Translation and Validation of the Thai Version of a Modified Brief Pain Inventory: A Concise Instrument for Pain Assessment in Postoperative Cardiac Surgery

BackgroundAcute pain after cardiac surgery can be assessed using validated instruments such as the modified interference subscale of the Brief Pain Inventory (mod-BPI). Despite the available knowledge, the Thai version of a mod-BPI has not yet been presented. ObjectivesTo translate a mod-BPI into the Thai language (BPI-T) and to validate it in acute pain after cardiac surgery. MethodsThis multisetting, cross-sectional study was done from 4 cardiac centers. With a convenience sampling technique, 132 cardiac surgery patients were enrolled during the first 72 postoperative hours. A BPI-T composed of 4 items on the intensity subscale and 6 items on the interference subscale was translated following Brislin's model. Convergent validity against the numeric rating scale (NRS), confirmatory factor analysis (CFA), and internal consistency reliability were examined. ResultsOf the total sample, 70% experienced moderate to severe pain (cutoff points of worst pain 4/10), and 65% had moderate to severe interference with deep breathing and coughing, 53% with general activity, and 49% with walking. The CFA confirmed the 2-factor structure of intensity and interference subscales consistent with the original version (root-mean-square error of approximation = 0.08, comparative fit index = 0.95, (2) = 39.00, df = 27, (2)/df = 1.44, P = 0.06). The physical and mental subdimensions under the interference subscale were determined (standardized factor loading = 0.70 and 0.42, respectively). The BPI-T also has good internal consistency (Cronbach's alpha coefficients 0.76 and 0.85). Pearson's correlation coefficients at 0.35 to 0.70 supported the convergent validity to the NRS. ConclusionsThe BPI-T is a concise instrument for pain assessment in postoperative cardiac surgery.