Combination of ultrasound-guided pectoral nerve block I (PECS I) and serratus anterior plane block (SAP) for attenuation of surgical stress response during modified radical mastectomy: a prospective interventional randomized controlled trial

Background and Aims General anesthesia with multimodal analgesia is the standard anesthetic management during modified radical mastectomy. In this study, a combined ultrasound-guided pectoral nerve block (PECS I) and serratus anterior plane block (SAP) were used for surgical stress response attenuation and postoperative analgesia. Methods Thirty-six consenting patients were randomized into two groups. After induction of general anesthesia, Group B patients received ultrasound-guided PECS I and SAP block whereas Group C patients received intravenous analgesics only. Intraoperative fentanyl dosage to keep the systolic blood pressure (SBP) and heart rate (HR) within 20% of baseline was the primary outcome variable. Secondary outcome variables were intraoperative vitals, postoperative pain score, analgesic requirement, and nausea and vomiting. Wilcoxon rank-sum test (non-parametric data), Student's t-test (parametric data), and Chi-square test (categorical data) were used for comparison. P value <0.05 was considered statistically significant. Results Surgical stress response attenuation was achieved with a lower dosage of fentanyl in Group B compared to Group C [intraoperative fentanyl (mean±SD), 116.11±25.70 µg vs. 134.44±20.07 µg, P = 0.023]. Compared to Group C, intraoperative reduction in SBP and HR was higher in Group B [SBP reduction (mean±SD), 24.03±12.5 mm of Hg vs. 15.2±13.05 mm of Hg, P = 0.045 and HR reduction (mean±SD), 18.61±6.6 beats/min vs. 10.73±10.03 beats/min, P = 0.009 respectively]. The apparently higher pain scores in the control group were statistically insignificant. Conclusion A combined PECS I and SAP block attenuates intraoperative autonomic stress response due to the surgical stimulus with significantly less opioid requirement. Trial Registration: CTRI/2023/03/050487. This trial is registered with the Clinical Trial Registry of India ON 09/03/2023. https://ctri.nic.in/Clinicaltrials/login.php