SKIN WHEAL - Subcutaneous or Intradermal Lidocaine in Epidural for Laboring Pain.

The purpose of this study is to explore the differences between the pain associated with epidural Tuohy needle insertion with prior administration of subcutaneous or intradermal lidocaine using two different pain assessment tools (numerical rate scale (NRS) and Critical-Care Pain Observation Tool (CPOT)) in parturient women requesting epidural analgesia for laboring pain. Subjects will go through the following study procedures: review of medical history prior to surgery. Subjects will be randomly assigned to one of the two study groups in a 1:1 ratio to one of the two different standard methods to administer lidocaine prior to epidural Tuohy needle insertion: intradermal or subcutaneous lidocaine administration. Prior to insertion of the Tuohy epidural needle, each patient will receive an injection of 3 mL 1% lidocaine either intradermally (Group Intradermal) or subcutaneously (Group Subcutaneous). A blinded observer (positioned in front of the patient and unable to see the procedure) will record baseline NRS scores, HR, and BP after the patient has been positioned for the epidural procedure and prior to the administration of lidocaine. During the procedure, the blinded observer will objectively record patient's vocal responses, facial expressions, bodily movements, and muscle tension (caused by pain reflex) using the CPOT and NRS scales during lidocaine administration and the first Tuohy needle insertion. After each injection, the blinded observer will record the corresponding heart rate. When the procedural anesthesiologist has exited the room, the blinded observer will then collect the patient's procedure satisfaction score from 0 (worst satisfaction) to 10 (most satisfaction) at the conclusion of the procedure. Likewise, the blinded observer will also collect the final post-procedure heart rate and blood pressure.

EXPERIMENTAL METHODS Study design: A single center, prospective, randomized, double blind pilot study for the evaluation of pain due to epidural Tuohy needle insertion with prior administration of subcutaneous or intradermal administration of lidocaine in parturient women requesting epidural analgesia for laboring pain at The Ohio State University Wexner Medical Center - Obstetric Anesthesia Division.

Sample size: Since this is a pilot study, 25 patients with complete data in each group will be needed for the study, as no single study has been found to help sample size calculations. We estimated 25 patients per group (Intradermal Group and Subcutaneous Group) will be required to learn more about procedural pain on this patient population. However, we are requesting to consent 60 subjects in total, accounting for 20% of screen failure and/or early termination. A total of 60 patients will be included.

Study Population: Parturient women requesting epidural analgesia for laboring pain at The Ohio State University Wexner Medical Center - Obstetric Anesthesia Division.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 18 years old
* Parturient women requesting epidural analgesia for laboring pain
* Ability to consent in English language

Exclusion Criteria:

* Women undergoing cesarean delivery.
* Administration of opioids in the 4 hours before study enrollment.
* Administration of IV magnesium sulfate within the last 24 hours.
* Diabetes mellitus (Type I and II).
* Neurocardiogenic signs or symptoms (e.g., dizziness, lightheadedness, bradycardia, and syncope) during IV cannulation.
* Cervical dilation \>6 cm (if in labor).
* BMI ≥ 35.
* Spinal anesthesia.
* Chronic pain patients.
* Opioid use disorder
* Patient with intrauterine fetal demise
* Prisoners.