Utility of Ultrasound in Identification of Midline and Placement of Epidural in Severely Obese Parturients

The use of ultrasound has expanded into many areas of medicine including the identification of bony landmarks to facilitate epidural placement in obstetric anesthesia. Using ultrasound for epidural placement has become popular over the last decade with several studies being published on the topic. The likely increase in popularity for ultrasound use in the obstetric population is the need to more reliably locate bony landmarks as the traditional palpation technique has been shown to be an inaccurate way to accomplish this. Given the fact that the long-taught palpation technique can be inaccurate and studies have validated the use of ultrasound for epidural placement, ultrasound technique is routinely taught by the obstetric anesthesiologists to the anesthesiology residents at the University of Alabama at Birmingham (UAB). Also, since both techniques are considered standard practice at UAB, anesthesia providers (residents, fellows, and faculty) are free to choose either technique to locate bony structures of the back prior to epidural placement. Since no current study has specifically addressed its use in the obese pregnant patient, the investigators would like to validate its use in this population.

In this study, investigators will evaluate the use of ultrasound in the obese population to determine if its use will decrease the time it takes to place the epidural and number of attempts required when compared to the traditional palpation technique. The study will also determine the success rate of epidural placement in both the palpation and ultrasound groups.

Inclusion criteria

• patient request for a labor epidural
• BMI≥35

Exclusion criteria

• BMI<35
• patient refusal of a labor epidural
• coagulopathy
• platelets<80,000
• prior spine procedure or instrumentation
• a diagnosis of scoliosis
• an intracranial or spinal mass