Comparison of the Effect of Preemptive and Post-operative Erector Spina Plane Block on Intraoperative Opioid Consumption and Postoperative Analgesia in Patients Who Will Undergo Elective Thoracotomy Surgery, Guided by the Nociception Level Index (NoL)

The patients who will participate in the study will be determined and informed according to the inclusion and exclusion criteria, and the patients who signed the informed consent form will be included in the study.52 patients who will undergo elective thoracotomy surgery will be divided into double-blinded 2 sided as preemptive and postoperative erector spina plane block. Intraoperative pain status of the patients will be determined by the "Nociception Level Index" device and analgesia will be provided with fentanyl. The primary aim of the study is to compare the intraoperative opioid consumption of two groups with plan block at different times. In the postoperative period, patient-controlled analgesia device will be given to both groups for rescue analgesia. The opioid consumption of the patients will be controlled in this way in the postoperative period and their pain status will be determined. The secondary aim of the study is to examine the effect of plan block application time on the postoperative period.