A Prospective Observational Study Evaluating the Nociception Level Index and Its Association With Pain Perception, Anxiety, Uterine Activity, and Autonomic Responses During Elective Cesarean Delivery Under Spinal Anesthesia
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 发起方
- 入组人数
- 100
- 试验地点
- 1
- 主要终点
- Percentage of intraoperative monitoring time during which the Nociception Level Index remains outside the predefined target range (10-25) during elective cesarean delivery under spinal anesthesia
研究概览
简要总结
The Nociception Level (NOL) Index is a multiparametric, non-invasive monitor that objectively assesses nociception by integrating several autonomic physiological signals. Although the NOL Index has been extensively validated during general anesthesia, its performance in awake patients undergoing regional anesthesia remains poorly understood. During cesarean delivery (CD) under spinal anesthesia, autonomic responses may be influenced not only by nociceptive stimulation but also by anxiety, uterine contractions, hemodynamic changes, uterotonic medications, and other non-nociceptive factors. Understanding the relative contribution of these factors is essential before the NOL Index can be reliably applied in awake surgical patients.
This prospective observational study aims to characterize the behavior of the NOL Index throughout elective CD performed under spinal anesthesia and to evaluate its relationship with subjective pain intensity, anxiety, uterine activity, perioperative autonomic responses, and routine physiological variables.
Approximately 100 women undergoing elective CD under spinal anesthesia will be enrolled at Carmel Medical Center. Continuous NOL monitoring using the PMD-200 system will be performed from before spinal anesthesia until the early postoperative period. Subjective pain (Visual Analog Scale), anxiety (Visual Analog Scale for Anxiety), uterine activity, hemodynamic variables, perioperative medications, and predefined surgical events will be prospectively recorded and synchronized with continuous NOL measurements. Potential confounding factors, including vasopressor administration, uterotonic drugs, nausea, shivering, patient movement, and supplemental analgesia, will also be documented.
This study will provide one of the first comprehensive evaluations of continuous NOL monitoring during CD under spinal anesthesia. The results are expected to improve the understanding of objective nociception monitoring in awake patients, clarify the influence of non-nociceptive autonomic activation on the NOL Index, and help define the clinical role and limitations of NOL monitoring during regional anesthesia, and may contribute to the future development of objective pain assessment strategies in obstetric anesthesia and other clinical settings involving awake patients.
详细描述
Elective cesarean delivery performed under spinal anesthesia provides a unique and highly reproducible clinical model for investigating objective nociception monitoring in awake patients. Unlike patients undergoing general anesthesia, women receiving spinal anesthesia remain conscious throughout surgery, allowing simultaneous assessment of subjective pain perception, anxiety, autonomic physiological responses, and objective nociception monitoring under standardized surgical conditions.
The Nociception Level (NOL) Index is a multiparametric physiological monitoring system that integrates several autonomic variables, including heart rate variability, skin conductance, photoplethysmographic waveform characteristics, and additional physiological parameters using a proprietary machine-learning algorithm. The NOL Index has been extensively validated during general anesthesia and has demonstrated good correlation with surgical stimulation and analgesic adequacy. However, its performance during regional anesthesia, particularly in awake obstetric patients, remains insufficiently characterized.
During cesarean delivery under spinal anesthesia, multiple physiological and psychological factors may influence autonomic nervous system activity independently of nociceptive stimulation. These include preoperative and intraoperative anxiety, emotional stress, patient communication, uterine manipulation, uterine contractions following administration of uterotonic agents, hemodynamic changes associated with neuraxial anesthesia, vasopressor administration, nausea, shivering, and patient movement. Consequently, interpretation of the NOL Index in this setting requires further clinical investigation.
This prospective, single-center observational study will enroll approximately 100 women undergoing elective cesarean delivery under spinal anesthesia at Carmel Medical Center, Haifa, Israel. Standard perioperative management will not be modified for study purposes. Continuous NOL monitoring will begin before initiation of spinal anesthesia and continue throughout surgery and the early postoperative recovery period.
Simultaneously, subjective pain intensity will be assessed using the Visual Analog Scale (VAS), anxiety will be evaluated using the Visual Analog Scale for Anxiety (VAS-A), and routine physiological variables including heart rate, blood pressure, mean arterial pressure, and oxygen saturation will be recorded. Surgical milestones, administration of intrathecal medications, uterotonic agents, vasopressors, rescue analgesia, and other clinically relevant medications will be prospectively documented and synchronized with continuous NOL recordings.
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 40 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 否
入选标准
- •Women ≥18 years
- •Scheduled to elective cesarean delivery under spinal anesthesia
- •ASA I-III
- •Able to provide informed consent
排除标准
- •Women Age <18 years
- •BMI >35 kg/m²
- •Major psychiatric illness
- •Chronic psychotropic/anxiolytic therapy
- •Substance abuse
- •Inability to communicate
- •Contraindication to spinal anesthesia
- •Any pre condition interfering with study participation
结局指标
主要结局
Percentage of intraoperative monitoring time during which the Nociception Level Index remains outside the predefined target range (10-25) during elective cesarean delivery under spinal anesthesia
时间窗: Intraoperative period up to 3 hours
Nociception Level Index a physiological parameter measurment obtained, in a non invasive way, by a probe attached to the index finger, recording every 5 seconds. (range 0-100) 0 no pain 100 worst pain
次要结局
- Duration of Nociception Level Index (>25)(Intraoperative period and approximately 1 hour postoperatively, up to 5 hours)
- Correlation between Nociception Level Index and Visual Analog Scale(: Intraoperative period and approximately 1 hour postoperatively up to 5 hours)
- Correlation between Nociception Level Index and Visual Analogue Scale- anxiety(Intraoperative period and approximately 1 hour postoperatively up to 5 hours)
- Surgical phase analysis(Intraoperative period and approximately 1 hour postoperatively)
- Association of Nociception Level Index with uterine activity(Intraoperative period and approximately 1 hour postoperatively up to 5 hours)
- Rescue analgesia requirements(Intraoperative period and approximately 1 hour postoperatively up to 5 hours)
研究者
Michael Grach
MD Dr. Michael Grach Director of pain medicine clinic
Carmel Medical Center