Acute appendicitis is the most common surgical emergency seen in emergency departments. Timely access to acute emergency surgery is important for patients’ outcomes and there are numerous factors that contribute to poor outcomes such as a shortage of surgeons, inadequate numbers of emergency ORs, and the lack of an emergency team.  The ACS system was introduced to serve as a solution for the problem of a lack of a dedicated emergency surgeon. The United States introduced it in the early 2000s and it is systematically being implemented in several areas, including trauma centers and surgical ICUs. Recently, several studies on the impact of the implementation of the ACS system have been published, one paper reported that, compared to the TROS, the ACS system lowered the mortality and complication rates, and reduced the time to operation and financial costs. A meta-analysis of 27 studies that included 744,000 patients with emergency surgical diseases such as acute appendicitis, acute cholecystitis, and inguinal hernia, reported that the application of the ACS system had improved the clinical and financial outcomes for emergency general surgery.  Additionally, according to several previous reports, when comparing and analyzing general surgical conditions such as acute appendicitis and acute cholecystitis, the times taken to get from the ER to the OR and postoperative complication rates were reduced after the introduction of the ACS system. [11-13] In our study, with the implementation of the ACS, the median length of hospital stay was reduced by 3 days; however, this was not explained by the introduction of the ACS system alone. Before the introduction of the ACS system, the clinical pathway (CP) that was used to treat hospitalized patients was not uniform and patients were managed by different surgeons from various surgical divisions; however, with the introduction of this system, we created a unified CP for the management of acute appendicitis. To prevent unnecessary antibiotic abuse, delay of diet proceedings, and unnecessary X-ray and laboratory evaluations, the admission and discharge periods, and the use of antibiotics according to the grade of the acute appendicitis were determined in advance. This was a difficult task to perform with the TROS.
The times taken to get from the ER to the OR, which were expected to have an effect in this study, did not differ between the 2 groups. After the introduction of the ACS system, the ACS surgeon is always on-call, which allows for surgical decisions to be made, as well as for the treatment plan to be determined as soon as possible. However, in order to perform the surgeries, various components relating to personnel and materials such as the OR, anesthesiologist, and nurse, in addition to the surgeon, must be prepared on-call. In order to shorten the time taken to get from the ER to the OR, it is necessary to prepare the on-call team and facilities (such as the anesthesiologist, OR, and scrub nurse), as well as the ACS surgeon, for emergency surgery.
Although, at our center, complicated operations, such as right hemicolectomy were performed to a greater extent in the post-ACS group, there were no differences in the rates of the postoperative complications between the 2 groups. Regarding acute appendicitis, only simple appendectomies were performed in more than two-thirds of the cases, the possibilities of severe complications were low, and the course of the disease was benign, so acute appendicitis itself is not considered a disease that greatly affects the mortality or morbidity of the patients. We considered that this may have a greater effect on outcomes such as the length of hospital stay than the rates of postoperative complications or mortality, as in our study.
This study has some limitations. First, it was a retrospective study, which may have been a source of selection bias. Second, the medical environment in South Korea is unique. In South Korea, since medical care is relatively inexpensive, patients tend to remain hospitalized for no specific reason, which limits the ability to base the evaluation of the length of hospital stay solely on the effect of the ACS system. Third, our study did not analyze the hospital costs. Other studies reported that the ACS system resulted in a reduction in the hospital costs. (10,12) However, in South Korea, medical expenses for acute appendicitis are calculated and paid for in advance, so there are no significant differences in the medical expenses. Therefore, we did not perform a cost analysis in this study.