The Revised Atlanta Classification 2012 defined three degrees of severity of AP: mild AP (MAP), moderate severe AP (MSAP), and SAP. SAP is characterized by persistent organ failure (greater than 48 hours). Patients with AP complicated with multiple organ dysfunction syndromes (MODS) are considered to have SAP. SAP is an extremely dangerous condition, and the in-hospital mortality rate of SAP in China is 11.8% . Early identification of SAP is necessary to reduce the mortality rate of patients with AP .
Currently, there are a number of scoring systems and indicators for assessing the severity of AP. Ranson's score is one of the most widely used clinical prognostic scores. A Ranson’s score of ≥ 3 have a better sensitivity for the diagnosis of SAP . However, Ranson's score can not be used for all populations. YANG et al. showed that Ranson’s score has no significant advantage in predicting the severity and prognosis of hyperlipidemic acute pancreatitis (HLAP) , and Ranson’s score can only be determined after 48 hours of admission, the 48-hour delay in predicting the disease condition may lead to delayed fluid resuscitation and delayed interventions for treatment of complications, and rapid identification of SAP cannot be achieved. APACHEⅡ score is the most widely accepted and used scoring system, and is also a highly recommended scoring system by many guidelines . SAP can be diagnosed when patients had an APACHEⅡ score of > 8, and those patients need to be transferred to ICU . Study had shown that APACHE II score is a reliable scoring system, and has high sensitivity for assessing the severity, organ failure and death in AP . However, the APACHEⅡ score can only be determined after 24 hours of admission, and it is a complex system which includes many indicators, and highly depends on laboratory test results, so dynamic determination of disease severity is difficult. BISAP is one of the most accurate and applicable scoring systems in predicting severity, death, and organ failure of patients with AP . BISAP score ≥ 3 is considered SAP, the specificity of BISAP score in predicting SAP is comparable to RANSON’s score , and the ability of BISAP score in predicting severity, infectious pancreatic necrosis and mortality rates in AP are comparable to the APACHE II score , and BISAP score is easier to calculate. However, this scoring system mainly depends on laboratory indicators, which can not achieve a rapid assessment of SAP. According to the Balthazar's CT score, AP was classified into five grades (A to E), which can evaluate the organ failure in patients with AP . CTSI and the modified CT severity index (MCTSI) include the degree of pancreatic necrosis based on the Balthazar score, which are widely used imaging scoring systems. Enhanced CT score (CECT) has a higher sensitivity in assessing the severity of the disease . However, in order to dynamic monitoring, patients have to undergo numerous CT scans and pay high examination costs. And some patients cannot take dynamic CT examinations due to their inability to move themselves. It has been reported that the CT evidence of SAP lags behind clinical outcomes . One certain shortcoming of CTSI, MCTSI, and CECT is the low reproducibility. JSS includes 9 risk factors and enhanced CT examination scores with relatively high accuracy, which is considered to be the best scoring system for the prediction of organ failure in patients with AP , but JSS completely depends on the results of laboratory tests and physical examinations, the feasibility of dynamic assessment of SAP by JSS is relatively low. The modified early warning score (MEWS) can independently predict the poor prognosis and mortality rates of AP patients . MEWS score has the advantages of convenience and non-invasiveness, which can be calculated timely, but MEWS is based on seven indicators, these scores are relatively complex, it is difficult for clinicians to remember with poor compliance. Sequential organ failure (SOFA) is a scoring system used to assess organ function in patients with AP, which can effectively predict severity and mortality of AP, but SOFA score requires multiple laboratory tests, which can increase the suffering and economic burden in patients. And it is difficult to remember and complex to score, this limits the compliance of the clinicians. Although the sensitivity and specificity of the above scoring systems or indicators have been partially confirmed, but most of them are more complex to use and do not provide an early assessment of AP . At present, laboratory indicators such as C-reactive protein, blood urea nitrogen, and hematocrit have been used for predicting SAP , and have certain predictive value, but too many factors can influence the levels of the above laboratory indicators, laboratory tests are expensive and those indicators are difficult to obtain, so those laboratory indicators may not predict SAP accurately. Some biomarkers such as regulator of calcineurin1, Pentraxin-3, cyclophilin A, microRNA (miRNA), soluble CD73, oleic acid chlorohydrin both have the potential to predict SAP, but those biomarkers have not been used in the clinical practice . As mentioned above, the scoring systems and laboratory indicators currently used to predict SAP both have disadvantages, which may limit their clinical use . Developing a simple, convenient, highly reproducible tool for rapid identification of SAP is needed.
In the present study, we used the simplest and easy-to-obtain indicators to design a rapid identification scoring system for SAP. Logistic regression analysis showed that the history of PE, HR, and RR were independent risk factors for SAP with cutoff values of 0.5, 95.5, 22.5, respectively. The RISAP score was designed according to the cutoff values of the three risk factors, 0 and 1 point were assigned for each indicator, the highest score is 3 and the lowest score is 0. HR and RR of patients were measured under adequate analgesia, quietness conditions at admission, pleural effusion can be detected by Doppler ultrasound, CT, bedside evaluation or physical examination. The new designed RISAP score has the ability to predict disease severity timely, it is also simple to use and easy to remember. And in the present study, we used the RISAP score to predict SAP in patients with AP, we found that the RISAP score was significantly higher in the SAP group than that in the non-SAP group, indicating that RISAP can reflect the severity of the AP. When RISAP score ≥ 2, the AUC, sensitivity and specificity of RISAP in predicting SAP is 0.892 (0.842, 0.941), 79.70%, and 96.30%, respectively. Compared with RANSON and BISAP scores, RISAP has the highest AUC, sensitivity and specificity. The results indicated that RISAP score is superior in the prediction of SAP.
If patients present with deep sighing respiration or respiratory arrest, it is obvious that the patients are in critical condition, and emergency treatment for sudden cardiac arrest should be adopted, so RISAP score is not suitable to use in those patients. If HR is greater than 180 beats/min or less than 40 beats/min, those patients were considered to have critical cardiac illness, who were not considered to develop SAP. RISAP is also not suitable to use in patients presenting with tuberculous pleurisy, heart failure, and pleural bleeding, and PE that is not caused by AP. And RISAP score may not be appropriate for patients with pancreatic trauma, pancreatic tumors, cirrhosis, uremia or immunodeficiency, which is also not suitable for infants and children.
The limitation of the present study is that during the first design phase, only 280 patients with SAP from three center of Qiandongnan Miao and Dong Autonomous Prefecture were included, this may introduce bias in the results in terms of cutoff values of identified risk factor, For other regions and other races, the practicability of this scoring system needs further research.