The relationship of surgical pleth index values ​​observed at the end of the surgical procedure with postoperative pain score and analgesia consumption

OBJECTIVE: In this prospective observational study, it was aimed to investigate the role of SPI values observed at the end of elective cranial surgery in determining acute pain in the postoperative period. MATERIAL AND METHODS: After ethics committee approval and patient consent was obtained, patients who underwent elective cranial surgery between January 2019-June 2021, aged between 18-65 years, ASA scores between I-III were included in the study. The SPI values observed at the end of the surgery were recorded and postoperative pain was evaluated with NRS. Demographic data of the patients, preoperative status and data related to the operation, and postoperative follow-up data were noted. RESULTS: As a result of the statistical analysis performed on 52 patients who participated in the study, it was observed that there was a correlation between the highest SPI value recorded for five minutes before SE>60 and the highest NRS score observed during the postoperative 30 minutes (r=0,480, p<0,001). After the data obtained by recording the NRS scores in the postoperative period, patients were divided into two groups: High NRS Group (NRS≥5), Low NRS Group (NRS<5). There was a significant difference between the SPI values of the patients in the High and Low NRS Groups (p<0,05). The predictability of the highest SPI value measured in the postoperative period that the NRS score of the patient would be 5 and above at least once, that is, whether the NRS score would be high or not, was evaluated with the ROC curve (AUC=0.796 [%95CI:0.675-0.918]). When the cut-off value was accepted as 75,5, the specificity of the SPI value in predicting postoperative acute pain was 72%, and the sensitivity was 71%. CONCLUSION: In this study, it has been shown that SPI values observed after craniotomy operations can predict postoperative moderate-to-high grade acute pain. Non-invasive SPI monitoring may reduce the complications caused by increased opioid use, thus shortening the hospital stay and reducing the cost.