Effect of Ketamine on the Bispectral Index, Spectral Edge Frequency, and Surgical Pleth Index During Propofol-Remifentanil Anesthesia: An Observational Prospective Trial. - Linassi F; Troyas C; Kreuzer M; Spanò L; Burelli P; Schneider G; Zanatta P; Carron M (Anesthesia and analgesia, 2025)