///2015 Abstract Details
2015 Abstract Details2019-08-02T16:54:43-06:00

Developing and Testing an Objective Pain Measurement Device in Laboring Women

Abstract Number: T-07
Abstract Type: Original Research

Benjamin G Cobb MD1 ; Naola Austin MD2; Alexander Tzabazis MD3; Andreas Eisenried MD, MS4; Brendan Carvalho MBBCh, FRCA, MDCH5

Introduction: There are currently no reliable, commercially available, objective pain measurement devices.[1] This study aimed to perform algorithm calibration and testing for a novel pain measurement device for labor pain and neuraxial analgesia evaluation.

Methods: 15 healthy pregnant women requesting epidural labor analgesia were enrolled in this IRB-approved, prospective cohort study. A non-invasive, adhesive sensor (Covidien NellcorTM) was placed on the subject’s forehead and connected to the pain measurement device in development (ROPAMedics, LLC). An independent investigator recorded timing and numerical rating pain scores (NRS) of contractions and other painful events. The study started at setup for epidural analgesia and ended with achievement of analgesia (NRS ≤2 with contractions). Patients received an epidural (5+5+5 ml 0.125% bupivacaine + sufentanil 10 mcg) or combined-spinal epidural (bupivacaine 2.5 mg + sufentanil 5 mcg). De-identified data was then used by ROPAMedics to calibrate an algorithm that calculates Real-Time Cerebral Hemodynamic Response (RTCHR). RTCHR is a measure of frontal lobe cortical activity, driven by regional changes in oxygenated and deoxygenated hemoglobin concentration, which has been shown to correlate with pain or nociception.[2] Correlation analysis was performed using Spearman’s rank or Kendall-Tau, as appropriate, to assess the relationship between RTCHR recordings and patient-reported pain NRS.

Results: The study protocol was successfully applied to 15 laboring women. A representative patient dataset showing overlay of events during the study period, fetal heart rate, uterine contractions, and RTCHR measurements is shown in Fig 1A. The Kendall-Tau correlation coefficient between measured RTCHR and patient-reported pain NRS was strong and statistically significant (0.81, p<0.001;Fig 1B).

Discussion: An objective pain measurement device would be invaluable for patients who cannot verbalize pain scores, such as infants or sedated patients, or could complement subjective pain scores to prevent under or over treatment of pain. Laboring women receiving neuraxial analgesia provided an excellent study population for device algorithm development and calibration. Double-blinded studies to validate and further develop this novel pain measurement tool in obstetric and non-obstetric subjects are ongoing.


1. J Pain. 2009;10(10):1001-11

2. J Neurosci. 2006;26(14):3662-6

SOAP 2015