Individual values of baseline Δ
PP according to volume responsiveness status and to either respiratory change in PAOP (ΔPAOP) or airway driving pressure. For the purpose of this physiological analysis, patients with ultrasonographic signs of acute cor pulmonale were excluded. The central boxes represent the values from the lower to the upper quartile (25th to 75th percentile). The middle line represents the median. ΔRESPPP, respiratory changes in pulse pressure to predict a 10% increase in cardiac output after 500-ml volume expansion; AUC, area under the receiver-operating characteristic curve. (A) Analysis of the 33 patients with a pulmonary artery catheter. Median for respiratory changes in pulmonary artery occlusion pressure (PAOP) was 4 mmHg. Respiratory change in PAOP equals tidal volume (Vt) divided by chest wall compliance (see Additional file 1 for detailed calculations). Therefore, patients represented in the right part of the figure are those combining a higher Vt and lower chest wall compliance. (B) The median airway driving pressure was 10 cmH2O (n = 59).