Targeted Lateral Positioning Decreases Lung Collapse and Overdistension in COVID-19-Associated ARDS

Abstract

Background Among the challenges for personalizing the management of mechanically ventilated patients with coronavirus disease (COVID-19)-associated acute respiratory distress syndrome (ARDS) are the effects of different positive end-expiratory pressure (PEEP) levels and body positions in regional lung mechanics. Right-left lung aeration asymmetry and poorly recruitable lungs with increased recruitability with alternating body position between supine and prone have been reported. However, real-time effects of changing body position and PEEP on regional overdistension and collapse, in individual patients, remain largely unknown and not timely monitored. Methods We here report a series of consecutive mechanically ventilated patients with COVID-19-associated ARDS. Aiming at to individualize PEEP and body positioning in order to reduce mechanisms of ventilator-induced lung injury, collapse and overdistension, sixteen decremental PEEP titrations were performed in the first days of mechanical ventilation (8 pairs supine vs. targeted lateral position): supine position immediately followed by 30° targeted lateral position. The choice of lateral tilt was based on X-Ray: the less aerated lung was positioned up. Maps and percentages of global and regional collapse and overdistension were measured for each PEEP level by electrical impedance tomography. Results Targeted lateral position resulted in significantly smaller amounts of overdistension and collapse when compared with the supine one: less collapse along the PEEP titration was found within the left lung in targeted lateral; and less overdistension along the PEEP titration was found within the right lung in targeted lateral. Regarding collapse within the right lung and overdistension within the left lung: no differences were found for position. Conclusions Targeted lateral positioning with bedside personalized PEEP provided a selective attenuation of overdistension and collapse in mechanically ventilated patients with COVID-19-associated ARDS and right-left lung aeration/ventilation asymmetry.

Prone Positioning May Increase Lung Overdistension in COVID-19-Induced ARDS

“…Our data underpin the importance of timely PEEP titrations tackling the dynamically changing phases of this disease [8]. They put forward the importance of monitoring and quantifying in real-time changes in overdistension and collapse -as well as the relevance of personalized PEEP adjustments -every time body positions are changed [10]. The recommendation of applying nonpersonalized low or high PEEP may lead to insu cient and/or excessive PEEP in terms of protection of VILI [8].…”

“…We used EIT with decremental PEEP titration algorithm (PEEP EIT−titration ) [10], which provides information on regional overdistension and collapse [11], along with global respiratory system compliance, to individualize PEEP and body position aiming to minimize ventilator-induced lung injury (VILI) mechanisms, namely collapse and overdistension. EIT is a noninvasive, radiation-free, real-time imaging method that measures regional changes in lung volumes.…”

Electrical Impedance Tomography in Acute Respiratory Distress Syndrome Management

“…Proper placement of the belt is essential, as caudal placement increases the possibility of measuring diaphragmatic excursion in the frame (116). Similarly, as body positioning (lateral, prone, or the angle inclination of the bed) (56, 117) influences the mechanical properties of the lung (118), it can also modify tidal impedance distribution and variability. Therefore, when an intervention is being assessed (e.g., PEEP titration), the evaluation of impedance changes must be in the same position pre- and postinterventions.…”

Electrical impedance tomography in the adult intensive care unit: clinical applications and future directions

“…One observational study of 5 patients used EIT to successfully demonstrate that titrating PEEP with targeted lateral positioning to keep the less aerated side higher yielded less regional overdistention and collapse and improved right-left lung aeration/ven- tilation asymmetry [41 ▪ ]. Another study of 10 nonintubated patients with COVID ARDS used EIT to measure changes in end-expiratory lung impedance during single PEEP de-escalation (from 12 to 6 mmH 2 O) via continuous positive airway pressure before intubation.…”