The effect of neutrophil / lymphocyte ratio on postoperative pain and chronicization of pain in thoracotomy

Aim: Pain after thoracotomy adversely affects postoperative patient comfort, complications, mortality and morbidity. Therefore, pain management after thoracotomy is very important. The aim of our study is to investigate the relationship between the Neutrophil/Lymphocyte Ratio (NLR), an inflammation marker, and postoperative acute and chronic pain in thoracic surgery, and to evaluate the relationship between epidural analgesia applied at different times and preoperative NLR. Materials and Methods: The study was conducted as a randomized prospective study in a total of 60 patients, aged 18-75 years, ASA I-II-III risk class, who underwent thoracotomy surgery under elective conditions, with informed consent. The patients included in the study were randomly divided into 2 groups: In the group to be administered preemptive analgesia (Group P), a bolus of 0.1 ml/kg of 0.25% bupivacaine was administered through the epidural catheter 20 minutes before the surgical incision, and an infusion of 0.1% bupivacaine at a rate of 0.1 ml/kg/h for 48 hours was started. In the control group (Group K), a bolus of 0.1 ml/kg of 0.25% bupivacaine was administered 20 minutes before the patient was awakened from the epidural catheter, and an infusion of 0.1% bupivacaine at a rate of 0.1 ml/kg/h for 48 hours was started. Preoperative NLR values, intraoperative and postoperative systolic, diastolic and mean arterial pressures, heart rate, peripheral oxygen saturations of all patients at 5th, 30th, 60th and 120th minutes and after extubation at 2nd, 4th, 8th, 12th, 24th hours have been recorded. NRS, respiratory rate and need for additional analgesia were recorded at the 2nd, 4th, 8th, 12th and 24th hours postoperatively. In the 1st and 3rd months postoperatively, the patients were contacted by phone and their NRS scores were recorded. Results: When the intraoperative and postoperative hemodynamic parameters of the groups were evaluated, no statistically significant difference was observed between the two groups (p>0.05). When the postoperative NRS values and additional analgesic consumption in the first 24 hours were compared between the groups; NRS values at postoperative 2nd, 4th and 8th hours and additional analgesic consumption in the first 24 hours were found to be significantly lower in Group P compared to Group K. When postoperative NRS values and additional analgesic consumption were compared between patients with preoperative NLR<2 and preoperative NLR≥2 in Group P; no statistically significant difference was found between the two groups (p>0.05). However, when postoperative NRS values and additional analgesic consumption were compared between patients with preoperative NLR<2 and preoperative NLR≥2 in Group K; in the patient group with preoperative NLR<2, the NRS levels at the postoperative 2nd, 4th and 8th hours and the amount of additional analgesic consumed in the postoperative first 24 hours were statistically significantly lower than in the patient group with preoperative NLR≥2. When evaluated in terms of chronic pain, it was seen that whether preemptive analgesia was applied or not and preoperative NLR level had no effect on pain levels in the chronic period. Conclusion: When preemptive epidural analgesia method was applied to patients with preoperative NLR level of 2 and above, it was observed that pain scores and analgesic consumption were lower in the postoperative acute period compared to the group that received epidural analgesia 20 minutes before awakening. It was observed that the postoperative pain level and analgesic consumption of patients with preoperative NLR level below 2 did not change with whether or not preemptive analgesia was applied. In addition, no relationship was found between the preoperative NLR level and the chronicity of pain. Key Words: Preemptive Epidural Analgesia, Neutrophil / Lymphocyte Ratio, Postoperative Pain, Chronic Pain.