In the present study, ASA-PS ≥ 3, qSOFA score ≥ 2, and complications caused by non-surgical therapy were identified as predictors of FTR in SR. In addition, our SRSS stratified the short- and long-term prognoses of SR, suggesting that it may be useful for preoperative risk assessment.
Only a few epidemiological studies on SR have been published to date. Briggs et al. reported that cases of SR accounted for 13% of the inpatient cases treated by an ACS team [9]. In their study, 85% of the SR cases showed complications from surgery, while the remaining 15% showed complications from procedures or endoscopy. In our study, 82 (58%) cases showed surgery-related complications. Kutcher et al. reported that SR was required in 320 (13%) of 2,410 patients who underwent ACS.[4] Among the cases involving SRs, 36% were referred by their own departments, 38% by other departments, and 26% by other hospitals. Moreover, compared with patients in other ACS departments, those requiring SR had longer hospital stays and higher in-hospital mortality rates. However, the definition of SR remains ambiguous. Although SR is considered a remedy for invasive procedures and postoperative complications [4], the details of invasive procedures have not yet been defined. In this study, we included chemotherapy, radiotherapy, and IVR procedures as invasive procedures. Thus, establishing a clear definition of SR is essential.
Ghaferi et al. compared mortality outcomes between hospitals after the following six major surgeries: pancreatectomy, esophagectomy, abdominal aortic aneurysm surgery, coronary artery bypass surgery, aortic valve replacement, and mitral valve replacement [10]. They concluded that complication rates were equal among hospitals, but mortality rates after complications differed and that better management of complications contributed to lower mortality rates. Peitzman et al. reported that more than 80% of patients with SR required surgery, and 50% required multiple surgeries [5]. Moreover, over half of these patients were admitted to the intensive care unit. They reported that a team of experienced surgeons is required to handle many of these complex complications and critical illnesses and that an acute care surgeon should be in charge. Khalil et al. reported that trauma centers staffed by acute care surgeons were more effective in reducing the length of stay, medical costs, and complications in emergency general surgery than regular trauma centers [11]. In our study, the involvement of acute care surgeons in SR did not improve the outcomes. This finding can be attributed to the following reasons. First, acute care surgeons might have treated patients with severe SR. The acute care surgeon group had more referrals from other departments and hospitals, and the qSOFA score in this group was significantly higher. An SRSS score of 2 or 3 was also more common in the acute care surgeon group. In a previous study, Kevin et al. reported that surgeons with more years of experience were entrusted with emergency surgeries for more severely ill patients, such as those with septic shock and renal failure [12]. Second, only one acute care surgeon was involved in the study. The number of acute care surgeons in Japan is small, and increasing the number of such surgeons is important to reduce the rates of FTR in SR.
The ASA-PS [13–15] and qSOFA score [16–18], which were identified as predictors of FTR in SR in this study, have been reported as prognostic factors for other diseases. Sato et al. tested whether the ASA-PS could predict the prognosis of 301 patients with esophageal cancer who underwent esophagectomy [15]. In their study, multivariate analysis identified the ASA-PS as an independent predictor of overall survival (OS) in patients with esophageal cancer. Patients with an ASA-PS of 3 reportedly showed a lower rate of perioperative chemotherapy, which was attributed to longer operative times and greater blood loss in these patients. The authors concluded that more careful perioperative management is needed in patients with an ASA-PS of 3. Endo et al. reported the findings for patients with gastric cancer aged > 80 years who underwent gastrectomy [14]. In their study, an ASA-PS of 3/4 was reported to be an independent predictor of OS. Both reports cited the ASA-PS as a predictor of long-term prognosis after elective surgery. Our study is the first to identify ASA-PS as a predictor of the short-term prognosis of SR, one of the pillars of ACS. Abdullah et al. reported the findings in 434 patients with sepsis diagnosed using the Systemic Inflammatory Response Syndrome criteria [18]. They reported that a qSOFA score of ≥ 2 was an independent prognostic predictor of 30-day mortality. The qSOFA score was proposed as a diagnostic criterion for sepsis in the emergency room in Sepsis-3 [8]. Previous studies have generally reported that the qSOFA score has high specificity and low sensitivity for predicting mortality in patients with sepsis [19]. In this study, we report the importance of the qSOFA score as a prognostic factor for SR. Previous studies have reported the usefulness of the qSOFA score as a prognostic factor in diseases other than sepsis, such as acute pulmonary embolism [20] and idiopathic pulmonary fibrosis [21]. This is the first study to report the utility of the qSOFA score in SR.
Complications caused by non-operative therapy were also identified as predictors of FTR in this study. The results indicated that cases of SR necessitated by non-operative therapy were referred from other departments or hospitals. Kutcher et al. reported that patients from other departments had similar in-hospital mortality and long-term outcomes but worse length of stay and home discharge rates than patients from their department [4]. The complications caused by non-operative therapy might have been a prognostic factor in the present study as well because many patients were referred from other departments and hospitals. The non-surgery group showed a lower BMI, more peritonitis, and lower WBC and Plt counts. This suggests that the non-surgery group might have been in a worse condition than the surgery group.
Only one study of FTR in ACS has been previously reported. Abe et al. reported the complications and in-hospital mortality rates in patients with trauma [7]. The Japan Trauma Data Bank was used in their study, and 184,214 trauma cases were included. They reported lower complication and FTR rates in high-volume trauma centers. Additionally, they emphasized that avoiding trauma deaths, as well as complications, is important to improve the quality of trauma care. This study is the first to report FTR in cases involving SR. The predictors of FTR in SR were qSOFA score ≥ 2, ASA-PS ≥ 3, and complications caused by non-surgical therapy. Moreover, the SRSS based on these predictors can predict the prognosis from the preoperative stage.
This study had some limitations. First, this was a small, single-center, retrospective study. Because the number of cases was only 142, validation through multicenter studies is required in the future. Second, the definition of SR remains ambiguous. The invasive procedures discussed in this study included chemotherapy, radiation therapy, and IVR procedures, as mentioned earlier. In the few reports that were published in the past, IVR was often included as an invasive procedure, but chemotherapy and radiation therapy were not. However, in real-life practice, especially in the field of oncologic emergencies, treatment of complications after chemotherapy and radiotherapy is common, and its administration is expected to increase in the future due to its expanding indications. Therefore, acute care surgeons need to be familiar with these diseases, which is why they were included in the SR in this study. Future studies should aim to develop a clear definition of SR. Third, only one acute care surgeon was involved; therefore, the usefulness of acute care surgeons in SR could not be demonstrated. Although a few reports have described improved prognoses with the involvement of acute care surgeons in SR, this issue needs to be explored in more detail in future studies.