Proning reduces ventilation heterogeneity in patients with elevated BMI: implications for COVID-19 pneumonia management?

Abstract

Simulations of patient-based lungs suggest that proning reduces ventilation heterogeneity in overweight and obese subjects but increases heterogeneity in non-overweight subjects. This suggests proning may be beneficial for overweight #COVID19 patients. https://bit.ly/2MfCiyk.

FIGURE 1

Comparative ventilation heterogeneity between supine and prone positions, stratified by body mass index (BMI). a) Ventilation improvement (percentage reduction in alveolar volume variance at peak inhalation) when moved from supine to prone is given for 31 patient-based lung structures, with b) a clear and statistically significant (*) ventilation improvement in obese compared with non-obese patients. c) Average inspiratory lung volume for 10 slices (from dorsal to ventral), with standard deviation of volumes, for high- and low-BMI patients. d) Ventilation maps in supine and prone positions in two patients. Brighter colours indicate increased ventilation. When moving from supine to prone, the low-BMI patient experiences a significant reversal in volume distribution, while the high-BMI patient experiences a flattening out of the volume distribution, suggesting reduced ventilation heterogeneity. Ventilation maps were created by calculating the average ventilation ratio per voxel, in an 80-80-80 grid overlaid on each structure. Each image is the average of 10 central voxels in the vertical axis.