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Updated: Sep 10, 2025

An Experimental Paradigm for the Prediction of Post-Operative Pain PPOP
Published on: January 27, 2010
Relationship Between Local Anesthetic Infiltration Pain Before Spinal Anesthesia and the Analgesia Nociception Index
Hiroaki Kondo1,2, Shunsuke Hyuga1,2, Miho Shishii1,2
1Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, JPN.
Background Heart rate variability-derived indices, such as the high-frequency vitality index (HFVI)/analgesia nociception index (ANI), have been proposed as objective pain assessment tools. However, their ability to predict pain perception during local anesthetic injection (LAI) remains unclear. Methods This single-center observational study included 44 pregnant women scheduled for cesarean delivery under spinal anesthesia. The HFVI/ANI was measured for five minutes before LAI using a Root® monitor (Masimo Corp., Irvine, CA). The primary outcome measure was the mean HFVI/ANI before LAI during spinal anesthesia. The secondary outcomes included the area under the receiver operating characteristic curve to determine the cut-off and predictive accuracy. Results There was no significant difference in the pre-LAI HFVI/ANI between the patients with visual numeric rating scale (VNRS) of ≤3 and those with VNRS of >3 (HFVI: 64.25 ± 11.8 vs. 62.64 ± 12.3, P = 0.66). ROC analysis revealed poor predictive ability (AUC = 0.54, 95% CI: 0.36-0.72). No significant correlation was found between HFVI/ANI and VNRS. Conclusion Pre-LAI HFVI/ANI values were not associated with pain perception during LAI during cesarean delivery. Further studies are needed to explore optimal indicators for HFVI/ANI-based pain assessment.
Background Heart rate variability-derived indices, such as the high-frequency vitality index (HFVI)/analgesia nociception index (ANI), have been proposed as objective pain assessment tools. However, their ability to predict pain perception during local anesthetic injection (LAI) remains unclear. Methods This single-center observational study included 44 pregnant women scheduled for cesarean delivery under spinal anesthesia. The HFVI/ANI was measured for five minutes before LAI using a Root® monitor (Masimo Corp., Irvine, CA). The primary outcome measure was the mean HFVI/ANI before LAI during spinal anesthesia. The secondary outcomes included the area under the receiver operating characteristic curve to determine the cut-off and predictive accuracy. Results There was no significant difference in the pre-LAI HFVI/ANI between the patients with visual numeric rating scale (VNRS) of ≤3 and those with VNRS of >3 (HFVI: 64.25 ± 11.8 vs. 62.64 ± 12.3, P = 0.66). ROC analysis revealed poor predictive ability (AUC = 0.54, 95% CI: 0.36-0.72). No significant correlation was found between HFVI/ANI and VNRS. Conclusion Pre-LAI HFVI/ANI values were not associated with pain perception during LAI during cesarean delivery. Further studies are needed to explore optimal indicators for HFVI/ANI-based pain assessment.
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