Hasan et al developed two equations for predicting the depth of the epidural space in European children. The authors are from the Hospitals for Sick Children in London.

Patient selection: 586 infants and children up to 14 years and 60 kilograms


Procedure: lumbar epidural block using an 18 gauge (body weight > 10 kg) or 19 gauge (body weight < 10 kg) epidural needle inserted into the midline



(1) age of the patient in years (this appears to be a continuous variable expressed with decimal fraction based on Figure 1 on page 1086)

(2) weight of the patient in kilograms


depth in cm =

= (0.15 * (age in years)) + 1


depth in cm =

= (0.05 * (weight in kilograms)) + 0.8



• I am not sure what the impact of obesity would be.

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