The Application of Analgesia Nociception Index as an Objective Labor Pain Assessment During Epidural Analgesia

Changhua Christian Hospital, Department of Anesthesiology

Epidural analgesia is considered an effective and safe method for obstetric pain control. Currently, self-assessment pain scales remain to be the gold standard in labor pain evaluation after the administration of epidural analgesia. However, individual patient susceptibility to pain perception makes difficulties for the clinicians to assess the effectiveness of painless labor precisely. The aim of this study is to evaluate the validity of ANI in obstetric pain monitoring during epidural analgesia.

Epidural analgesia is considered an effective and safe method for obstetric pain control. Currently, self-assessment pain scales remain to be the gold standard in labor pain evaluation after the administration of epidural analgesia. However, individual patient susceptibility to pain perception makes difficulties for the clinicians to assess the effectiveness of painless labor precisely. Without a convincing objective tool for obstetric pain evaluation during epidural analgesia, the clinicians are hard to adjust adequate epidural drug dosage. Establishing an objective pain index would help the clinicians to have a better pain management during labor.

In 2012, M. Le Guen et al. demonstrated a linear relationship between visual analogical pain scores(VAS) and Analgesia Nociception Index (ANI) values during labor. Their efforts started the application of ANI in obstetric pain monitoring. However, the reliability of ANI in obstetric pain monitoring under epidural analgesia have not yet been verified. The aim of this study is to evaluate the validity of ANI in obstetric pain monitoring during epidural analgesia.

Inclusion Criteria:

• Parturients with gestational age more than 35 weeks
• Ages between 20 to 50
• Received epidural analgesia
• American Society of Anesthesiologists classification I or II.

Exclusion Criteria:

• 1. Who refused to join the study
• 2. With a history of arrhythmia
• 3. American Society of Anesthesiologists (ASA)Classification >= III
• 4. With a history of cardiovascular, pulmonary, endocrine, neurologic or psychiatric disease
• 5.Using medications that affecting heart rate
• 6. Cannot understand the explanation of the study
• 7. High-risk gestation
• 8. Known fetal anomaly