Predictors of difficult epidural placement in pregnant women: A trainees' perspective

Epidural analgesia is believed to be the most difficult technique to learn for a trainee. The reason for this is not only inexperience of the provider and the complexity of the technique but also patient factors like obesity, spinal deformity and others which makes the epidural placement difficult. The aim of this study was to evaluate some of the common risk factors for difficult epidural placement as perceived by the anesthesia providers during training, with varying level of experience.

This prospective observational study includes patients who received epidural placement for labor analgesia. Data recorded on these patients included age, height, weight, body mass index (BMI), ease of palpation of the spinous process, level of epidural placement, number of attempts, time taken for epidural placement and experience of the provider. The association between the variables were assessed using logistic regression for first attempt success and Cox proportional hazard ratio for time to epidural placement.

A total of 373 patients received epidural placement for labor analgesia. The mean BMI at the time of placement was 34. The first attempt success rate for the placement of epidural was 67% (n = 273). Women with well palpable spinous process were 3.3 times more likely to have a successful first attempt placement irrespective of the provider experience or BMI [3.39 (1.77-6.51), P < 0.001]. The time to placement was shorter in patients with good anatomical landmarks [1.58 (1.20-2.07), P < 0.001) and when performed by a trainee who had performed a minimum of 20 epidural procedures [1.57 (1.26-1.94), P < 0.001).

Inability to palpate the spinous process contributes to multiple attempts at epidural placement when performed by a trainee.