The prevalence of sepsis in the last 30 years has been reported to range from 21.7–51.5% of all patients admitted to the ICU [10, 11], about 30–42.8% community-acquired pneumonia associated sepsis [2, 3, 11, 12], with a mortality rate of 23–48.2% in the ICU [2, 3, 11], 81.7% of septic patients with delirium in the ICU develop acute respiratory distress syndrome (ARDS), requiring intubation and mechanical ventilation . Although sepsis has been frequently studied, its clinical features and risk factors of patients who were non-survivors still need clarification. Undoubtedly, early diagnosis and treatment can reduce the mortality of sepsis. In the present study, so we used quick diagnosis tests, including early systemic CT scans and quick clinical tests to screen infection and sepsis. We found that the features of sepsis were mainly from community-acquired sepsis (73.8%), and most of them with community-pneumonia (78.3%). These data are higher than previous study , and the features are similar to the current outbreak of COVID-19 sepsis [9, 15].
More importantly, we found that acute respiratory failure/ARDS (93.5%) and acute brain failure (94.4%) were the most common life-threatening organ dysfunctions in most of the sepsis cases, with a 55.6% risk of death within the initial 28 days in the ICU.
It should be noted, however, that critically ill ICU patients with sepsis with a high risk of death in our study were more likely to present with a higher SIRS score, a higher SOFA score, a higher qSOFA score, elevated interleukin-6, elevated D-dimer, lower GCS score and lower SpO2, elevated CRP and procalcitonin, elevated creatinine, elevated blood glucose, and elevated lactic acid. Notably, by multivariate regression analysis, only higher SIRS scores and higher SOFA scores (MODS) were related to high mortality in critically ill patients with sepsis.
Several possible interpretations of the results for sepsis with high mortality are as follows. First, MODS due to sepsis resulting in high mortality has been recognized [4, 14, 16–19], and previous studies have shown that sepsis patients with MODS are more likely to exhibit ARDS [4, 17–19] and acute brain dysfunction [13, 20–22], which is related to their vulnerability to hypoxia/SIRS [7, 13, 19–22]. Our data showed that current sepsis had MODS and that over 90.0% of patients with sepsis had acute respiratory failure/ARDS. The features of ARDS are mainly acute pneumonia/pulmonary infection due to a dysregulated immune response leading to higher inflammation in the lungs, followed by the development of pulmonary edema, hyaline membrane formation, and respiratory failure [19, 23]. Moreover, acute respiratory failure/ARDS plays a pivotal role in the development of MODS in septic events [7, 13, 14, 18]; epithelial damage and SIRS are the main pathophysiological features of ARDS and play an important role in distinguishing the hyperinflammatory subtypes of ARDS  .
Another possibility is that acute brain failure is also ranked as the leading organ dysfunction and for the host response to hyperinflammation, which is more likely to be due to hypoxic/SIRS [13, 14, 16, 20–22], especially with a cause of acute pneumonia/pulmonary infection [14, 17, 18]. Similar to the current outbreak of COVID-19 pneumonia, the mechanisms of bacterial pneumonia are also related to angiotensin conversion enzyme 2 (ACE2)- involved inflammatory response/cascade [24, 25]. Furthermore, blood- brain barrier (BBB) leakage is also due to an overwhelming release of proinflammatory cytokines and anti- inflammatory factors [26–28]. SIRS is responsible for extensive BBB leakage and even brain edema and cerebral ischemic injury as well as cell death [26–29]. Our current study confirmed that SIRS is a very high risk factor for dying from sepsis, supporting that it is a life-threatening systemic inflammatory syndrome [8, 30].
Strengths in this study, we are a first to report that a brain-chest-abdomen CT scan before arriving at the hospital to identify early infection site which is a visible really infection. Severe SIRS and severe lungs/brain failure could use to predict the risk of sepsis with worse outcomes,
However, some limitations of our design must be addressed. One limitation is the single central design, which may present a selection bias. However, this hospital is responsible for the medical care of the prefecture's population of approximately 1.8 million people, including an urban center and 38 villages and towns. This hospital ICU is a unique regional ICU (open 21-bed) with an emergency center (a total of 10 ambulances) that is responsible for all critically ill referrals in this prefecture. Thus, we believe that this sample does not lead to a large bias. The second limitation of this study is that organ dysfunction meeting the SOFA criteria was evaluated only according to old criteria. Although we made some changes, the observed SOFA scores may still be underestimated. In addition, although the prognosis for sepsis was related to SIRS and MODS, further prospective multicenter studies are needed for some of the intermediary links.