Skin-epidural distance in children.

The skin-epidural distance was measured in 274 children to assess the usefulness of 1 mm.kg-1 as a guideline. Children aged between 2 days and 16 years, weighing between 2 and 43 kg were investigated. Lumbar epidurals were performed under general anaesthesia using a midline approach in the L3-4 interspace with the patient in the lateral position. Good correlation between skin-epidural distance and age and weight was demonstrated. No statistical difference was shown when plotting the best fit regression line: skin-epidural distance (mm) = 0.8 weight (kg) + 3.93 (R2 = 0.74) and its 95% confidence limits and skin-epidural distance (mm) = weight (kg) for children between 6 months and 10 years. Poor correlation was noted below 6 months (n = 22) and over 10 years (n = 19). No dural puncture or bloody tap occurred. One mm.kg-1 body weight was shown to be a useful guideline for children between 6 months and 10 years of age.