TAP blocks have been around a long time, but have really become increasingly popular over the last 10 years in the U.S. I first learned and utilized these regional techniques while in the Army. At that time, we typically only used them for lower abdominal surgeries such as hysterectomies and prostatectomies. We would perform ultrasound-guided classic TAP blocks, providing analgesia from T10-L1, blocking somatic pain. Visceral pain isn’t covered by these blocks, so epidural analgesia was still considered the gold standard.
As time has marched on, both classic and subcostal TAP blocks have become vogue. Whereas classic TAP blocks are performed midway between the lower costal margin and the iliac crest, subcostal TAP blocks are performed higher up on the abdominal wall, just beneath the rib cage. These blocks provide analgesia from T7-T10. When you do bilateral subcostal and classic TAP blocks, you can quickly and safely provide excellent blockade from T7-L1.
The beauty of TAP blocks is that they don’t cause a drop in blood pressure from a sympathectomy, so often seen with epidural analgesia. Also, you don’t have to be concerned about anti-coagulants and platelet counts to the same extent as you do when considering neuraxial(epidural) blocks. Another plus is that narcotics aren’t utilized with these blocks, just local anesthetic, plus or minus an additive such as dexamethasone or clonidine. The benefit of not having neuraxial narcotics is no respiratory depression, no nausea, no itching and no constipation from your analgesic technique.
We now routinely utilize subcostal and classic TAP blocks for all types of abdominal surgeries, such as open cholecystectomies, exploratory laparotomies and complex hernia repairs. Several of our general surgeons have been greatly impressed by the quality of analgesia they’re seeing in their patients after we’ve done these blocks. Our PACU nurses are noticing how much more comfortable the patients are, and how they emerge quicker and crisper after having required less intra-operative anesthetics.
These techniques provide pre-emptive analgesia, they allow reduced intra-operative volatile agent and narcotic usage, and provide post-operative analgesia that lasts for up to 24 hours. As for type and amount of local anesthetic used, it depends on the age and size of the patient, the type/location of the surgery and how many injections we’re doing. Volumes range from 10-30 mL at each site. The quality of the spread/hydrodissection you see on ultrasound also can guide how much to give. We usually inject 0.5% bupivacaine or ropivacaine. You can also use 0.25% bupivacaine.
They are easy to learn and can be done in less than five minutes. A few weeks ago I did a unilateral subcostal TAP injection, and walked one of our CRNAs through her first classic TAP injection for a patient following an open cholecystectomy. The following day at 9:00 am, the patient had 0/10 pain, some 21 hours after we had done the blocks.
I think TAP blocks and TAP catheters will replace epidural catheters for abdominal surgeries over the next decade.
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