Watch this video taken during a back surgery on a 13-year-old. At 00:04 there is an ANI value of 94 and a good ECG signal with a wide respiratory pattern, indicating the predominance of the parasympathetic tone of the patient (HFnu). This means that the patient is comfortable and unconscious and with no stimulation. The energy value of 0,1 shows a very low autonomic activity function, blunted by the general anesthesia provided. However, we still do not know if the analgesics administered are enough or not to avoid the stimulation of the incision. A heart rate of 84 and a BIS of 54 confirms that the patient is unconscious. At 00:43, the respiratory pattern is completely flat, covering only around 10% percent of the area. This means that nearly all autonomic activity is sympathetic due to the incision (low HFnu). The sympathetic predominance is also seen by the heart rate increases to 111 bpm and the raising of the energy value of 2,04, referring to high autonomic activity. In this case, we can conclude that analgesia is required as the ANI value will certainly drop because we have seen previously a decrease in the respiratory pattern. The patient did not have enough analgesia coverage to control the stimulation, so a bolus of ketamine is required, however, we need to take into account that it will last around 7 min to make its effect.