Perception of bodily sensation as a predictor of treatment response to acupuncture for postoperative nausea and vomiting prophylaxis

OBJECTIVES: Conditions associated with the response to acupuncture treatment remain widely elusive. This study aimed to identify predictors of treatment response in patients undergoing acupuncture treatment for prevention of postoperative nausea and vomiting (PONV). An intervention-specific questionnaire was developed to assess perception of bodily sensations (PBS) in patients undergoing acupuncture treatment. DESIGN: Exploratory study in addition to an observer-blinded randomized controlled trial. SETTINGS/LOCATION: The departments of anesthesiology and of gynecology, University of Heidelberg, Germany. SUBJECTS: Two hundred and twenty (220) female patients scheduled for breast or gynecologic surgery. INTERVENTIONS: True acupuncture on point P6 (Neiguan) or placebo/sham acupuncture on a virtual point 1 cm proximal and lateral to P6. OUTCOME MEASURES: Of 220 female patients scheduled for breast or gynecologic surgery who were included in the trial, 202 completed the newly developed PBS questionnaire before the intervention. The main outcome was incidence of PONV in relationship with PBS and the kind of acupuncture applied. Logistic regression analyses were performed to identify predictors of treatment response for those receiving surgery (n = 195). RESULTS: High PBS predicted low treatment response in patients receiving breast surgery (odds ratio [OR] = 1.6; p = 0.039 for each 10-point increase). The PBS questionnaire showed good item difficulty, internal consistency, and divergent validity. Treatment response in patients receiving gynecologic surgery was predicted by the kind of acupuncture applied (OR = 0.4; p = 0.027), whereas PBS played no role in this group. CONCLUSIONS: The incidence of PONV after breast surgery seems to be influenced by some psychological mechanisms. In this group of patients, acupuncture might be more effective in patients who have low PBS.