背景:与COVID-19相关的急性呼吸窘迫综合征(ARDS)相比,在其他人群中具有特定的特征。建议与其他形式的ARDS类比,但是关于其在该人群中的生理影响的数据很少。本研究旨在评估分词对氧合参数(PaO2/FiO2和肺泡动脉梯度(Aa梯度))的影响,血气分析,通气比(VR),呼吸系统顺应性(CRS)和估计死腔分数(VD/VTHB)。我们还寻找与治疗失败相关的变量。
方法:对COVID-19ARDS患者进行早期插管的回顾性单中心研究,2020年3月6日至4月30日住院的低至中度呼气末正压和早期治疗策略。血气分析,PaO2/FiO2,Aa梯度,VR,使用配对t检验或Wilcoxon检验(p<0.05被认为是显着的),在每次练习之前和结束时比较CRS和VD/VTHB。使用Fischer精确检验或卡方检验评估比例。
结果:42名患者共纳入191次练习,中位持续时间为16(5-36)小时。考虑到所有会议,PaO2/FiO2增加(180[148-210]vs107[90-129]mmHg,p<0.001)和Aa梯度降低(127[92-176]vs275[211-334]mmHg,p<0.001)与正词。CRS(36.2[30.0-41.8]vs32.2[27.5-40.9]ml/cmH2O,p=0.003),VR(2.4[2.0-2.9]vs2.3[1.9-2.8],p=0.028)和VD/VTHB(0.72[0.67-0.76]vs0.71[0.65-0.76],p=0.022)略有增加。考虑到第一次练习,PaO2/FiO2增加(186[165-215]vs104[94-126]mmHg,p<0.001)和Aa梯度降低(121[89-160]vs276[238-321]mmHg,p<0.001),而CRS,VR和VD/VTHB不变。在随后的发音过程中观察到类似的变化。在经历治疗失败(定义为ICU死亡或需要体外膜氧合)的患者中,较少的人在氧合方面表现出积极的反应(定义为PaO2/FiO2增加超过20%)对第一次出现(67对97%,p=0.020)。
结论:如果我们一起考虑所有疗程,则在COVID-19ARDS插管的患者中练习会导致PaO2/FiO2升高和Aa梯度降低,第一个或随后的4个独立会话。在考虑所有会议时,CRS增加,VR和VD/VTHB仅略有增加。
BACKGROUND: COVID-19 related acute respiratory distress syndrome (ARDS) has specific characteristics compared to ARDS in other populations. Proning is recommended by analogy with other forms of ARDS, but few data are available regarding its physiological effects in this population. This study aimed to assess the effects of proning on oxygenation parameters (PaO2/FiO2 and alveolo-arterial gradient (Aa-gradient)), blood gas analysis, ventilatory ratio (VR), respiratory system compliance (CRS) and estimated dead space fraction (VD/VT HB). We also looked for variables associated with treatment failure.
METHODS: Retrospective monocentric study of intubated COVID-19 ARDS patients managed with an early intubation, low to moderate positive end-expiratory pressure and early proning strategy hospitalized from March 6 to April 30 2020. Blood gas analysis, PaO2/FiO2, Aa-gradient, VR, CRS and VD/VT HB were compared before and at the end of each proning session with paired t-tests or Wilcoxon tests (p < 0.05 considered as significant). Proportions were assessed using Fischer exact test or Chi square test.
RESULTS: Forty-two patients were included for a total of 191 proning sessions, median duration of 16 (5-36) hours. Considering all sessions, PaO2/FiO2 increased (180 [148-210] vs 107 [90-129] mmHg, p < 0.001) and Aa-gradient decreased (127 [92-176] vs 275 [211-334] mmHg, p < 0.001) with proning. CRS (36.2 [30.0-41.8] vs 32.2 [27.5-40.9] ml/cmH2O, p = 0.003), VR (2.4 [2.0-2.9] vs 2.3 [1.9-2.8], p = 0.028) and VD/VT HB (0.72 [0.67-0.76] vs 0.71 [0.65-0.76], p = 0.022) slightly increased. Considering the first proning session, PaO2/FiO2 increased (186 [165-215] vs 104 [94-126] mmHg, p < 0.001) and Aa-gradient decreased (121 [89-160] vs 276 [238-321] mmHg, p < 0.001), while CRS, VR and VD/VT HB were unchanged. Similar variations were observed during the subsequent proning sessions. Among the patients who experienced treatment failure (defined as ICU death or need for extracorporeal membrane oxygenation), fewer expressed a positive response in terms of oxygenation (defined as increase of more than 20% in PaO2/FiO2) to the first proning (67 vs 97%, p = 0.020).
CONCLUSIONS: Proning in COVID-19 ARDS intubated patients led to an increase in PaO2/FiO2 and a decrease in Aa-gradient if we consider all the sessions together, the first one or the 4 subsequent sessions independently. When considering all sessions, CRS increased and VR and VD/VT HB only slightly increased.