///2012 Abstract Details
2012 Abstract Details2019-08-02T19:38:42-05:00

An Epidural Depth Equation prior to Ultrasound Visualization in Obese Parturients by Resident Trainees Increases Epidural Catheter Success Rate as Measured by Less Attempts and Site Placements

Abstract Number: TW-5
Abstract Type: Original Research

Manuel C. Vallejo MD, DMD1 ; Anthony Fabio PhD2; Amy L. Phelps PhD3; Fatima Zahir MBBS4; Olajide O. Kowe MBBS5; Fenny Anthikad MBBS6

Background: Morbidly obese parturients have a higher epidural analgesia failure rate. Morbidity and mortality are significant risk factors in obese parturients. Placement of a well functioning epidural catheter is crucial. Ultrasound (US) to assist in epidural catheter placement has been shown to reduce epidural catheter failure rates and placement attempts. Even with the use of US, the increased amount of subcutaneous tissue and fat in the obese parturient can pose a significant challenge to successful catheter placement. The purpose is to determine if the use of an epidural depth equation (EDE) prior to US visualization results in less attempts, less lumbar site placements in morbidly obese parturients receiving labor epidural analgesia (LEA) by resident trainees compared to traditional technique and US only.

Methods: A cohort of obese parturients (BMI > 32 kg/m2) having had EDE plus US visualization was compared to a cohort of US only and traditional epidural technique. In the US only and EDE + US groups, the primary investigator (MV) calculated epidural distance using EDE (Epidural Depth (cm) = 6.63 – [0.07 x Ht (in)] + [0.02 x Wt (lbs)]), performed US measurements (transverse and midline longitudinal views), and informed the trainee the results of the calculated/estimated distances to the epidural space before needle insertion. Data reported as mean ± SD, median with range in parenthesis. Bivariate analysis was used to assess differences between possible confounders, and analyzed using t-test or Chi-square. Multivariate logistic regression was used to adjust for BMI, gestational age, gravidy, parity, cervical dilation, and VAS pain. A successful attempt or placement was defined as equal to 1, failure ≥ 1. P < 0.05 was significant.

Results: Demographic data presented in Table. EDE + US group had a larger BMI with increased success on the 1st attempt and 1 site lumbar placement. After adjusting for confounders (age, gestation, gravidy, parity, cervical dilation and VAS pain), multivariate logistic regression revealed US + EDE technique was more likely to have a successful 1st attempt (OR, 3.1; 95% CI 1.81-5.28, P< 0.001) and one site placement (OR, 6.5, 95% CI 3.10-13.50, P< 0.001) compared to the US only and traditional technique.

Conclusion: The use of an epidural depth equation (EDE) prior to US visualization results in increased success on the 1st epidural attempt and fewer lumbar site placements in obese parturients by resident trainees.

SOAP 2012