Pupillary Light Reflex for Predicting Hypotension Risk After Spinal Anesthesia for Elective Cesarean Section: A Prospective Observational Cohort Study
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 200
- 主要终点
- Incidence of Hypotension After Spinal Anesthesia
研究概览
简要总结
This prospective observational cohort study investigates whether pre-anesthetic pupillary light reflex (PLR) parameters can predict the risk of hypotension following spinal anesthesia in women undergoing elective cesarean section. Spinal anesthesia-induced hypotension is common, with reported incidence rates of 50-90%, and current predictors such as baseline blood pressure and BMI have limited accuracy. PLR, a sensitive marker of autonomic nervous system balance, may offer a simple, objective, and non-invasive tool for identifying patients at higher risk. The study evaluates pupillary reaction latency and other PLR parameters and correlates them with post-spinal blood pressure changes to determine their predictive value.
详细描述
Spinal anesthesia is the standard technique for elective cesarean delivery, yet it is frequently associated with maternal hypotension due to sympathetic blockade. According to the study protocol, spinal anesthesia-induced hypotension (SAIH) occurs in 50-90% of cases, and currently available predictors-including baseline blood pressure, BMI, and block height-demonstrate limited accuracy (AUC <0.65). The pupillary light reflex (PLR) is a sensitive indicator of autonomic nervous system balance, and pupillary reaction latency may reflect parasympathetic conduction efficiency. As noted in the protocol, no published studies have evaluated PLR as a predictor of hypotension after spinal anesthesia in obstetric patients.
This prospective observational cohort study aims to determine whether pre-anesthetic PLR parameters, particularly pupillary reaction latency, can predict the occurrence and severity of hypotension following spinal anesthesia for elective cesarean section. Additional pupillometry parameters-including baseline diameter, constriction velocity, and minimum diameter-will also be assessed. Measurements are obtained using a handheld pupillometer after 5 minutes of dark adaptation, with three readings taken at 60-second intervals.
Following spinal anesthesia with hyperbaric bupivacaine and fentanyl, maternal blood pressure is monitored every 5 minutes for the first 20 minutes. The primary outcome is hypotension, defined as a >20% decrease in systolic blood pressure. Secondary outcomes include severe hypotension, vasopressor requirements, maternal symptoms, and neonatal Apgar scores and umbilical artery pH.
Statistical analysis includes ROC curve evaluation, Youden's index for cutoff determination, and multivariate logistic regression. The study involves no interventions beyond routine care, and pupillometry is non-invasive and safe. Findings may support the development of a novel, objective, and clinically useful predictor for SAIH in obstetric anesthesia.
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 Years 至 45 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •ASA II Term pregnancy ≥37 weeks Singleton pregnancy Elective cesarean section Age 18-45 years Written informed consent
排除标准
- •Emergency cesarean section Hypertensive disorders Diabetes mellitus Cardiovascular disease Neurological or autonomic disorders Ophthalmic disease Medications affecting autonomic function BMI >40 kg/m² Failed spinal anesthesia
结局指标
主要结局
Incidence of Hypotension After Spinal Anesthesia
时间窗: 0-20 minutes after spinal anesthesia
Hypotension defined as a \>20% decrease in systolic blood pressure from baseline within the first 20 minutes after spinal anesthesia administration. Blood pressure is measured every 5 minutes as per protocol.
次要结局
- Neonatal Apgar Scores(1 minute and 5 minutes postpartum)
- Incidence of Severe Hypotension(0-20 minutes after spinal anesthesia)
- Total Vasopressor Dose Administered(Intraoperative period (first 20 minutes post-spinal))
- Maternal Symptoms Associated With Hypotension(Intraoperative period)
- Umbilical Artery pH(Immediately after delivery)
研究者
Tarik Saber Sarhan
Assistant Professor of Anesthesiology, Intensive Care and Pain Management
Al-Azhar University