Is there a relationship between body mass index and postoperative pain scores in thoracotomy patients with thoracic epidural analgesia?

Postoperative efficacy of thoracic epidural analgesia (TEA) following thoracic surgery may vary in patients with different body mass index (BMI) values, regardless of the success of the method. This study aimed to investigate the effects of BMI on postoperative pain scores in patients who underwent thoracotomy with TEA. After obtaining the ethical committee approval (Date: May 11, 2021, Number: 2012-KEAK-15/2305) the data of 1326 patients, who underwent elective thoracic surgery in high volume tertiary thoracic surgery center between January 2017 and January 2021, were analyzed retrospectively. Patients between the age of 18 and 80years, who underwent thoracotomy and thoracic epidural catheterization (TEC), and who were assigned American Society of Anesthesiologists I to III physical status were included to the study. Of the 406 patients, who underwent a successful TEC, 378 received postoperative analgesia for 72hours. Visual analog scale (VAS) scores of these patients were evaluated statistically. Based on BMI, patients were categorized into the following 5 groups: Group I: BMI < 20kg/m2, Group II: BMI=20 to 24.9kg/m2, Group III: BMI=25 to 29.9kg/m2, Group IV: BMI=30 to 34.9kg/m2, and Group V: BMI ≥ 35kg/m2. There were no statistically significant differences in TEC success across different BMI groups (P>.05). Catheter problems and VAS scores significantly increased with higher BMI values in the postoperative 72-hours period (P<.05). Rates of rescue analgesic use were higher in BMI groups of 30 toto 34.9kg/m2 and ≥35kg/m2 compared to the other BMI groups. This study revealed that higher BMI in patients may increase VAS scores, who administered TEA for pain management following thoracotomy. This correlation was supported by the increased need for additional analgesics in patients with high BMI. Therefore, patients with high BMI values would require close monitoring and follow-up. Abbreviations: BMI = body mass index, IQR = interquartile range, iv = intravenous, T = thoracic, TEA = thoracic epidural analgesia, TEC = thoracic epidural catheterization, VAS = visual analog scale.