The role of intraoperative real-time nociceptive monitoring in individualised anaesthesia and analgesia and where to head next; A narrative review

Acute postoperative pain remains common despite advances in surgical techniques and enhanced recovery protocols, suggesting that patient-specific factors and individualised approaches may be key to improving outcomes. Real-time intraoperative nociceptive monitoring has emerged as a potential tool to guide analgesia and predict postoperative pain bur their role in an individualised anaesthesia framework is unclear. This narrative review qualitatively evaluates the evidence for various intraoperative nociception monitors within the conceptual framework of individualised anaesthesia and analgesia, aiming to identify promising methods and highlight knowledge gaps. Literature on real-time nociception monitoring devices, including Analgesia Nociception Index, Surgical Pleth Index, Nociception Level Index, pupillometry, skin conductance, processed EEG and Quantum Nociception Index was reviewed for physiologic rationale, intraoperative performance, and predictive validity for intraoperative opioid consumption, postoperative pain intensity and postoperative opioid consumption. All monitors are based on physiologically plausible surrogates of nociception, primarily autonomic or neurophysiologic responses. Evidence suggests these devices can influence intraoperative opioid titration, but their predictive accuracy for postoperative pain is modest and inconsistent. Confounders such as anaesthetic depth, vasoactive drugs, and patient variability limit specificity. Pooled data and randomised trials show small or no clinically meaningful improvements in postoperative outcomes. Multimodal approaches and integration with anaesthesia depth monitoring may enhance utility, but robust, procedure-specific protocols are lacking. Current real-time nociception monitors should be considered adjuncts rather than standalone tools. Their role in individualised anaesthesia remains theoretical until validated algorithms and high-quality trials demonstrate not only guidance in intraoperative opioid administration but also improvement in recovery and reduction of postoperative pain.