• Yi Xin, Kevin Martin, MoraisCaio C ACCADepartment of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA., Paolo Delvecchio, Sarah E Gerard, Hooman Hamedani, Jacob Herrmann, Nicholas Abate, Austin Lenart, Shiraz Humayun, Uday Sidhu, Mihail Petrov, Kristan Reutlinger, Tal Mandelbaum, Ian Duncan, Nicholas Tustison, Stephen Kadlecek, Shampa Chatterjee, James C Gee, Rahim R Rizi, Lorenzo Berra, and Maurizio Cereda.
• Department of Radiology, University of Pennsylvania, Philadelphia, PA.
• Crit. Care Med. 2021 Oct 1; 49 (10): e1015e1024e1015-e1024.

ObjectivesIt is not known how lung injury progression during mechanical ventilation modifies pulmonary responses to prone positioning. We compared the effects of prone positioning on regional lung aeration in late versus early stages of lung injury.DesignProspective, longitudinal imaging study.SettingResearch imaging facility at The University of Pennsylvania (Philadelphia, PA) and Medical and Surgical ICUs at Massachusetts General Hospital (Boston, MA).SubjectsAnesthetized swine and patients with acute respiratory distress syndrome (acute respiratory distress syndrome).InterventionsLung injury was induced by bronchial hydrochloric acid (3.5 mL/kg) in 10 ventilated Yorkshire pigs and worsened by supine nonprotective ventilation for 24 hours. Whole-lung CT was performed 2 hours after hydrochloric acid (Day 1) in both prone and supine positions and repeated at 24 hours (Day 2). Prone and supine images were registered (superimposed) in pairs to measure the effects of positioning on the aeration of each tissue unit. Two patients with early acute respiratory distress syndrome were compared with two patients with late acute respiratory distress syndrome, using electrical impedance tomography to measure the effects of body position on regional lung mechanics.Measurements And Main ResultsGas exchange and respiratory mechanics worsened over 24 hours, indicating lung injury progression. On Day 1, prone positioning reinflated 18.9% ± 5.2% of lung mass in the posterior lung regions. On Day 2, position-associated dorsal reinflation was reduced to 7.3% ± 1.5% (p < 0.05 vs Day 1). Prone positioning decreased aeration in the anterior lungs on both days. Although prone positioning improved posterior lung compliance in the early acute respiratory distress syndrome patients, it had no effect in late acute respiratory distress syndrome subjects.ConclusionsThe effects of prone positioning on lung aeration may depend on the stage of lung injury and duration of prior ventilation; this may limit the clinical efficacy of this treatment if applied late.Copyright © 2021 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.

19 keywords...

hide…