Young children exposed to general anesthesics were twice as likely to be diagnosed with developmental or behavioral disorders, according to a study performed by researchers at Columbia University.

During a four-year period, Lena S. Sun, MD, a professor of anesthesiology and pediatrics, and her colleagues analyzed clinical data of children under three years old who were exposed to general anesthesia as part of hernia repair operations. Researchers compared the data with that of 5,000 children who had never been exposed to anesthesia. The results correlate with recent animal studies that suggest general anesthesia agents may have neurotoxic effects on young brains.

Dr. Sun presented her findings during a panel discussion at the American Society of Anesthesiologists' annual meeting in Orlando last week. In a press release, Dr. Sun says she hopes the Columbia study represents a starting point for further study of the developmental effects of general anesthesia on children.

"This current analysis only examined two or three years of post-exposure data," she says. Plus, the children who were exposed to anesthesia were all Medicaid patients. "One limitation of the data is that the demographic factors of this group that may vary from the general population."

Kent Steinriede

Two recent studies exploring the risk factors for post-operative delirium in older patients may help healthcare providers develop better pre-operative interventions to prevent this costly and relatively common complication of general anesthesia.

In a study presented at the American Society of Anesthesiologists' annual meeting last week, researchers from Duke University's School of Medicine screened 100 patients aged 50 years and older for depression and administered five pre-operative tests that measured their cognitive, concentration and self-monitoring abilities. After undergoing non-cardiac surgery with general anesthesia, 16 percent of the patients experienced delirium. The researchers, led by Terri Monk, MD, found two short tests - the Geriatric Depression Scale short form and the Trails B portion of the cognitive Trail Making Test - to be the most reliable predictors of post-op delirium among the sample population.

According to an press release, Dr. Monk and her team consider their study to be "an important first step in developing a practical and predictable screening tool that will help identify at-risk patients for pre-operative interventions" against post-op delirium. For example, Dr. Monk says future research may reveal that treating elderly patients for depression before elective surgery could reduce their risk of experiencing delirium.

Last month, a separate study published in the Canadian Medical Association Journal revealed another possible risk factor for delirium: statin usage. Researchers found that older adults who take the cholesterol-lowering drugs have a 28 percent greater risk of experiencing delirium after surgery than those who don't take statins. The authors of that study recommended temporarily halting the use of statins before surgery to help prevent post-op delirium in elderly patients.

Irene Tsikitas

An educational guide on the combined use of ultrasound with nerve stimulation as a best practice for nerve location in regional anesthesia is available from medical manufacturer B. Braun.

Dual Guidance: A Multimodal Approach to Nerve Location aims to transform regional anesthesia into a more objective and reproducible discipline than it has been in the past. To obtain a copy, e-mail the company at dualguidance.us@bbraun.com.

"A dual guidance technique affords the anesthesiologist an unprecedented level of understanding and respect for the mysterious needle-to-nerve interaction," says Richard Brull, MD, assistant professor and director of the regional Anesthesia Fellowship Program at the University of Toronto, in the introduction. "Most importantly, it affords the anesthesiologist a higher level of confidence and comfort by drawing on two objective end points - real-time visualization of local anesthetic spread and minimum stimulating threshold current - to predict the likelihood of block success and, possibly, minimize block-related complications."

Nerve stimulation has long been the gold standard for nerve location when performing peripheral nerve blocks, stimulating the nerve and causing the target muscle to twitch. More recently, high-frequency ultrasound imaging has increasingly gained ground as a supplementary or complementary modality, as it lets the anesthesia provider see the nerve and the needle as well as the spread of local anesthesia. Each method offers distinct advantages and limitations.

"It is important for the clinical practitioner to be open to the use of either technique or the combination of the two," says guide contributor William Urmey, MD, attending anesthesiologist at the Hospital for Special Surgery and associate professor of clinical anesthesiology at Weill Cornell Medical College in New York, N.Y. "The use of ultrasound guidance is in its infancy, and we can only hope that it achieves the same high success rate and low complication rate associated with nerve stimulation. Thus far, it has shown great promise."

Dan O'Connor