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Bridalveil Falls - photo by JoAnn Sturman
Ten members of the department discussed methods to refine delivery of regional anesthesia, taking into account both literature sources and anecdotal experiences.
Multimodal Therapeutic Options for Total Joint Surgery:
Since earlier development of protocols, the number of beneficial medications and experiences with them have expanded. The following recommendations are supported by the academic literature:
Lyrica (Pregabalin) 300 mg in holding + 150mg BID. At age 70 reduce to half dose. Pregabalin was chosen over gabapentin due to its increased lipid solubility and stronger support from the medical literature; the cost is only marginally more expensive ($3 vs. $1).
Celebrex 200 mg pre op then QD
Decadron 10 mg IV in OR
Ketamine/propofol infusions for IV sedation. Doses administered by department members vary from Propofol 2-5mg/ Ketamine 1mg. The cumulative target dose is at least 1mg/kg given over the duration of the case. Propofol doses are reduced, and there are some long term benefits for RX of chronic pain. Recommend giving glycopyrroate 0.2 mg before administration to reduce salivation.
Tylenlol 1gm IV Q 6 hours for one day. Begin at beginning of case with 4 doses total. This may be the most difficult aspect to incorporate into the protocol, since patients frequently are taking oral analgesics which contain acetaminophen. In the absence of liver disease the FDA has established 4gm as the maximum daily dose, and some conjecture this limit soon will be revised downward to 3 gm QD. A more appropriate role of IV acetaminophen may be reserved for rescue pain situations.
Upper extremity
ISB is the gold standard for block efficacy. Performing an ISB is the morning and giving a local anesthetic which lasts on average 16 hours makes an uncomfortable night for the patient. Since prolonged block duration is the goal for post op pain RX, 0.5% bupivacaine is preferable to .5% ropivacaine. The former is a less expensive option, as well. It appears adding dexamethasone 4-8 mg will extend block duration with the effect more pronounced with ropivacaine than bupivacaine. Adding buprenorphine 300 ug to bupivacaine is another option for prolonging block duration.
SCB has not enjoyed the same rate of success as ISB. This may be due to variations in technique. The most consistent results require injections in at least two locations. First, position the needle near the first rib just inferior to the brachial plexus. Inject half of the local to push the brachial plexus upward, then approach superiorly and inject the other half within the bundle.
ICB is a more difficult block due to the steep angle of the needle, however, it is very useful in hand and forearm surgery and completely spares the phrenic nerve. Hydrodissection is useful for gauging the location of the needle in larger patients. Depositing the bulk of the local between the 3 and 6 o’clock position of the axillary artery provides an excellent block.
Abdomen
Subcostal TAP is useful for surgery above the umbilicus.
Inferior TAP is indicated for lower abdomen procedures.
Both of these blocks are compartment blocks and rely on volume. The block does not ensure surgical anesthesia, but reduces general anesthesia requirements and provides post op pain relief. Procedures which involve both sides of the abdomen require bilateral blocks–30 cc of bupivacaine 0.25 % on each side is optimum. TAP blocks have no effect on the viscera. The primary benefit is to the abdomen wall. Complete analgesia is difficult to obtain, but pain scores are more typically 2-3 in the PACU.
Spine
Due to extensive post op pain, intrathecal narcotics have an indication. Their use depends on surgeon preference and concerns like CSF leak and the ability to assess lower limb function immediately after surgery. It would be better to avoid local anesthetics in the block to prevent confusion during the post op assessment.
Hip
THA patients fare well with SAB and IT narcotics. Revising protocols should only improve this standard.
FICB is useful for hip fractures; often elderly patients require no narcotics in OR and PACU. The posterior capsule of the hip is not covered by this block. FICB is a compartment block where volume is key. 40cc of .25% bupivacaine is usually adequate. Again post op pain RX rather than surgical anesthesia is the goal.
Knee
Levels of satisfaction with post op RX relief in TKA have not achieved the rates of THA. Refining protocols hold promise. The department is currently evaluating the efficacy of the saphenous nerve block in the adductor canal to supplement SAB with IT narcotics. Preliminary data is encouraging, but more cases are required to provide an acceptable patient representation.
Due to the volume of local anesthesia needed in ACL surgery for both femoral and sciatic blocks, lower concentrations and higher volumes are warranted. 30cc of .25% bupivacaine at each site may be needed to insure adequate blocks.
Foot and Ankle
The sciatic nerve block at the popliteal has the worst rates of success within the department and nationally. The block takes more time to set up and local must be deposited to provide the classic doughnut sign. When the block is performed in the supine position, the sciatic nerve is not stretched, and one must be careful to place the block sufficiently high in the leg. The 7 cm point above the popliteal crease which is used in the prone position to mark the bifurcation of the nerves is not accurate when the leg is bent in the supine position. One may inadvertently block too low and only anesthetize the peroneal nerve–probably a common cause of block failure due to sparing of the tibial nerve.
If the sciatic/saphenous nerve block is adequate, it should provide surgical anesthesia and allow the patient to be carried on very low doses of gas (much like a successful ISB). Any bump in the vital signs during the procedure should alert one that the block is spotty and to ask the surgeon to supplement the block at the conclusion of the case.
Miscellaneous:
Most itching due to IT narcotics is tolerable, but for those with intractable symptoms it is a problem. With the inability to obtain Nubain, administering buprenorphine 150ug IV Q 6 hours is a suitable alternative for rescue RX.
Patient controlled labor epidurals: In order to avoid overly high levels, the lock out can be extended longer than 15 minutes. A 20 minute lock out for the 5 cc bolus with a 10cc continuous allows the patient to administer the full 25 cc/hour, if required. Baseline rates and bolus doses will be reevaluated as the program progresses.
Due to heightened concerns about lower extremity blocks and the increased risk of falling, some institutions place a warning sign on the patient’s affected extremity prior to discharge from the recovery room. This services as a graphic and reinforcing warning about the added concerns of ambulating on a weak leg. A sample can be found on the Neuraxiom website.
Panorama from Nevada Falls - photo by JoAnn Sturman
