Table 3.
Quantitative CT analysis parameters. Data are presented as median [interquartile range]. PEEP: positive end-expiratory pressure; HU: Hounsfield Units; IQR: interquartile range; CI: confidence interval. *Significant p < 0.05.
| Parameter | All (N = 52) | Early intubation (N = 26) | Late intubation (N = 26) | p |
|---|---|---|---|---|
| Scan at PEEP 8 cmH2O | ||||
| Total lung volume, median [IQR], (mL) | 2965 [2517–3810] | 3245 [2734–3811] | 2693 [2338–3419] | 0.219 |
| Total lung weight (g) | 1560 [1292–1973] | 1440 [1146–1880] | 1623 [1436–2019] | 0.168 |
| Excess lung weight (%) | 58 [28–82] | 50 [22–62] | 66 [46–90] | 0.048* |
| Gas volume, median [IQR], (mL) | 1277 [889–2032] | 1603 [1210–2126] | 1086 [744–1646] | 0.029* |
| As proportion of the total lung volume, median [IQR], (%) | 46.7 [33.7–56.1] | 54.3 [43.7–62.8] | 39.5 [32.6–50.5] | 0.006* |
| Mean attenuation, median [IQR], (HU) | -451 [− 561 to − 324] | -543 [− 628 to − 436] | -369 [− 498 to − 316] | 0.005* |
| Hyper-aerated mass, median [IQR], (g) | 12 [5–24] | 16 [9–27] | 8 [5–21] | 0.157 |
| Normally aerated mass, median [IQR], (g) | 350 [245–458] | 388 [322–465] | 320 [203–380] | 0.031* |
| Poorly aerated mass, median [IQR], (g) | 525 [394–688] | 398 [341–633] | 577 [486–694] | 0.014* |
| Non-aerated mass, median [IQR], (g) | 716 [426–841] | 527 [375–811] | 755 [586–876] | 0.049* |
| Changes from PEEP 8 cmH2O to PEEP 16 cmH2O | ||||
| Lung recruitment (changes in non-aerated), median [IQR], (%) | 3.1 [1.4–4.7] | 3.2 [1.4–4.6] | 2.9 [1.5–4.8] | 0.964 |
| Changes in poorly aerated, median [IQR], (%) | 1.4 [0.0–3.1] | 3.1 [0.7–3.6] | 1.1 [− 0.2–1.5] | 0.001* |
| Changes in gas volume, median [IQR], (mL) | 397 [280–484] | 448 [373–609] | 277 [230–397] | < 0.001* |