Pencil-point Needle Bevel Direction Influences ED50 of Isobaric Ropivacaine With Fentanyl in Spinal Anesthesia for Cesarean Delivery: A Prospective, Double-blind Sequential Allocation Study. Issue 2 (June 2017) - Stroumpoulis, K.
Abstract : ( Int J Obstet Anesth . 2015;24:225–229) There are few studies on the effect of bevel direction on the quality of spinal anesthesia when using a pencil-point spinal needle. The authors' clinical experience suggested a lower local anesthetic dose was needed to achieve satisfactory anesthesia for cesarean delivery (CD) when the distal aperture of a Whitacre spinal needle was oriented cephalad. Their present double-blind study used the minimum local analgesic dose model to investigate if the median effective dose (ED50) of isobaric ropivacaine for CD spinal anesthesia varied based on the distal aperture direction of a Whitacre pencil-point needle.