Fig. 1

a Average dose of intraoperative remifentanil use in the TIVA and TIVA + PECSB groups. Data are shown as the means ± SDs. ***p < 0.001 by unpaired Student’s t tests. b Histogram and cumulative probabilities of intraoperative remifentanil dose in patients who underwent BCS with TIVA or TIVA + PECSB. Red and blue bars denote the frequency of increases in intraoperative remifentanil doses (2 μg/kg/h) in the TIVA and TIVA + PECSB groups, respectively. Red triangles and purple crosses denote the cumulative distribution of intraoperative remifentanil doses in the TIVA and TIVA + PECSB groups, respectively