Catheter Based Blocks

Talking about nerve blocks for post-operative pain management is fine and dandy, but one limitation is the duration of action. For a single injection, our longest acting local anesthetics only last for half a day. In fact, this can cause problems with patients who get a nerve block in the early afternoon; they go home happy, go to bed pain free, and then wake up in the middle of the night with excruciating discomfort when the block wears off. When I talk to patients about nerve blocks, I have to set up expectations on when the block will recede so that patients can start taking oral pain medications to smooth the transition.

However, in some cases, we can leave a small catheter near the nerve to deliver local anesthetic continuously. We no longer have to worry about the limited duration of a single injection. Placing the catheter is a little more challenging and a lot more time consuming than a quick injection, but when it is effective, it's very satisfying. For inpatients, we visit them every day to make adjustments on their local anesthetic infusion. We try to balance pain control with muscle weakness; the more numbing a patient gets, the greater the effect on the motor function. To optimize physical therapy, a patient needs to be able to move with minimum pain. For outpatients, we can send someone home with an automatic infusion system. The catheter is connected to a disposable bulb filled with medication. We adjust the rate of delivery before sending the patient home. When the medication runs out, the patient simply takes out the soft flexible plastic catheter and throws it all away. I think this has made outpatient pain management much easier as surgical discomfort can be managed outside the hospital.