Mechanical Ventilation Strategies Targeting Different Magnitudes of Collapse and Tidal Recruitment in Porcine Acid Aspiration-Induced Lung Injury

• Published in: Journal of clinical medicine Vol. 8; no. 8; p. 1250
• Main Authors: Haase, Juliane, Buchloh, Dorina C, Hammermüller, Sören, Salz, Peter, Mrongowius, Julia, Carvalho, Nadja C, Beda, Alessandro, Rau, Anna, Starke, Henning, Spieth, Peter M, Gittel, Claudia, Muders, Thomas, Wrigge, Hermann, Reske, Andreas W
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 18.08.2019
• Subjects: acute respiratory distress syndrome; lung protective mechanical ventilation; positive end-expiratory pressure; lung recruitment; electrical impedance tomography
• ISSN: 2077-0383; 2077-0383
• DOI: 10.3390/jcm8081250

Reducing ventilator-associated lung injury by individualized mechanical ventilation (MV) in patients with Acute Respiratory Distress Syndrome (ARDS) remains a matter of research. We randomly assigned 27 pigs with acid aspiration-induced ARDS to three different MV protocols for 24 h, targeting different magnitudes of collapse and tidal recruitment (collapse&TR): the ARDS-network (ARDSnet) group with low positive end-expiratory pressure (PEEP) protocol (permissive collapse&TR); the Open Lung Concept (OLC) group, PaO /FiO >400 mmHg, indicating collapse&TR <10%; and the minimized collapse&TR monitored by Electrical Impedance Tomography (EIT) group, standard deviation of regional ventilation delay, SD . We analyzed cardiorespiratory parameters, computed tomography (CT), EIT, and post-mortem histology. Mean PEEP over post-randomization measurements was significantly lower in the ARDSnet group at 6.8 ± 1.0 cmH O compared to the EIT (21.1 ± 2.6 cmH O) and OLC (18.7 ± 3.2 cmH O) groups (general linear model (GLM) < 0.001). Collapse&TR and SD , averaged over all post-randomization measurements, were significantly lower in the EIT and OLC groups than in the ARDSnet group (collapse < 0.001, TR = 0.006, SD < 0.004). Global histological diffuse alveolar damage (DAD) scores in the ARDSnet group (10.1 ± 4.3) exceeded those in the EIT (8.4 ± 3.7) and OLC groups (6.3 ± 3.3) ( = 0.16). Sub-scores for edema and inflammation differed significantly (ANOVA < 0.05). In a clinically realistic model of early ARDS with recruitable and nonrecruitable collapse, mechanical ventilation involving recruitment and high-PEEP reduced collapse&TR and resulted in improved hemodynamic and physiological conditions with a tendency to reduced histologic lung damage.