Research Shows that Simple Tests May Help Predict Patients’ Pain after Surgery

October 24, 2005

WINSTON-SALEM, N.C. – New research at Wake Forest University Baptist Medical Center shows that having patients complete a series of simple tests before surgery may help predict the intensity of their post-surgical pain and how much pain medication they will need.

“Despite advances in pain management, recent surveys revealed that a high percentage of hospitalized patients nationwide continue to experience moderate to severe pain after surgery,” said Peter H. Pan, M.D., an obstetrical anesthesiologist and the lead researcher. “Our ultimate goal is to learn how to predict which patients are at risk for excessive pain so we can tailor treatment to them.”

Pan presented the study results today at the American Society of Anesthesiology Annual Scientific Meeting in Atlanta.

The research was designed to address a dilemma in pain management – determining the right amount of pain medication for each patient. If patients are undertreated and have severe pain, it can lead to ongoing, chronic pain. On the other hand, over treatment with pain medicine is associated with bothersome side effects.

The Joint Commission on Accreditation of Healthcare Organizations has set a goal for hospitals to develop standards for assessing and treating pain so that patients don’t experience pain above a “3” on a 10-point scale. Determining the best dose for each patient can be difficult because of individual differences in pain tolerance, according to Pan.

“Requirements for pain medication and the severity of pain experienced by patients can be influenced by sensitivity to pain, levels of anxiety, age, genetics and expectations about pain,” he said. “However, few studies have explored whether physical and psychological responses obtained before surgery can be used together to predict the severity of pain and pain medication required after surgery.”

For the study, the researchers looked at whether a variety of simple tests could predict post-surgical pain in 34 women scheduled to have elective cesarean sections. About two weeks before surgery, the women answered questionnaires to measure anxiety, their expectations about pain and the levels of pain they were having during pregnancy. In addition, a small heat element was applied to their arms and backs and the women were asked to rate the intensity and unpleasantness. The heat, which ranged from 95 to 122 degrees, was not applied long enough to cause skin damage and could be stopped by the patient at anytime.

After surgery, the women reported on their pain severity levels and researchers measured their requirements for pain medication. The researchers found that six groups of predictive factors accounted for 90 percent of the total variances in patients’ post-surgical pain severity and medication requirements.

The best predictor of the total amount of pain medication required was a validated questionnaire that measured anxiety. The best predictors of overall post-surgical pain were blood pressure readings shortly before surgery and patients’ responses to the heat element that was performed before surgery. The model was also useful in identifying patients in the top 20 percent of pain severity and amount of pain medication required after surgery.

“More research is needed to develop a more complete model,” said Pan, “but the study shows the potential to identify patients at risk for high pain levels after surgery so we can tailor treatments to improve their quality of care.”

Pan’s co-investigators were Robert Coghill, Ph.D., Timothy T. Houle, Ph.D., Lynne Harris, B.S.N., and James C. Eisenach, M.D., all from Wake Forest University Baptist Medical Center, and Melvin H. Seid, M.D., W. Michael Lindel, M.D., R. Lamar Parker, M.D., and Scott Washburn, M.D., from Lyndhurst Gynecological Associates in Winston-Salem.


Media Contacts: Karen Richardson,; or Ann Hopkins,; at 336-716-4587.

About Wake Forest University Baptist Medical Center: Wake Forest Baptist is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university’s School of Medicine. The system comprises 1,282 acute care, psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of “America’s Best Hospitals” by U.S. News & World Report.

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