Epidural Catheter Placement in Morbidly Obese Parturients with the Use of an Epidural Depth Equation prior to Ultrasound Visualization

Sukhdip Singh,Manuel C Vallejo,Tanmay H Shah,Manasi H Badve,Neera Sah,Keith M Wirth,Amy L Phelps

doi:10.1155/2013/695209

Abstract

Background. Previously, Balki determined the Pearson correlation coefficient with the use of ultrasound (US) was 0.85 in morbidly obese parturients. We aimed to determine if the use of the epidural depth equation (EDE) in conjunction with US can provide better clinical correlation in estimating the distance from the skin to the epidural space in morbidly obese parturients. Methods. One hundred sixty morbidly obese (≥40 kg/m2) parturients requesting labor epidural analgesia were enrolled. Before epidural catheter placement, EDE was used to estimate depth to the epidural space. This estimation was used to help visualize the epidural space with the transverse and midline longitudinal US views and to measure depth to epidural space. The measured epidural depth was made available to the resident trainee before needle insertion. Actual needle depth (ND) to the epidural space was recorded. Results. Pearson's correlation coefficients comparing actual (ND) versus US estimated depth to the epidural space in the longitudinal median and transverse planes were 0.905 (95% CI: 0.873 to 0.929) and 0.899 (95% CI: 0.865 to 0.925), respectively. Conclusion. Use of the epidural depth equation (EDE) in conjunction with the longitudinal and transverse US views results in better clinical correlation than with the use of US alone.

Highlights

The prevalence of obesity has grown to epidemic proportions over the past 20 years, with estimates of at least 1.6 billion overweight and 400 million obese adults worldwide [1]
We investigated the use of US for epidural catheter placement in laboring parturients, found high correlation between estimated US depth and actual needle depth (ND); (Pearson’s correlation coefficient ≥0.91) [16], and derived an epidural depth equation (EDE) using stepwise multivariate linear regression for predicting the distance from the skin to the epidural space in the lower lumbar intervertebral area
With local investigative review board approval and informed verbal and written consent, morbidly obese parturients (BMI ≥ 40 kg/m2) who requested labor epidural analgesia or scheduled for elective Cesarean section were recruited into the study

Summary

Introduction

The prevalence of obesity has grown to epidemic proportions over the past 20 years, with estimates of at least 1.6 billion overweight and 400 million obese adults worldwide [1]. Balki determined the Pearson correlation coefficient with the use of ultrasound (US) was 0.85 in morbidly obese parturients. We aimed to determine if the use of the epidural depth equation (EDE) in conjunction with US can provide better clinical correlation in estimating the distance from the skin to the epidural space in morbidly obese parturients. EDE was used to estimate depth to the epidural space. Pearson’s correlation coefficients comparing actual (ND) versus US estimated depth to the epidural space in the longitudinal median and transverse planes were 0.905 (95% CI: 0.873 to 0.929) and 0.899 (95% CI: 0.865 to 0.925), respectively. Use of the epidural depth equation (EDE) in conjunction with the longitudinal and transverse US views results in better clinical correlation than with the use of US alone

Objectives

Methods

Conclusion