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Updated: Feb 15, 2026

Objective Nociceptive Assessment in Ventilated ICU Patients: A Feasibility Study Using Pupillometry and the Nociceptive Flexion Reflex
Published on: July 4, 2018
Development, validation and utility of a simulation model of the nociceptive flexion reflex threshold
Carlo Jurth1, Teresa M Dörig2, Gregor Lichtner2
1Charité - Universitätsmedizin Berlin, Klinik für Anästhesiologie mit Schwerpunkt Operative Intensivmedizin, Campus Charité Mitte und Campus Virchow-Klinikum, Berlin, Germany. Electronic address: https://www.charite.de.
Objective:
A variety of algorithms is used for nociceptive flexion reflex threshold (NFRT) estimation, but their estimation accuracy is unknown. We developed a computer based simulation model of the NFRT to quantify and compare the accuracy of available estimation algorithms.
Methods:
This simulation model is based on basic characteristics of the NFRT and specified by data collected from 60 healthy volunteers. We validated the model by comparing simulated data with data obtained independently in another volunteer population. The model was used to quantify the accuracy of previously published NFRT estimation algorithm for three NFRT variabilities representing sensory deprivation, distraction and general anaesthesia.
Results:
The dynamic staircase algorithm obtained most accurate NFRT estimates during all NFRT variabilities. The number of stimuli applied can be chosen higher to increase estimate precision or lower to reduce measurement time.
Conclusions:
Our simulation model is a valid tool to measure the accuracy of NFRT estimation algorithms. It can be applied to analyse and develop algorithms. The dynamic staircase algorithm shows the highest precision in NFRT estimation and is recommended for NFRT studies.
Significance:
Using optimized NFRT estimation algorithms increases precision in clinical and experimental NFRT studies and might therefore reduce the measurement effort necessary.
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