1992年共识会，定义脓毒症为当患者符合两个全身性发炎反应综合征（systemic inflammatory response syndrome，SIRS）且怀疑这些症状是因为感染所造成。2016年第三次国际脓毒症既脓毒症休克共识会，定义脓毒症为宿主对感染的失调反应导致危及生命的器官功能障碍，诊断脓毒症的临床条件为当患者在怀疑或确定感染的前提下，器官衰竭评估分数（sequential organ failure assessment，SOFA）急速增加超过2分。定义脓毒性休克为一部分脓毒症的患者，出现严重的循环障碍及细胞代谢异常，导致病死率显著增加，诊断标准为脓毒症患者，在充分补充血容量后，仍需要升压药物以维持平均动脉压≥65 mmHg（1 mmHg=0.133 kPa）且血清乳酸水平＞2 mmol/L。并提出快速器官衰竭评估（quick SOFA，qSOFA）即神志改变，收缩压≤100 mmHg，或呼吸频率≥ 22次/min，患者符合两个qSOFA条件时，即应怀疑脓毒症进入重症病房观察。

作为一个医院管理者及脓毒症流行学者，新版定义为在ICU外的医护人员提供一个简洁的方法，快速筛选出脓毒症患者，进行积极治疗，增进照顾质量，新版定义除了专家意见外，运用流行病学的方法，以患者是否死亡或需要＞ 3 d ICU治疗作为结果指标，测试新定义的效度，新定义在预测死亡能力比SIRS高。在进行临床试验及流行病调查时，使用新版的脓毒症定义与我们最关心的终点——病死率有较好的相关，同时避免脓毒症与严重脓毒症定义不同所造成的混淆。

A 1991 consensus conference defined sepsis as a host?s systemic inflammatory response syndrome (SIRS) to infection. The Third International Consensus Definitions for Sepsis and Septic Shock in 2016 defined Sepsis as a life-threatening organ dysfunction caused by a dysregulated host response to infection. Clinical criteria to identify patients with Sepsis are suspected or documented infection and an acute increase of ≥2 SOFA points (a proxy for organ dysfunction). Screening for patients likely to have Sepsis is using clinical scoring system termed quickSOFA (qSOFA): respiratory rate of 22/min or greater, altered mentation, or systolic blood pressure of 100mmHg or less. Septic shock is a subset of Sepsis in which underlying circulatory and cellular/metabolic abnormalities are profound enough to substantially increase mortality. Clinical criteria to identify septic shock are Sepsis with a necessary vasopressor therapy to elevate MAP ≥65 mm Hg and lactate >2 mmol/L (18 mg/dL) despite adequate fluid resuscitation.

As a hospital administrator and Sepsis epidemiology researcher, I agree with the new definition. The new definition offered a simple method for medical practitioners outside ICU to recruit potential sepsis patients for early aggressive intervention. The consensus for this definition was developed using death or over 3 days ICU stay as an end point and was validated in several Sepsis database. For clinical trial and epidemiology studies, the new Sepsis definition has a better predictive validity for death than SIRS and avoids the confusion of Sepsis and Severe Sepsis.