References
post-sternotomy, T4, ESPB
Flowchart for NOL index-based fentanyl administration. The optimum nociception–antinociception balance is a NOL index between 10 and 25. Outside this range, fentanyl should be either decreased to avoid overdosing (i.e., NOL index < 10) or increased to prevent underdosing and nociception (i.e., NOL index > 25). NOL, nociception level.Intergroup comparison (Control vs. ESPB) for the average NOL index value across the five sampling time points. The data are presented as least square adjusted means. For Control vs. ESPB, Intergroup comparison (Control vs. ESPB) by time for the NOL index value. The data are presented as least square adjusted means. Time points: T1 (pre-incision), Pairwise intragroup comparison (Control, ESPB) between consecutive NOL index time points. Time point comparisons: pre-incision (T1) vs. post-incision (T2); T2 vs. pre-sternotomy (T3); T3 vs. post-sternotomy (T4); and T4 vs. pre-CPB (T5). The data are presented as least square adjusted means. Control group: Alluvial diagram showing the flow of patients across five NOL index sampling time points. (Baseline and perioperative patient characteristics.Values are mean ± SD, median (IQR, 25th–75th percentiles), or number [percentages]. There were no intergroup differences for any parameter. Intergroup and intragroup comparison of the NOL index time course.Values are least square adjusted (LSA) means ± SE and 95% confidence interval (CI) for LSA means. The intergroup comparison shows that the NOL index was significantly lower in the ESPB-to-Control group as an average over the five sampling time points (Tav) and at post-incision (T2), pre-sternotomy (T3), and post-sternotomy (T4) but not at pre-incision (T1) and pre-CPB (T5). The intragroup pairwise comparison between consecutive time points reflects a fluctuating response to nociception in the control group compared to the ESPB group. Analysis was performed using a mixed model for repeated measurements (MMRM) with random intercepts for patients. MMRM indicated main effects of group (Intergroup comparison of number of patients with nociceptive response.Values are number [percentages]. A nociceptive response to noxious stimuli is considered a NOL index > 25. Analysis was performed using the χ2 test or Fisher’s exact test, as appropriate. Abbreviations: ESPB, erector spinae plane block; NOL, nociception level; T1, pre-incision; T2, post-incision; T3, pre-sternotomy; T4, post-sternotomy; T5, pre-CPB.