Analgesia Nociception Index (ANI) to predict intraoperative haemodynamic changes: results of a pilot investigation

Background The Analgesia Nociception Index has been described to reflect different levels of intraoperative nociceptive stimulation during total intravenous anaesthesia. The association between this index and haemodynamic changes during sevoflurane-based anaesthesia was investigated in 30 patients with the hypothesis that changes in the Analgesia Nociception Index may coincide with or even predict haemodynamic changes. Methods The Analgesia Nociception Index as well as blood pressure and heart rate were observed during induction, at skin incision, at times of an Analgesia Noceception Index decrease > 20% (‘event’) and pre-/post-fentanyl administration. Results The Analgesia Nociception Index decreased with airway manipulation [mean: 52 (before) vs. 33 (after); P 10% was low (heart rate 0.61; blood pressure 0.59). Conclusions The Analgesia Nociception Index appears to reflect different levels of stimulation during sevoflurane-based general anaesthesia. However, it was of little predictive value to pre-empt significant haemodynamic changes.