Depth of Anesthesia and Nociception Monitoring: Current State and Vision For 2050

Abstract

Anesthesia objectives have evolved into combining hypnosis, amnesia, analgesia, paralysis, and suppression of the sympathetic autonomic nervous system. Technological improvements have led to new monitoring strategies, aimed at translating a qualitative physiological state into quantitative metrics, but the optimal strategies for depth of anesthesia (DoA) and analgesia monitoring continue to stimulate debate. Historically, DoA monitoring used patient’s movement as a surrogate of awareness. Pharmacokinetic models and metrics, including minimum alveolar concentration for inhaled anesthetics and target-controlled infusion models for intravenous anesthesia, provided further insights to clinicians, but electroencephalography and its derivatives (processed EEG; pEEG) offer the potential for personalization of anesthesia care. Current studies appear to affirm that pEEG monitoring decreases the quantity of anesthetics administered, diminishes postanesthesia care unit duration, and may reduce the occurrence of postoperative delirium (notwithstanding the difficulties of defining this condition). Major trials are underway to further elucidate the impact on postoperative cognitive dysfunction. In this manuscript, we discuss the Bispectral (BIS) index, Narcotrend monitor, Patient State Index, entropy-based monitoring, and Neurosense monitor, as well as middle latency evoked auditory potential, before exploring how these technologies could evolve in the upcoming years. In contrast to developments in pEEG monitors, nociception monitors remain by comparison underdeveloped and underutilized. Just as with anesthetic agents, excessive analgesia can lead to harmful side effects, whereas inadequate analgesia is associated with increased stress response, poorer hemodynamic conditions and coagulation, metabolic, and immune system dysregulation. Broadly, 3 distinct monitoring strategies have emerged: motor reflex, central nervous system, and autonomic nervous system monitoring. Generally, nociceptive monitors outperform basic clinical vital sign monitoring in reducing perioperative opioid use. This manuscript describes pupillometry, surgical pleth index, analgesia nociception index, and nociception level index, and suggest how future developments could impact their use. The final section of this review explores the profound implications of future monitoring technologies on anesthesiology practice and envisages 3 transformative scenarios: helping in creation of an optimal analgesic drug, the advent of bidirectional neuron-microelectronic interfaces, and the synergistic combination of hypnosis and virtual reality.

Transformative Landscape of Anesthesia Education: Simulation, AI Integration, and Learner-Centric Reforms: A Narrative Review

“…Currently, many monitors automatically analyze parameters like respiratory rate and electrocardiogram waveforms, alerting us to potential abnormalities. Anesthesia monitoring alarms are currently based on individual values such as blood pressure and percutaneous oxygen saturation, but systems such as arterial pressure cardiac output measurement have been introduced, estimating vascular volume from calculated values [19,20]. However, there are challenges in the current stage regarding the integration of various information.…”

Correlation of Comfort Score and Narcotrend Index during Procedural Sedation with Midazolam and Propofol in Children

“…Contrarily, the continuous monitoring of electrocortical activity provides uninterrupted information on sedation levels without the need to apply such a stimulus. It is generally acknowledged that anesthesia-induced changes of processed EEG provide information on the hypnotic depth [ 13 , 14 , 15 ]. A long-established technique in this context is the bispectral index (BIS), which provides a dimensionless number between 0 and 100 derived from hemifrontal EEG independent of the patients’ age.…”

When nociception monitoring becomes predictive of surgical outcomes : has the future already become real ?

“…Perfect control of nociception during general anesthesia may one day enable patients to express no “response to surgical stress” during surgery. Despite some progress in the field of nociception monitoring, this future may be some decades away, and the clinical benefits of an absence of response to stress still needs to be outlined, as one can only suppose that it would result in less hemodynamic impairment, organ dysfunction, digestive malfunction, cognitive impairment, acute and chronic post-operative pain… [ 1 ].…”