Pulsatile Pressure Waveform to Confirm Correct Placement of the Epidural in Laboring Patients

Study Overview
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Brief Summary
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Epidural analgesia is highly effective for labor pain relief and is widely chosen by pregnant patients. However, placement of the epidural needle can be challenging in pregnant patients due to lax tissue ligaments and edema so that the traditional loss of resistance method (LOR) used to find the space may be subtle leading to retries which may delay onset of analgesia as well as increase the risk of complications. The ability to transduce a pulsatile pressure waveform from epidural needles placed in non-laboring patients correlates highly with successful placement of the epidural needle. We wish to evaluate the efficacy of obtaining a pulsatile pressure waveform with correct epidural needle placement in laboring women.

Detailed Description
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Patients requesting epidural labor analgesia will be eligible for recruitment. After written informed consent is obtained, placement of monitors and aseptic technique, the 17G epidural needle will be placed using the loss of resistance (LOR) technique to air or saline at the lumbar level chosen by the anesthesiologist. When LOR occurs, the needle will then be filled with 2 mL NaCl 0.9% from that syringe and the pressure monitoring accessory will be connected to the needle. The second investigator will then connect the high pressure tubing to the acessory without touching it, and the pressure will be zeroed at level of the needle insertion. Pressure will then be transduced and the waveform, recorded. An epidural catheter (SIMS Portex) will then be passed through the needle and advanced 5 cm beyond the tip of the epidural needle. After securing the epidural catheter in place, the patient will be placed on the lateral position. The catheter will then be filled NaCl 0.9% from a syringe and a high-pressure tubing extension leveled at the spine level will be connected to the catheter and the pressure will be transduced and recorded. Data recorded will include 2 parameters: 1) The presence or absence of a pulsatile waveform, and 2) The actual pressure read at the epidural space, in mmHg. Those readings will be obtained in 2 distinct moments: at a  rest state, meaning during an interval between contractions, and at an active state, during the first contraction after the epidural catheter is placed. A test dose of 3 mL of 2% lidocaine with epinephrine1:200.000 will then be given to exclude potential spinal or intravascular injection. After 3 minutes, a loading dose of 10mL of 0,125% bupivacaine will be given for labor analgesia and the presence or absence of a bilateral sensorial block at T10 or higher at 30 min will be assessed.

Official Title
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Efficacy of the Presence of a Pulsatile Pressure Waveform to Confirm Correct Placement of the Epidural Needle and Catheter in Laboring Pregnant Patients: a Feasibility Study

Conditions
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Analgesia, Epidural

Intervention / Treatment
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* Procedure: Epidural Pressure Waveform


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female Patients ASA I-III Term Pregnancy (>37 weeks) 18 years or older Early Labour (<6 cm of cervical dilation) BMI<40 Exclusion Criteria: Any contraindication to epidural analgesia placement (coagulopathy, sepsis, infection at site, increased ICP, hypovolemia, unstable ischemic heart disease, unstable neurologic disease, severe aortic stenosis, prior spinal surgery, LA allergy) Serious concern for maternal or fetal wellfare.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Epidural Pressure Waveform<br>Study Population: Term pregnancy in labour 18 years of age or older. | Procedure: Epidural Pressure Waveform<br>* When loss of resistance occurs, a high-pressure tubing extension will be connected to the needle and the pressure will be transduced and the waveform, recorded. An epidural catheter will then be passed through the needle and connected to a high-pressure tubing extension and the pressure will be transduced and recorded. A test dose of 3 mL of 2% lidocaine with epinephrine 1:200.000 will then be given to exclude potential spinal or intravascular injection. After 3 minutes, a loading dose of 10 mL of 0,125% bupivacaine will be given for labor analgesia and the presence or absence of a bilateral sensorial block at T10 or higher at 30 min will be assessed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Epidural Needle Insertion Success | Presence of a pulsatile pressure waveform at the epidural needle as a good predictor of a successful epidural block 30 min after local anesthetic injection | 30 min after loading dose | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Epidural Pressure in mmHg | Epidural pressures during uterine contractions and in-between contractions in mmHg | 5 min after epidural needle insertion | 
| Epidural Waveform at the Catheter | Presence or absence of an epidural waveform measured through the epidural catheter right after insertion | Immediately after epidural catheter insertion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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epidural, labor analgesia, pressure monitoring