ORIGINAL ARTICLE   Free access

Minerva Anestesiologica 2020 October;86(10):1057-64

DOI: 10.23736/S0375-9393.20.14130-0

Copyright © 2020 EDIZIONI MINERVA MEDICA

language: English

Dynamic bedside assessment of the physiologic effects of prone position in acute respiratory distress syndrome patients by electrical impedance tomography

Francesca DALLA CORTE ¹, Tommaso MAURI ^{2, 3}, Elena SPINELLI ², Marta LAZZERI ¹, Cecilia TURRINI ¹, Marco ALBANESE ¹, Chiara ABBRUZZESE ², Alfredo LISSONI ², Alessandro GALAZZI ², Nilde ERONIA ⁴, Alfio BRONCO ⁴, Elisabetta MAFFEZZINI ⁴, Antonio PESENTI ^{2, 3}, Giuseppe FOTI ^{4, 5}, Giacomo BELLANI ^{4, 5}, Giacomo GRASSELLI ^{2, 3} ✉

¹ Section of Anesthesia and Intensive Care, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy; ² Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca’ Granda Maggiore Polyclinic Hospital, Milan, Italy; ³ Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; ⁴ Department of Emergency, San Gerardo Hospital, Monza, Italy; ⁵ Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy

BACKGROUND: Prone position (PP) improves acute respiratory distress syndrome (ARDS) survival by reducing the risk of ventilation-induced lung injury. However, inter-individual variability is a hallmark of ARDS and lung protection by PP might not be optimal in all patients. In the present study, we dynamically assessed physiologic effects of PP by electrical impedance tomography (EIT) and identified predictors of improved lung protection by PP in ARDS patients.
METHODS: Prospective physiologic study on 16 intubated, sedated and paralyzed patients with ARDS undergoing PP as per clinical decision. EIT data were recorded during two consecutive steps: 1) baseline supine position before and after a recruitment maneuver (RM); 2) prone position before and after a RM. “Improved lung protection” by PP was defined in the presence of simultaneous improvement of ventilation homogeneity (Hom), alveolar overdistension and collapse (ODCL) and amount of recruitable lung volume by RM in comparison to supine.
RESULTS: PP versus supine increased the tidal volume distending the dependent regions (Vtdep), resulting in improved Hom (1.1±0.9 vs. 1.7±0.9, P=0.021). PP also reduced ODCL (19±9% vs. 28±8%, P=0.005) and increased the recruitable lung volume (80 [71-157] vs. 59 [1-110] mL, P=0.025). “Improved lung protection” by PP was predicted by lower Vtdep, higher Vtndep and poorer Hom measured during baseline supine position (P<0.05).
CONCLUSIONS: EIT enables dynamic bedside assessment of the physiologic effects of PP and might support early recognition of ARDS patients more likely to benefit from PP.

KEY WORDS: Electrical impedance; Prone position; Adult respiratory distress syndrome; Respiratory insufficiency; Ventilator-induced lung injury