Autonomic nervous system modulation is assessed at four main time: (i) T1 baseline (before the induction of general anesthesia); (ii) T2, 5 min after the induction of general anesthesia, (iii) T3, pneumoperitoneum insufflation (Group A) or steep trendelenburg (Group B); (iv) T4, steep trendelenburg (Group A) or pneumoperitoneum insufflation (Group B).