The Value of Waist Circumference, Body Mass Index, and Modified Shock Index in Predicting Spinal Anesthesia-Induced Hypotension During Cesarean Section: A Prospective Observational Study
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 321
- 试验地点
- 1
- 主要终点
- Incidence of Spinal Anesthesia-Induced Hypotension (SAIH)
研究概览
简要总结
This prospective observational study investigates the predictive value of anthropometric and hemodynamic indices for spinal anesthesia-induced hypotension (SAIH) during cesarean section. While spinal anesthesia is preferred for its rapid onset, SAIH remains a frequent complication risking maternal and fetal safety. The study enrolled parturients at Erciyes University, excluding those with hypertension or extreme weight/height. Preoperative measurements included BMI, waist circumference (WC), body roundness index (BRI), and modified shock index (MSI). Following standardized spinal anesthesia with hyperbaric bupivacaine (Harten's dosage), hemodynamic parameters and sensory block levels were monitored. This research aims to determine whether BRI and WC offer superior predictive utility compared with conventional markers such as BMI and MSI to enhance individualized risk assessment in obstetric anesthesia.
详细描述
Spinal anesthesia is the preferred anesthetic technique for cesarean section due to its rapid onset, reliability, and minimal neonatal drug exposure. However, spinal anesthesia-induced hypotension (SAIH) remains the most common and clinically significant complication, with an incidence ranging between 10% and 80% of parturients. The resulting maternal hypotension can lead to symptoms such as nausea, vomiting, and dizziness. At the same time, severe or sustained decreases in blood pressure may compromise uteroplacental perfusion, causing fetal acidosis and distress. Therefore, early prediction and prevention of hypotension are paramount to ensure maternal and neonatal safety.
Several hemodynamic and anthropometric factors have been investigated as potential predictors of SAIH, including baseline blood pressure, heart rate, and indices reflecting intravascular volume or autonomic tone. Among these, the modified shock index (MSI), calculated as the ratio of heart rate to mean arterial pressure, has been proposed as a noninvasive marker of hemodynamic stability and cardiovascular reserve. Likewise, body mass index (BMI), waist circumference (WC), and the body roundness index (BRI) have been associated with alterations in central blood volume, vascular compliance, and sympathetic responsiveness, which may influence susceptibility to post-spinal hypotension.
Pregnancy induces profound physiological changes, including decreased systemic vascular resistance and increased circulating blood volume, which alter cardiovascular responses to sympathetic blockade. These adaptations may interact with individual body composition and baseline hemodynamic parameters, modifying the risk of hypotension. Despite these associations, the predictive utility of anthropometric indices, such as BRI and WC, alongside conventional measures like BMI and MSI, has not been clearly established in obstetric anesthesia.
Symphyseal fundal height (SFH) and AC measurements indirectly indicate compression of the inferior vena cava (IVC). AC and VCL have previously been found to be highly predictive of block level in operations of non-pregnant patients performed under SA with isobaric bupivacaine.
Therefore, this prospective observational study was designed to evaluate the predictive value of waist circumference, body roundness index, body mass index, and modified shock index in identifying parturients at risk for spinal anesthesia-induced hypotension during cesarean delivery. By determining reliable preoperative indicators, this study aims to contribute to individualized risk assessment and the development of preventive strategies in obstetric anesthesia practice.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Months 至 45 Months（Child）
- 性别
- Female
- 接受健康志愿者
- 否
入选标准
- •American Society of Anesthesiologists (ASA) Physical Status Class II, The patients had regular antenatal visits. Singleton pregnancy at >37 weeks of gestation, Pregnant women aged between 18 and 45 years
排除标准
- •Clinical diagnosis of preeclampsia or eclampsia
- •Emergency cesarean section
- •The patients had bleeding diathesis or were receiving anticoagulant therapy
- •History of carotid artery stenosis
- •Clinical diagnosis of cardiovascular disease
- •Clinical diagnosis of hypertension (chronic or pregnancy-induced)
- •Clinical diagnosis of chronic obstructive pulmonary disease (COPD)
- •Clinical diagnosis of non-sinus cardiac rhythm (e.g., arrhythmias)
- •History of cerebrovascular disease
- •Alcoholism or psychiatric disorders
- •Clinical diagnosis of placenta previa, accreta, or percreta
- •Clinical diagnosis of diabetes mellitus
- •Contraindications to spinal anesthesia (e.g., patient refusal, infection at the injection site)
- •Failed spinal block
结局指标
主要结局
Incidence of Spinal Anesthesia-Induced Hypotension (SAIH)
时间窗: From the time of spinal bupivacaine administration up to 30 minutes post-administration.
The presence or absence of hypotension (binary variable) will be recorded. The predictive power of the independent variables (BMI, BRI, WC, MSI) for this condition will be evaluated using logistic regression. Nagelkerke's $R\^2$ was treated as a component of the analysis procedure, not as a measurement unit.
次要结局
未报告次要终点
研究者
Kudret Dogru
Prof. Dr. MD
TC Erciyes University