A discrete event simulation was applied to model the perioperative process in the general surgery service at Toronto General Hospital, aiming at reducing the number of surgical cancellations and improving the perioperative process. This model includes emergency case interruptions with two types of emergency cases with different levels of urgency, and takes into account the availability of three types of post-surgical beds: medical surgical intensive care unit, step-down unit and ward beds in decision making level. The effect of three types of scenarios on the number of surgical cancellations was explored: 1) applying effective scheduling rules based on the utilization of post-surgical beds, 2) sequencing the surgical operations based on the length of surgeries and the variance of surgery durations, 3) increasing the number of post-surgical beds.