Pain Detection with Bioimpedance Methodology from 3-Dimensional Exploration of Nociception in a Postoperative Observational Trial

Abstract

Although the measurement of dielectric properties of the skin is a long-known tool for assessing the changes caused by nociception, the frequency modulated response has not been considered yet. However, for a rigorous characterization of the biological tissue during noxious stimulation, the bioimpedance needs to be analyzed over time as well as over frequency. The 3-dimensional analysis of nociception, including bioimpedance, time, and frequency changes, is provided by ANSPEC-PRO device. The objective of this observational trial is the validation of the new pain monitor, named as ANSPEC-PRO. After ethics committee approval and informed consent, 26 patients were monitored during the postoperative recovery period: 13 patients with the in-house developed prototype ANSPEC-PRO and 13 with the commercial device MEDSTORM. At every 7 min, the pain intensity was measured using the index of Anspec-pro or Medstorm and the 0–10 numeric rating scale (NRS), pre-surgery for 14 min and post-anesthesia for 140 min. Non-significant differences were reported for specificity-sensitivity analysis between ANSPEC-PRO (AUC = 0.49) and MEDSTORM (AUC = 0.52) measured indexes. A statistically significant positive linear relationship was observed between Anspec-pro index and NRS (r2 = 0.15, p < 0.01). Hence, we have obtained a validation of the prototype Anspec-pro which performs equally well as the commercial device under similar conditions.

Bioimpedance Sensor and Methodology for Acute Pain Monitoring

“…Beside tests within controlled laboratory environments, the second generation device was clinically validated by means of a comparison with a reference commercial device, both methodologies based on electrodermal activity identification. The observational study in awake postoperative patients concluded that Anspec-PRO performs equally well as the commercial device under similar conditions, representing proof of concept for the prototype device [20]. Moreover, Anspec-PRO is currently under tests in a clinical trial on anesthetized patients for its validation in surgery context, in comparison to other two commercial pain monitors.…”

“…The already available results indicate that the developed prototype is able to capture the signaling pathways and deliver an objective measure for pain. A clinical trial was conducted in patients recovering from anesthesia, and the results show a good performance for the prototype to identify changes in pain pathways by measuring the skin impedance [20]. As the aim of this paper is to illustrate the development methodology of our prototype, the existing prior results with more details about the previous work can be found in Section 3.7.…”

“…The existence of a memory effect is proven from measured data [18]. • Spectrographic analysis of the skin impedance measured with second Anspec-PRO device was approached to obtain a wider view towards the signal [20].…”

An Open Source Patient Simulator for Design and Evaluation of Computer Based Multiple Drug Dosing Control for Anesthetic and Hemodynamic Variables

“…A PD model for analgesia as a separate output variable to be controlled is currently missing. Presently, enabled by recent commercial devices availability for objective pain level assessment, ongoing efforts in clinical trial testing [72], [73] are expected to provide the necessary data for estimating the PD model. The hemodynamic system is described as a first order plus dead time approximation of the PKPD effects.…”

“…Hence, there is no pharmacodynamic model for Remifentanil. In this regard, the authors developed a methodology for detecting nociceptor simulation which has been successfully validated in healthy volunteers [50] but also in post-operative ICU patients [73]. Ongoing clinical studies in unconscious patients at Ghent University Hospital will provide updates for future versions of the simulator.…”