Pressure Pain Hyperalgesia Expressed by Topographical Pressure Pain Sensitivity after Cardiac Surgery

We aim to evaluate changes in pressure pain sensitivity before and after cardiac surgery using topographical sensitivity maps utilizing a pressure algometer. Pressure pain thresholds over 17 thoracic points and 4 distant pain-free points were assessed in 70 patients (women: 29, age: 67.5 years), before and at 1, 3, and 7 postoperative days. Thoracic topographical pressure pain sensitivity maps were calculated at all follow-ups. Postoperative pain was recorded at each follow-up on a numerical pain rate scale. Postoperative pain intensity decreased from 6.4 (SD 1.0) on the first postoperative day to 5.5 (SD 1.9) on the third and to 4.5 (SD 1.7) on the seventh day ( < 0.001). The mixed-model ANOVA revealed that the lowest pressure pain thresholds were observed one day after surgery, increased slightly during follow-up, and were lower at the xiphoid process. Significant negative correlations between postoperative pain intensity and pressure pain thresholds were observed at each time point in thoracic measures (all, < 0.01), but not with pressure pain thresholds from distant pain-free areas. Postoperative pain after cardiac surgery can be objectively quantified using algometry. Pressure pain hyperalgesia was associated with the intensity of postoperative pain.