Vol.:(0123456789) 1 3 J Clin Monit Comput DOI 10.1007/s10877-017-0036-9 ORIGINAL RESEARCH Analgesia nociception index (ani) monitoring in patients with thoracic paravertebral block: a randomized controlled study Nurseda Dundar 1  · Alparslan Kus 1  · Yavuz Gurkan 1  · Kamil Toker 2  · Mine Solak 1   Received: 11 November 2016 / Accepted: 13 June 2017 © Springer Science+Business Media B.V. 2017 consumption (Group ANI: 629.6 ± 422.4 mcg, Group con- trol: 965.2 ± 543.6 mcg) (p = 0.027). In patients under gen- eral anesthesia ANI monitorisation can help optimisation of opioid consumption and provide data about nociception/ antinociception intraoperatively but further experimental and clinical trials in a large scale are needed. Keywords Analgesia nociception index · Thoracic paravertabral block · Pain monitoring 1 Introduction Regional anesthesia administered along with general anes- thesia decreases the stress response associated with surgery and diminishes the need for opioid use. Hemodynamic parameters are generally used to determine the intraopera- tive need for opioids in patients; however, hemodynamic parameters are not standardized and they do not provide a clear assessment [1]. In view of the developments in technology, there is increasing clinical use of objective methods such as pupi- lometry, skin vasomotor refex analysis, pulse plethysmo- graphic signals, and analgesia nociception index (ANI) to determine the need of intraoperative analgesia in patients undergoing general anesthesia [2, 3]. ANI is a parameter that refects the balance between nociception and analgesia under general anesthesia based on analysis of cardiac rate variability. It provides qualita- tive and quantitative measurements of heart rate variability based on the analysis of the efect of breathing on RR (the distance between R waves of two QRS complexes) series by using data derived from two electrodes placed on the sternum and left mid-axillary line [4, 5]. Abstract The goal of the study was to evaluate the efec- tiveness of analgesia nociception index (ANI) monitoring during intraoperative period for patients with thoracic para- vertebral block (TPVB) undergoing breast surgery under general anesthesia. This prospective randomized trial was performed after receiving ethics committee approval in 44 patients who were scheduled to undergo breast surgery under general anesthesia. TPVB was performed in the pre- operative period using 20 mL of bupivacaine 0.25% at T4 level. Anesthesia maintenance was provided with sevofu- rane in O 2 : air mixture and remifentanil infusion. Intraop- erative concentration of sevofurane was adjusted according to BIS monitoring keeping the values between 40–60. In a randomized manner patients were divided into two groups. In Group control (n:22) intraoperative remifentanil infusion rate was regulated according to hemodynamic parameters, in Group ANI (n:22) remifentanil infusion rate was titrated to keep ANI monitoring values between 50–70. Total remifentanil consumption was recorded as micrograms. Demographic data, anesthesia and surgery time, intraop- erative hemodynamic parameters, post-anesthesia recovery time and requirement of additional analgesic in the recov- ery drug were recorded. There were no signifcant difer- ence in demographic data, intraoperative hemodynamic parameters, post-anesthesia recovery time and requirement of additional analgesic drug. There was a statistically sig- nifcant diference between groups in total remifentanil * Nurseda Dundar d.nurseda@hotmail.com 1 Department of Anesthesiology and Reanimation, School of Medicine, Kocaeli University, Kocaeli, Turkey 2 Department of Anesthesiology and Reanimation, School of Medicine, Bahçeşehir University, Istanbul, Turkey