急性呼吸窘迫综合征的发病率约为64/100 000,美国每年发病190 000例,此发病率比原先估计高2~40倍,产生原因并非发病率上升,而是原先被低估。[2]Rubenfeld GD, Caldwell E, Peabody E, et al. Incidence and outcomes of acute lung injury. N Engl J Med. 2005;353:1685-1693.http://www.ncbi.nlm.nih.gov/pubmed/16236739?tool=bestpractice.com总之,10%~15%的ICU患者和20%的机械通气患者符合急性呼吸窘迫综合征的诊断标准。[3]Frutos-Vivar F, Esteban A. Epidemiology of acute lung injury and acute respiratory distress syndrome. Curr Opin Crit Care. 2004;10:1-6.http://www.ncbi.nlm.nih.gov/pubmed/15166842?tool=bestpractice.com欧洲、澳大利亚和其他发达国家的急性呼吸窘迫综合征的发病率为17~34/100 000/年,略低于美国报告的水平。[4]MacCullum NS, Evans TW. Epidemiology of acute lung injury. Curr Opin Crit Care. 2005;11:43-49.http://www.ncbi.nlm.nih.gov/pubmed/15659944?tool=bestpractice.com危重病、吸烟和饮酒是急性呼吸窘迫综合征的诱发因素。[5]Moss M, Parsons PE, Steinberg KP, et al. Chronic alcohol abuse is associated with an increased incidence of acute respiratory distress syndrome and severity of multiple organ dysfunction in patients with septic shock. Crit Care Med. 2003;31:869-877.http://www.ncbi.nlm.nih.gov/pubmed/12626999?tool=bestpractice.com性别、种族和人种与急性呼吸窘迫综合征发病率无关。
急性呼吸窘迫综合征的病死率接近40%,在美国每年导致约75 000人死亡。[2]Rubenfeld GD, Caldwell E, Peabody E, et al. Incidence and outcomes of acute lung injury. N Engl J Med. 2005;353:1685-1693.http://www.ncbi.nlm.nih.gov/pubmed/16236739?tool=bestpractice.com尽管病死率在大型临床试验看来似乎是稳步下降。[6]Erickson SE, Martin GS, Davis JL, et al. Recent trends in acute lung injury mortality: 1996-2005. Crit Care Med. 2009;37:1574-1579.http://www.ncbi.nlm.nih.gov/pubmed/19325464?tool=bestpractice.com轻度(200<氧合指数≤300)、中度(100<氧合指数≤200)和重度(氧合指数≤100)的区别在于临床预后不同。[1]ARDS Definition Task Force; Ranieri VM, Rubenfeld GD, Thompson BT, et al. Acute respiratory distress syndrome: the Berlin definition. JAMA. 2012;307:2526-2533.http://www.ncbi.nlm.nih.gov/pubmed/22797452?tool=bestpractice.com