Evaluation of Objective Pain Measurement Device

This study will attempt to objectively measure pain with an experimental device. The investigators will apply the device to measure patients "pain" due to uterine contractions during routine clinical care to correlate patients verbal pain ratings and analgesia requirements to that measured by the device. A brain oxygenation device, Edwards Foresight, will be used to concurrently to monitor brain oxygenation and hemodynamics, so the relationship between the CereVu ROPA device objective measure of pain and brain oxygenation/hemodynamic changes and patient-reported pain can be determined.

Despite all the progress in our understanding of the basic mechanisms of pain, the gold standard for measuring pain is still a subjective verbal numeric rating scale rating (0-10) obtained from the individual reporting pain. This method is not objective and cannot be used in all patient populations. This study will attempt to objectively measure pain in laboring mothers with a pain measurement device. The investigators aim to 1) see if the pain measurement device (CereVu ROPA) is capable of reflecting different levels of pain ratings in patients in labor having uterine contractions and then changes in pain after receiving different neuraxial techniques for labor pain and to 2) additionally determine the relationship between the CereVu ROPA device, brain oxygenation/hemodynamic changes and patient-reported pain scores.

When participants request labor analgesia, the sensors of the pain measurement device (ROPA System [CereVu Medical, Inc. San Francisco, CA] and Edwards Foresight device) will be applied to the forehead and connected to the device. Data recording is then started.

Correlation between patient self-reported pain score on 0 to 10 scale (higher scores correspond to more pain) and brain oxygenation (0-100%). This outcome will be assessed in part 2 only.

Correlation between patient self-reported pain score on 0 to 10 scale (higher scores correspond to more pain) and hemodynamic parameter noninvasive blood pressure. This outcome will be assessed in part 2 only.

Correlation between patient self-reported pain score on 0 to 10 scale (higher scores correspond to more pain) and hemodynamic parameter heart rate. This outcome will be assessed in part 2 only.

Correlation between patient self-reported pain score on 0 to 10 scale (higher scores correspond to more pain) and hemodynamic parameter pulse oximetry. This outcome will be assessed in part 2 only.

Inclusion Criteria: Age 18-50 ASA 1 or 3 +/-E Patient requesting epidural labor analgesia Good toco tracing (clearly showing contractions at least every 5 minutes) Pain score greater than or equal to 3 out of 10 with contractions Exclusion Criteria: History of chronic pain History of chronic opioid use BMI > 45 Allergy to sensor adhesive material, local anesthetic or opioids Contraindication to neuraxial block Patient on magnesium infusion Inability to give informed consent or understand English