Valoración cualitativa y cuantitativa del dolor posoperatorio agudo en cirugía cardiaca

Background: Origin of postoperative pain after cardiac surgery is multifactorial. It varies according to patient characteristics, preoperative situation and technical issues related to surgery, finally leading to a pain of difficult management. Scales and questionnaires validated to assess postoperative pain are inherently subjective and are biased by the perception of the patient. However, few studies have been performed to objectively evaluate the postoperative pain after cardiac surgery. Algometry is a simple, objective, non-invasive technique, developed to quantify musculoskeletal pain by determining pressure pain thresholds (PPT). Its application would allow identifying the PPTs before and after the intervention. Aim: The primary aim of the current study was to determine changes in pressure pain sensitivity measured by algometry before and after cardiac surgery. The secondary aims were to identify the demographic and clinical factors associated with the presence, location and changes of postoperative pain during the postoperative period, as well as to evaluate the correlation between subjective and objective measurements. Finally, to determine variations in postoperative pain related to modifiable factors of clinical practice: surgical approach, sternal suture technique and the use of thoracic sternal support, as well as the history of preoperative COVID-19 infection. Materials and Methods: A prospective, observational study of a single-center was designed. 70 patients consecutively undergoing cardiac surgery were included during 6 months. PPTs were determined by using a pressure algometer with a rubber tip. PPTs were measured preoperatively and on one, three, and seven postoperative days (POD) at 22 sites. Topographic pain sensitivity maps were created at each follow-up to visualize changes in thorax pressure sensitivity over time. Results: Postoperative pain intensity, as measured by algometry, decreased significantly from 6.4 (SD 1.0) on POD 1 to 5.5 (SD 1.9) on POD 3 and 4.5 (SD 1.7) on POD 7 (p<0.001). ANOVA analysis showed the lowest PPTs on POD 1 (p<0.001), with a slight increase on POD 3 (p<0.001) and POD 7 (p=0.01), although baseline values were not recovered. The xiphoid process consistently exhibited the lowest postoperative PPT throughout the follow-up period, with no significant differences between patients undergoing full sternotomy versus ministernotomy. Analysis of demographic variables revealed that women and patients over 65 years of age exhibited lower PPTs at all time points, indicating greater sensitivity to pressure pain. No significant differences in PPT were observed based on the surgical approach or sternal closure technique. Conclusions: Postoperative pain in cardiac surgery can be objectively quantified using algometry, based on the demographic and clinical characteristics of the patient. Changes in PPTs have enabled the development of topographic pain sensitivity maps for the thorax, providing a novel tool for understanding postoperative pain patterns in cardiac surgery.