“…Because no test meets this standard, 9,10 anesthesiologists rely on a variety of different testing combinations and dosing strategies to avoid patient harm. 2,11,12 Aspiration of the catheter detects the majority, but not all, intravascular and intrathecal epidural catheters. In obstetrics, 5-8% of epidural catheters enter a vein during initial insertion, [13][14][15][16][17] and 0.04-0.14% enter the subarachnoid space.…”