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

Epidural Pressure Waveform to Confirm Correct Positioning of the Epidural Needle in Laboring Pregnant Patients

Abstract Number: F-33
Abstract Type: Case Report/Case Series

Ilana Sebbag MD1 ; Indu Singh MD, FRCPC2; Fatemah Qasem MD3; Kevin Armstrong MD, FRCPC4

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

Methods: Written informed consent for case report was obtained from all patients. Patients were all ASA II and presented in the 1st stage of labor, cervical dilation of 4 cm. Case 1 - a 27-yr-old primigravida at 40 weeks gestational age (GA), initial pain Numeric Rating Scale (NRS) of 5. Case 2 - a 32-yr-old primigravida at 41 weeks GA, initial NRS of 8. Case 3 - a 29-yr-old multipara at 40 weeks GA, initial NRS of 6. For each case, standard monitoring was connected to the patient. An epidural anesthetic was then performed at the L3-4 level, using the LOR to saline technique. The needle was filled with 2-3 mL NaCl 0.9% and a high-pressure tubing extension leveled at L3-4 was connected to the needle and the pressure was transduced. Epidural pressure waveform was recorded for all patients at both a “rest” state (in between uterine contractions) and at an “active” state (during a contraction). Epidural catheters were threaded and all patients received a loading dose of 8-10 mL 2% lidocaine. Thirty minutes later, block levels and patient satisfaction (NRS) were recorded.

Results: For cases 1 and 2, a clear epidural waveform and pressure readings were obtained during both the “rest” and “active” states. During the “active” phase, an elevation of the systolic component of the epidural pressure was noticed (4 mmHg for case1, 3 mmHg for case 2). At 30 minutes, both patients had a bilateral block (T10/T11 and NRS of 3 for case 1, T9/T11 and NRS of 1 for case 2). For case 3, we unable to obtain an epidural pressure waveform. At 30 min, she had an inadequate block (L1/L2, NRS remained at 6).

Discussion: The presence of an epidural pressure waveform correlated with an adequate bilateral block 30 min after epidural loading dose.The absence of a waveform on the 3rd case was associated with an inadequate block.

SOAP 2015