Epidural technique
intravascular or subarachnoid position
STERILE
The patient was positioned sitting on the bed to achieve an adequate exposition of the lumbar spine. Then, skin was cleaned with alcoholic clorhexidine and then a sterile field was prepared. L3/L4 space was identified by palpation through the Touffier’s line, and 4 mL of subcutaneous LA (lidocaine 2%) was administered in the puncture zone with a fine needle (23G). Tuohy’s needle (18G, 80 mm) was then introduced and fixed by supra and interspinous ligaments. The epidural space was then identified through the loss-of-resistance technique with a 10 mL low resistance syrinx filled with saline solution. An epidural catheter (closed tip with 3 lateral openings) was then introduced and a test dose consisting of 3 mL of 2% lidocaine + epinephrine 1: 200:000 was administered through the catheter to exclude intravascular or subarachnoid position of the catheter. The catheter was left with 3.5 cm of margin inside the epidural space.Each patient received randomly an epidural infusion consisting of levobupivacaine 0.0625% + fentanyl 2mcg/mL or ropivacaine 0,075% + fentanyl 2mcg/mL. The initial volume of the bolus varied depending on the height of the patient: patients smaller than 160 cm received 8 mL, between 160 and 170 cm received 10mL and taller than 170 cm received 12 mL. Then, a continuous infusion was programed, and the rate was defined again by the same distribution of patient’s height: 10, 12 and 15 mL/h respectively. Finally, a patient-controlled rescue bolus of 10 mL of the same infusion was available every time, with a closing time of 20 min and a maximum of 3 boluses per hour.