1. Mechanisms of oxygenation responses to proning and recruitment in COVID-19 pneumonia
- Author
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Luigi Camporota, Mattia Busana, Stefano Lazzari, Sandra Rossi, Laura Malchiodi, Maria Michela Palumbo, Matteo Bonifazi, Paola Palermo, Simone Gattarello, Federica Romitti, Luciano Gattinoni, John J. Marini, Massimo Cressoni, Peter Herrmann, Irene Steinberg, Leif Saager, Patrizia Ceccarelli, Paolo Bresciani, Emanuele Sani, Konrad Meissner, Michael Quintel, Nicola Sverzellati, and Francesca Collino
- Subjects
medicine.medical_specialty ,ARDS ,Supine position ,medicine.medical_treatment ,Lung recruitment ,Atelectasis ,Critical Care and Intensive Care Medicine ,Mechanical ventilation ,Internal medicine ,Correspondence ,Prone Position ,medicine ,Humans ,Prospective Studies ,Lung ,Respiratory Distress Syndrome ,Pulmonary Gas Exchange ,SARS-CoV-2 ,business.industry ,COVID-19 ,Oxygenation ,respiratory system ,medicine.disease ,respiratory tract diseases ,Prone position ,medicine.anatomical_structure ,Cardiology ,business ,Perfusion - Abstract
This study aimed at investigating the mechanisms underlying the oxygenation response to proning and recruitment maneuvers in coronavirus disease 2019 (COVID-19) pneumonia. Twenty-five patients with COVID-19 pneumonia, at variable times since admission (from 1 to 3 weeks), underwent computed tomography (CT) lung scans, gas-exchange and lung-mechanics measurement in supine and prone positions at 5 cmH2O and during recruiting maneuver (supine, 35 cmH2O). Within the non-aerated tissue, we differentiated the atelectatic and consolidated tissue (recruitable and non-recruitable at 35 cmH2O of airway pressure). Positive/negative response to proning/recruitment was defined as increase/decrease of PaO2/FiO2. Apparent perfusion ratio was computed as venous admixture/non aerated tissue fraction. The average values of venous admixture and PaO2/FiO2 ratio were similar in supine-5 and prone-5. However, the PaO2/FiO2 changes (increasing in 65% of the patients and decreasing in 35%, from supine to prone) correlated with the balance between resolution of dorsal atelectasis and formation of ventral atelectasis (p = 0.002). Dorsal consolidated tissue determined this balance, being inversely related with dorsal recruitment (p = 0.012). From supine-5 to supine-35, the apparent perfusion ratio increased from 1.38 ± 0.71 to 2.15 ± 1.15 (p = 0.004) while PaO2/FiO2 ratio increased in 52% and decreased in 48% of patients. Non-responders had consolidated tissue fraction of 0.27 ± 0.1 vs. 0.18 ± 0.1 in the responding cohort (p = 0.04). Consolidated tissue, PaCO2 and respiratory system elastance were higher in patients assessed late (all p
- Published
- 2021
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