Location and Patterns of Persistent Pain Following Cardiac Surgery.

OBJECTIVES: To investigate the specific clinical features of pain following cardiac surgery and evaluate the information derived from different pain measurement tools used to quantify and describe pain in this population. METHODS: A prospective observational study was undertaken at two tertiary care hospitals in Australia. Seventy-two (72) adults (mean age, 63±11 years) were included following cardiac surgery via a median sternotomy. Participants completed the Patient Identified Cardiac Pain using numeric and visual prompts (PICP), the McGill Pain Questionnaire-Short Form version 2 (MPQ-2) and the Medical Outcome Study 36-item version 2 (SF-36v2) Bodily Pain domain (BP), which were administered prior to hospital discharge, 4 weeks and 3 months postoperatively. RESULTS: Participants experienced a high incidence of mild (n=45, 63%) to moderate (n=22, 31%) pain prior to discharge, which reduced at 4 weeks postoperatively: mild (n=28, 41%) and moderate (n=5, 7%) pain; at 3 months participants reported mild (n=14, 20%) and moderate (n=2, 3%) pain. The most frequent location of pain was the anterior chest wall, consistent with the location of the surgical incision and graft harvest. Most participants equated "pressure/weight" to "aching" or a "heaviness" in the chest region (based on descriptor of pain in the PICP) and the pain topography was persistent at 4 weeks and 3 months postoperatively. Each pain measurement tool provided different information on pain location, severity and description, with significant change (p<0.005) over time. CONCLUSION: Mild-to-moderate pain was frequent after sternotomy, improved over time and was mostly located over the incision and mammary (internal thoracic) artery harvest site. Persistent pain at 3 months remained a significant problem in the community within this surgical population.

Psychometric evaluation of the shortened version of the Functional Difficulties Questionnaire to assess thoracic physical function.

OBJECTIVE: The aim of this study was to investigate the psychometric properties of the shortened version of the Functional Difficulties Questionnaire (FDQ). DESIGN: This is a multisite observational study. SETTING: The study was conducted in four tertiary care hospitals in Australia. SUBJECTS: A total of 225 participants, following cardiac surgery, were involved in the study. INTERVENTION: Participants completed the original 13-item FDQ and other measures of physical function, pain and health-related quality of life. METHOD: Item reduction was utilized to develop the shortened version. Reliability was evaluated using intraclass correlation coefficients (ICCs), the smallest detectable change and Bland-Altman plots. The validity and responsiveness were evaluated using correlation. Anchor and distribution-based calculation was used to calculate the minimal clinical important difference (MCID). RESULTS: Item reduction resulted in the creation of a 10-item shortened version of the questionnaire (FDQ-s). Within the cohort of cardiac surgery patient, the mean (SD) for the FDQ-s was 38.7 (19.61) at baseline; 15.5 (14.01) at four weeks and 7.9 (12.01) at three months. Validity: excellent internal consistency (Cronbach's α > 0.90) and fair-to-excellent construct validity (>0.4). Reliability: internal consistency was excellent (Cronbach's α > 0.8). The FDQ-s had excellent test-retest reliability (ICC = 0.89-0.92). Strong responsiveness overtime was demonstrated with large effect sizes (Cohen's d > 1.0). The MCID of the FDQ-s was calculated between 4 and 10 out of 100 (in cm). CONCLUSION: The FDQ-s demonstrated robust psychometric properties as a measurement tool of physical function of the thoracic region following cardiac surgery.