STANFORD, Calif — December 2, 2009 — The right kind of stress response in the operating room could lead to quicker recovery for patients after knee surgery, according to a new study led by Stanford University School of Medicine researchers. The results suggest that simple, inexpensive blood tests performed while patients are on the operating table could predict how well patients will have recovered months after they leave the hospital. Eventually, doctors might also be able to develop medical interventions to improve that recovery.
The study, conducted with colleagues at Yale University and published in the Journal of Bone and Joint Surgery, found that patients whose immune systems responded to the stress of surgery by mobilising large numbers of pathogen-fighting cells and redistributing them to skin and other tissues recovered more quickly and completely than those patients whose immune system showed little or no reaction. The researchers also found that men were more likely than women to mount the beneficial stress response and recover more fully.
“One of the beauties of the tests is that it’s so easy,” said Esther Sternberg, MD, National Institute of Mental Health, Bethesda, Maryland, who was not involved in the research. “The information is completely available to any physician pre- and post-surgery.”
Old models of stress and the immune system predicted that stressful situations would suppress immune activity. But Firdaus Dhabhar, PhD, Stanford University, Stanford, California, senior author of the paper, said those models didn’t differentiate between unhealthy chronic stress, which can negatively affect the immune system, and healthier short-term stress. Short-term stress, Dr. Dhabhar said, launches the fight-or flight response, which he described as “one of nature’s fundamental protective survival mechanisms.”
“In nature, wounds and infections often occur during stressful situations, or cause stress soon after they occur. Therefore, we reasoned that the short-term stress response would prepare organisms for immune challenges, just as it prepares them for fight-or-flight,” said Dr. Dhabhar.