Loss of spectral alpha power during spine surgery: what could be wrong?

The electroencephalographic signatures of anesthetic drugs relate to a specific set of action mechanisms within the neural circuits. During intraoperative care, the recognition and correct interpretation of the EEG spectrogram can be used as a tool to guide anesthetic administration. For example, loss of alpha power during propofol anesthesia may be a sign of lighter level of hypnosis and/or of an increase in nociceptive inputs. We describe a case report of inadvertent interruption of propofol delivery that was first detected by changes in the electroencephalogram spectrogram.