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Vital Signs

Patients go home quicker, in less pain, with new technique

Numbing a specific part of a patient's body for surgery or pain relief has always been tricky. For decades, anesthesiologists have had to rely on knowledge of anatomy, sense of touch, and a little bit of luck to inject painkillers in the right region.

As a result, regional anesthesia was a talent few mastered. All doctors could do was "assume just normal anatomy," says anesthesiologist Brian Sites, M.D. "If you had multiple sticks or if you hit something you weren't supposed to, it was acceptable."

Blocks: But that standard of care is rapidly becoming a thing of the past, thanks to an emerging procedure called ultrasoundguided nerve blocks. DHMC's Regional Anesthesia Program, under Sites's leadership, has been performing the procedure since December 2003, and Dartmouth is one of only six places worldwide doing research on it. Highresolution ultrasound imaging lets doctors see exactly where they're inserting their needles. They can stay away from hazards, such as major blood vessels, and get very close to the nerves whose signaling they wish to block—allowing them to use lower doses of the anesthetic.

The technique can also be used in conjunction with general anesthesia. "When we do that, it allows us to use a lot less of the general anesthesia," says Sites. Vomiting and nausea from general anesthesia are common obstacles to postoperative patients going home. So those who have nerve blocks not only have less pain but get home sooner.

In the year since DHMC began offering ultrasound-guided nerve blocks, nearly 1,500 have been performed—most of them for orthopaedic procedures. Orthopaedic surgery, says Sites, is "one of the most painful procedures to recover from." But with the new technique, "we can anesthetize these nerves for longacting pain control."


Sites, by looking at an ultrasound image, can now anesthetize just the right nerve.

The idea of using ultrasound technology with nerve blocks has been around since the late 1970s. But it's only in the last five years that ultrasound equipment has been affordable, compact, and sophisticated enough to image neuroanatomy. In the past, regional anesthesia was "hard enough that few experts developed," says Sites. "You'd go to these national meetings and they would go through these very complicated, convoluted ways of putting the needle in and feeling these very subtle clicks and pops in the patient. Only a few people ever got good at it."

Sites recently gave a talk himself at a national meeting, about DHMC's nerve block program. Afterwards, "I was mobbed like at a rock concert," he chuckles. But sometimes when he gives such presentations, private-practice anesthesiologists will complain about the cost of the equipment. But, counters Sites, the same case was made decades ago against blood-pressure cuffs. "That argument just doesn't stand when you have superior technology," he maintains.

Proficient: To address the concerns of old-school anesthesiologists worried about learning a new technique, Sites did a study to determine how quickly the procedure could be taught. Ten anesthesia residents with zero experience using ultrasound were shown a 10-minute slide presentation on performing ultrasoundguided nerve blocks. The

residents then used the equipment on simulated human tissue. After three attempts, they were doing quite well. By their sixth try, all errors were eliminated. The results, published in the November 2004 issue of Regional Anesthesia and Pain Medicine, show that an anesthesiologist can become proficient at performing ultrasoundguided nerve blocks after only 40 minutes of training.

Other research endeavors of the Regional Anesthesia Program include determining the best ways to insert needles and adjust image quality, and describing what various nerves look like, because "a lot of these nerves haven't really been described from an ultrasound standpoint," explains Sites.

The research, combined with increasing patient demand for ultrasound-guided nerve blocks, is giving DHMC anesthesiology residents a big leg up on their counterparts elsewhere. "They're averaging over 100 nerve blocks a month," says Sites. A resident who does 80 nerve blocks during an entire residency, he explains, is "going to be like 90th percentile. So we're off the charts."

In the past, only more senior residents were allowed to perform nerve blocks. But now, with ultrasound, even first-years at DHMC can learn the procedure. "When I watch a resident put a needle into a patient, and I'm watching the needle and I'm watching the target, I feel good. I know how to make suggestions. I know how to control that experience. Whereas before, you couldn't feel what the resident was feeling," says Sites. "I think this is a great teaching modality and merges that dilemma of how do you train a resident and how do you take care of a patient."

The next step for the program, he says, is the July 2005 start of a post-residency fellowship in regional anesthesia.

—Jennifer Durgin

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