Nerve Stimulation with Ultrasound: The Clinical Benefits

Michael L. Kentor, MD, Pittsburgh

AT UPMC SOUTHSIDE, we always use a combination of nerve stimulation and ultrasound for peripheral nerve blocks. In our teaching hospital, where we deliver thousands of blocks each year, we find this "belt and suspenders" approach results in superior success rates, fewer complications, better reimbursement and savings on drug costs. In four years of using this approach, we've documented significant improvements for our patients, residents and our facility. They include:

  • Increased success rates. When we used stimulation only, we succeeded in the vast majority of cases and most of our blocks went smoothly. However, patients with more challenging anatomy could stop us cold. Obese patients, for instance, can exhibit nerve movement on respiration. Because we can now visualize the anatomy and double check our needle tip location with stimulation, we are able to maintain correct needle placement. Our success rate has risen from about 90 percent to better than 97 percent.[1]
  • Complication avoidance. Our complications were very low with stimulation alone — a study we did showed that we experienced seizures and nerve injuries in eight of 3,290 cases — less than .25 percent. But in 2,146 cases using both technologies, examined in the same study, we experienced no complications.[2]
  • Improved economics. In our area, many insurers offer reimbursement for ultrasound use. Using ultrasound also saves costs, because ultrasound enables us to use less local anesthetic. When we used stimulation alone, we typically injected 40 cc of ropivacaine for an interscalene block. Now that we can actually visualize the spread of anesthetic, we use only 20-30 cc. We think this is also better care. We are still likely getting some degree of phrenic nerve paresis, but we seem to hear fewer complaints of "shortness of breath."
  • Better education. Viewing the anatomy "live" is a tremendous training aid for residents. Incidentally, it's also a great training aid for patients; we offer them the opportunity to watch their own blocks and most do!

We rotate between 25 - 30 anesthesia residents through our facility each year. All receive training in stimulation with ultrasound. Many other residencies use a similar approach. The influx of new physicians trained in this way, together with the superiority of the technique, may mean that ultrasound + stimulation will be the standard of care in the near future. In the meantime, our residents benefit from exposure to as many tools as possible. Our hope is that when they leave our training, they have the skills to adapt to the needs of their new facility.

Reference
1. Orebaugh SL, Williams BA, Kentor ML, et al. Interscalene block using ultrasound guidance: impact of experience on resident performance. Acta Anaesthesiol Scand. 2009 Nov;53(10):1268-74. .
2. Orebaugh SL, Williams BA, Vallejo M, Kentor ML. Adverse outcomes associated with stimulator-based peripheral nerve blocks with versus without ultrasound visualization. Reg Anesth Pain Med. 2009 May-Jun;34(3):251-5

Dr. Kentor is an associate professor at the University of Pittsburgh and Chief Anesthesiologist at UPMC Southside Hospital.


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