Fig 1

Definition of post-induction period and timing of blood pressure measurement. We defined post-induction period as the initial 60-min period taking place immediately after anesthesia induction. Starting anesthesia (0 min) was initiation of anesthesia induction. If a positional change from a supine to a prone or lateral recumbent position was performed during this 60 min in craniotomy, the study period was then defined as the time from anesthesia induction to just before the positional change. ALA, 5-aminolevulinic acid; OR, operating room; BP1, blood pressure before 5-ALA intake; BP2, blood pressure when entering operating room (before anesthesia induction); BP3, blood pressure during post-induction period