregnancies ( p < 0.001). Logistic regression analysis also showed that the same five risk factors-maternal BMI ( p = 0.030), baseline SBP ( p < 0.001), baseline HR ( p < 0.001), multiparity ( p < 0.001), and large fetal weight ( p < 0.001)-were significantly associated with SAIH, even in cases where vasopressors were administered.

CONCLUSION

These findings can be useful for clinicians when deciding the dose of prophylactic ephedrine or phenylephrine to prevent SAIH.

Prediction of spinal anesthesia-induced hypotension during elective cesarean section: a systematic review of prospective observational studies

BACKGROUND

Spinal anesthesia is the standard for elective cesarean section but spinal anesthesia-induced hypotension remains an important problem. Accurate prediction of hypotension could enhance clinical decision-making, alter management, and facilitate early intervention. We performed a systematic review of predictors of spinal anesthesia-induced hypotension and their predictive value during cesarean section.

METHODS

PubMed, Embase, Cochrane Library, Google Scholar and Web of Science databases were searched for prospective observational studies assessing the diagnostic accuracy of predictors of spinal anesthesia-induced hypotension in elective cesarean section. The quality of studies was assessed and predictors were grouped in domains based on the type of predictor.

RESULTS

Thirty-eight studies (n=3086 patients) were included. In most studies, patients received 500-1000 mL crystalloid preload or 500-2000 mL crystalloid coload. Vasopressors for post-spinal hypotension were boluses of ephedrine 5-15 mg and/or phenylephrine 25-100 µg in most studies. The hypotension rate varied from 29% to 80% based on the definition. For analysis, >30 predictors were classified into seven domains: demographic characteristics, baseline hemodynamic variables, baseline sympathovagal balance, postural stress testing, peripheral perfusion indices, blood volume and fluid responsiveness indices, and genetic polymorphism.

CONCLUSIONS

Environmental and individual factors increased outcome variability, which restricted the value of the autonomic nervous system and peripheral perfusion indices for prediction of spinal anesthesia-induced hypotension. Supine stress tests may reflect parturients' cardiovascular tolerance during hemodynamic fluctuations and may optimize the predictive value of static state predictors. Future research for predicting spinal anesthesia-induced hypotension should focus on composite and dynamic parameters during the supine stress tests.