The Utility of Pre-procedure Ultrasound for Neuraxial Analgesia/Anesthesia in Obstetric Patients

Ultrasound has been in use for peripheral regional anesthesia for several years and is becoming more common. It is currently routinely used here at the University of Missouri. Ultrasound for neuraxial anesthesia, however, is less common and is only being done in a few centers.. There have been several case reports of its use in obstetric anesthesia for patients with prior spinal surgery or spinal deformity. There have been even few prospective randomized studies. While its use may have significant advantages, it is not yet clear what those advantages are and in whom it may be most beneficial. The investigators seek to answer the following questions regarding the use of preprocedure ultrasound for neuraxial analgesia/anesthesia in obstetric patients:

• Are there benefits to the use of pre procedure ultrasound for neuraxial analgesia/anesthesia?
• If so, what are the benefits?
• If measurable, to what extent does the patient benefit?
• Do all patients benefit or only a specific subgroup?
• Is there a "cost" to the use of pre procedure ultrasound, i.e. extra time needed to perform the ultrasound exam vs a "savings" with the use of pre procedure ultrasound, i.e., less time to perform the epidural analgesic or spinal anesthetic as a direct result of the use of ultrasound?
• In particular the investigators hypothesize that in patients whose spinal landmarks are not palpable or are barely palpable, ultrasound will be found to be beneficial as determined by metrics described below (see item #6). In patients whose landmarks are prominent or easily palpable pre procedure ultrasound will not be of significant benefit.