The investigator's goal in this study is to apply PECS II block, before starting surgery, by either conventional USG or artificial intelligence integrated USG to patients who will undergo mastectomy under general anesthesia to determine the effect of the block on hemodynamics and opioid consumption in the intraoperative period. Besides, the investigatorwanted to investigate the contribution of artificial intelligence integrated USG use in the success of a 4-year anesthesiology resident for imaging the injection site.

After receiving the approval of the Clinical Research Ethics Committee of Başkent University (KA21/353), 70 patients with ASA I-II, between the ages of 18-75, who were scheduled for mastectomy surgery were included in the study. A 4. year anesthesiology resident under the supervision of two senior anesthesiologists, performed a PECS II block with AI-integrated USG or conventional USG (Group AI-USG and Group USG) after randomization. Although the resident had no experience with pectoral blocks, she had experience with the use of USG and regional anesthesia related to other trunk-area and peripheral blocks. The block was performed after induction of general anesthesia. Patient data in terms of hemodynamic changes in the intraoperative period, opioid (remifentanil) consumption, and postoperatively hemodynamics, pain scores (VAS), postoperative opioid [tramadol administered with a patient-controlled analgesia pump (PCA)] and, if necessary, rescue analgesic agent (non-steroidal antiinflammatory agent) consumption were monitored in the post anesthesia care unit (PACU), and at postoperative 6., 12. and 24.hours.

Inclusion Criteria:

• 18-70 years
• ASA I and II
• Female
• Underwent mastectomy surgery
• Without local anesthetic allergy

Exclusion Criteria:

• Patients with ASA III and above
• Obesity (body mass index >30)
• Psychotropic drug use
• Bleeding diathesis
• Local anesthetic allergy
• Chest wall deformity
• Infection at the injection site
• Chronic analgesic usage