What's Behind Post-Op Cognitive Decline?

Anesthesia alone isn't enough to cause cognitive decline in patients with dementia — rather, it's the combination of anesthesia and surgery that can trigger onset of the phenomenon, according to a study by researchers at the University of Pennsylvania's Perelman School of Medicine. What's more, they found the mice in the study didn't even need to be exhibiting symptoms of Alzheimer's disease for post-operative cognitive decline to occur.

Post-operative cognitive decline is the term for the commonly reported loss of cognitive abilities, usually in older adults, in the days to weeks after surgery. Some patients trace the onset of Alzheimer's symptoms to their procedures, according to experts.

In the study, the researchers exposed mice with human Alzheimer's disease genes to either anesthesia alone, or anesthesia and abdominal surgery. The activation of surgery-related brain inflammation resulted in significant cognitive impairment that persisted for at least 14 weeks post-op, as compared to mice receiving anesthesia alone. Neither surgery plus anesthesia nor anesthesia alone produced changes in subjects without the genes.

"In the mice, there was a clear and persistent decrement in learning and memory caused by surgery as compared with inhalational anesthesia — but only in the context of a brain made vulnerable by human Alzheimer-associated transgenes," says lead researcher Roderic Eckenhoff, MD, the Austin Lamont Professor of Anesthesia at Penn.

Stephanie Wasek

Duodenal Switch Better Than Gastric Bypass?

The duodenal switch bariatric procedure results in more weight loss and better control over co-existing illnesses than gastric bypass does, according to a study published in the September issue of Archives of Surgery.

Researchers at Madigan Army Medical Center in Fort Lewis, Wash., compared the surgical outcomes of more than 1,500 patients with average BMIs of 52 who underwent duodenal switch with those of nearly 77,500 patients with average BMIs of 48 who underwent gastric bypass.

According to their findings, duodenal switch procedures last longer, while resulting in greater blood loss and longer hospital stays, but deliver significantly greater weight loss (79% vs. 67%) and much lower weight-loss failure rates (50% vs. 6%) at 2 years post-op. The researchers also report significant improvement or resolution of co-morbidities such as diabetes, hypertension, high cholesterol and obstructive sleep apnea, according to the results.

The researchers concede that the duodenal switch isn't performed as often as gastric bypass, perhaps because it's a more technically challenging procedure and slightly riskier in the short-term, but they tout its long-term benefits.

In an accompanying commentary, Alec Beekley, MD, of Thomas Jefferson University Hospitals in Philadelphia, notes that surgeons are seeing a significant number of patients gain weight after gastric bypass. He adds, "Duodenal switch has superior weight loss and may be more appropriate as the primary bariatric operation in carefully selected patients."

Daniel Cook

Warming Up to Normothermia

The benefits of keeping patients warm throughout the perioperative process have been proven thoroughly and espoused by more than one clinical authority as a standard of care. But maintaining normothermia from the pre-op bay to discharge means more than just draping the patient with a freshly warmed cotton blanket.

Find out how IV fluids, the thermostat, booties, hot air and your nurses' assessments play a role in preventing hypothermia, forestalling surgical site infections and keeping patients comfortable with this rundown of strategies for effective patient warming.

David Bernard

InstaPoll: Aromatherapy for Treating PONV

Aromatherapy has long been used as a complementary modality for the prevention and management of post-operative nausea and vomiting. It's shown promise in some studies as a rescue therapy for PONV, but many feel that inhalation therapy is not as effective as traditional anti-emetics. Tell us how you feel about aromatherapy in Outpatient Surgery Magazine's InstaPoll.

Obama or Romney? Last week's poll of 1,310 surgical facility leaders shows Mitt Romney holds a commanding lead over President Barack Obama. We asked "If the presidential election were held today, how would you vote?" The results:

  • Barack Obama: 29%
  • Mitt Romney: 64%
  • Undecided: 5%
  • Abstain: 2%

Dan O'Connor

News & Notes
  • Bariatric surgery reduces medication dependence Patients who undergo weight-loss surgery require fewer medications for treating diabetes and cardiovascular disease at 6 years post-op and beyond, lowering average annual drug costs by nearly $200 per individual, reports a study in the Journal of the American Medical Association. Bariatric surgery patients also saw reduced incidence of cancer, improved 10- to 15-year survival rates and dropped an average of 44 more pounds of sustained weight loss than individuals who followed non-surgical weight-loss regimens.
  • How obesity dislocates hip implants Why are morbidly obese patients more likely to see hip implants fail? Their reduced ranges of motion don't usually risk dislocation, physicians note. According to researchers at the University of Iowa who've studied computer simulations of implant dislocations, however, a larger body size may mean joint instability. "We have shown that morbidly obese patients' thighs are so large that they are actually pushing each other outward and forcing the implant out of its socket," says one. Their study, published in the journal Clinical Orthopaedics and Related Research, suggests surgeons carefully consider implant techniques and design among obese patients.
  • Joint repair doesn't equal weight loss Since the aim of joint replacement surgery is to reduce pain and restore mobility, clinicians have long speculated that it could enable greater physical activity and burned calories. But a recent analysis by a researcher at San Diego State University finds no proof that this is a certainty. Reviewing 12 previous studies, she found that weight loss is not a consistent occurrence among joint surgery patients.