M-mode Ultrasonography for Epidural Catheter Identification and Confirmation of Correct Catheter Position

In France, 80% of women choose epidural analgesia for delivery and birth. The localization of the epidural space is classically achieved by loss of resistance to saline. This blind technique means the passage of the needle through the ligamentum flavum. However, epidural analgesia failure has been reported in 27-32% of cases.

Currently, lumbar neuraxial ultrasound has become a valuable tool facilitating the placement of an epidural catheter. Although lumbar neuraxial ultrasound has been the source of many studies, few have focused on its use to confirm the exact location of the epidural catheter in the epidural space.

Indeed, only 2 retrospective studies have described this strategy on cohorts with small numbers of adult patients. One demonstrated in a mixed population the possible localization of the epidural analgesia catheter using color Doppler (cD) mode (67.5% of cases) and M-mode (M-m) ultrasonography (M-m) (75%). Only one study identified the position of the epidural catheter in the obstetric context due to the cD mode ; with a low rate of visualization (37.1% of cases).

In the Pediatric and Obstetric Anesthesia-Resuscitation Department of the Necker-Enfants Malades Hospital, pre procedural lumbar neuraxial ultrasound for epidural anesthesia is a regular practice.

The objective of this study is to evaluate the ability of the M-m and cD mode to identify proper catheter placement in parturients in the delivery room.

Inclusion criteria

• Adult women admitted to the delivery room for a vaginal delivery with an epidural analgesia.
• Written informed consent.
• French speaking patient.

Exclusion criteria

• Patient with a contraindication to neuraxial analgesia.
• Visual Analogue Scale score >7 at epidural analgesia pose.
• No health insurance.