Murgolo Francesco, Grieco Domenico L, Spadaro Savino, Bartolomeo Nicola, di Mussi Rossella, Pisani Luigi, Fiorentino Marco, Crovace Alberto Maria, Lacitignola Luca, Staffieri Francesco, Grasso Salvatore
Department of Precision-Regenerative Medicine and Jonic Area (DiMePRe-J), Section of Anesthesiology and Intensive Care Medicine, University of Bari "Aldo Moro", Bari, Italy.
Dipartimento di Medicina di Precisione e Rigenerativa e Area Jonica (DiMePRe-J), Sezione di Anestesiologia e Rianimazione, Ospedale Policlinico, Università Degli Studi "Aldo Moro", Piazza Giulio Cesare 11, Bari, Italy.
Ann Intensive Care. 2024 Jul 4;14(1):106. doi: 10.1186/s13613-024-01343-w.
The recruitment-to-inflation ratio (R/I) has been recently proposed to bedside assess response to PEEP. The impact of PEEP on ventilator-induced lung injury depends on the extent of dynamic strain reduction. We hypothesized that R/I may reflect the potential for lung recruitment (i.e. recruitability) and, consequently, estimate the impact of PEEP on dynamic lung strain, both assessed through computed tomography scan.
Fourteen lung-damaged pigs (lipopolysaccharide infusion) underwent ventilation at low (5 cmHO) and high PEEP (i.e., PEEP generating a plateau pressure of 28-30 cmHO). R/I was measured through a one-breath derecruitment maneuver from high to low PEEP. PEEP-induced changes in dynamic lung strain, difference in nonaerated lung tissue weight (tissue recruitment) and amount of gas entering previously nonaerated lung units (gas recruitment) were assessed through computed tomography scan. Tissue and gas recruitment were normalized to the weight and gas volume of previously ventilated lung areas at low PEEP (normalized-tissue recruitment and normalized-gas recruitment, respectively).
Between high (median [interquartile range] 20 cmHO [18-21]) and low PEEP, median R/I was 1.08 [0.88-1.82], indicating high lung recruitability. Compared to low PEEP, tissue and gas recruitment at high PEEP were 246 g [182-288] and 385 ml [318-668], respectively. R/I was linearly related to normalized-gas recruitment (r = 0.90; [95% CI 0.71 to 0.97) and normalized-tissue recruitment (r = 0.69; [95% CI 0.25 to 0.89]). Dynamic lung strain was 0.37 [0.29-0.44] at high PEEP and 0.59 [0.46-0.80] at low PEEP (p < 0.001). R/I was significantly related to PEEP-induced reduction in dynamic (r = - 0.93; [95% CI - 0.78 to - 0.98]) and global lung strain (r = - 0.57; [95% CI - 0.05 to - 0.84]). No correlation was found between R/I and and PEEP-induced changes in static lung strain (r = 0.34; [95% CI - 0.23 to 0.74]).
In a highly recruitable ARDS model, R/I reflects the potential for lung recruitment and well estimates the extent of PEEP-induced reduction in dynamic lung strain.
最近有人提出用复张-充气比（R/I）在床旁评估对呼气末正压（PEEP）的反应。PEEP对呼吸机诱导的肺损伤的影响取决于动态应变降低的程度。我们假设R/I可能反映肺复张的潜力（即可复张性），并因此估计PEEP对动态肺应变的影响，两者均通过计算机断层扫描评估。
14只肺损伤猪（输注脂多糖）接受低PEEP（5 cmH₂O）和高PEEP（即产生平台压为28 - 30 cmH₂O的PEEP）通气。通过从高PEEP到低PEEP的单次呼吸去复张操作测量R/I。通过计算机断层扫描评估PEEP诱导的动态肺应变变化、非充气肺组织重量差异（组织复张）和进入先前未充气肺单位的气体量（气体复张）。组织和气体复张分别相对于低PEEP时先前通气肺区域的重量和气体体积进行标准化（分别为标准化组织复张和标准化气体复张）。
在高PEEP（中位数[四分位间距]20 cmH₂O [18 - 21]）和低PEEP之间，中位数R/I为1.08 [0.88 - 1.82]，表明肺复张潜力高。与低PEEP相比，高PEEP时的组织和气体复张分别为246 g [182 - 288]和385 ml [318 - 668]。R/I与标准化气体复张呈线性相关（r = 0.90；[95%置信区间0.71至0.97]）和标准化组织复张（r = 0.69；[95%置信区间0.25至0.89]）。高PEEP时动态肺应变为0.37 [0.29 - 0.44]，低PEEP时为0.59 [0.46 - 0.80]（p < 0.001）。R/I与PEEP诱导的动态（r = - 0.93；[95%置信区间 - 0.78至 - 0.98]）和整体肺应变降低显著相关（r = - 0.57；[95%置信区间 - 0.05至 - 0.84]）。未发现R/I与PEEP诱导的静态肺应变变化之间存在相关性（r = 0.34；[95%置信区间 - 0.23至0.74]）。
在高可复张性的急性呼吸窘迫综合征模型中，R/I反映肺复张潜力，并能很好地估计PEEP诱导的动态肺应变降低程度。
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