Which neuraxial technique uses a catheter for incremental dosing?

• A. Spinal anesthesia
• B. Intrathecal anesthesia
• C. Epidural anesthesia
• D. Caudal block

Answer: (C)

Incremental dosing through an indwelling catheter is the defining feature here. Epidural anesthesia uses a catheter placed in the epidural space, allowing repeated small injections or a continuous infusion of local anesthetic (often with opioids or adjuvants) to titrate the sensory level and duration of the block. This setup makes it possible to adjust anesthesia or analgesia as needed throughout a procedure or into the postoperative period.

Spinal (intrathecal) anesthesia delivers medication into the subarachnoid space and is typically a single-shot, with a fixed duration; while its effects can be extended only by re-puncture, it does not rely on a catheter for routine incremental dosing. The caudal block accesses the epidural space via the sacral hiatus and is usually a single-shot technique in many settings, particularly pediatrics, though a catheter can be used in some cases, it is not the classic method emphasized for incremental dosing. The epidural approach is the one inherently designed for catheter-based, titratable dosing.