Introduction
Methods
Patient inclusion flow and data collection
Protocol for DECT analysis
Lung gas:blood volume matching analysis
Statistical analysis
Results
Population description
All (N = 35) | Non-invasive (N = 12) | Invasive (N = 23) | p | |
---|---|---|---|---|
Age | 59 [55–64] | 58 [55–62] | 60 [53–67] | 0.694 |
Sex (male), n (%) | 30 | 10 | 20 | |
Weight (kg) | 80 [75–96] | 90 [85–96] | 80 [73–95] | 0.173 |
Body mass index (kg/m2) | 28 [25–31] | 28 [28–31] | 28 [24–32] | 0.521 |
Days since onset of symptoms | 19 [16–31] | 18 [16–19] | 25 [15–35] | 0.045* |
Days since first confirmed swab | 16 [9–22] | 12 [9–14] | 20 [11–32] | 0.026* |
Days since hospital admission | 13 [7–21] | 12 [8–13] | 19 [7–31] | 0.115 |
Days since ICU admission | 12 [3–21] | 12 [8–13] | 15 [2–31] | 0.161 |
Comorbidities | ||||
Charlson Comorbidity Index | 1 [1, 2] | 2 [1, 2] | 1 [1, 2] | 0.878 |
Hypertension, n (%) | 14 (40.0) | 6 (50.0) | 8 (34.8) | 0.477 |
Diabetes, n (%) | 6 (17.1) | 2 (16.7) | 4 (17.4) | > 0.999 |
History of pulmonary embolism, n (%) | 1 (2.9) | 0 (0.0) | 1 (4.3) | > 0.999 |
Chronic obstructive lung disease, n (%) | 3 (8.6) | 2 (16.7) | 1 (4.3) | 0.266 |
Chronic therapy | ||||
Calcium channel blockers, n (%) | 2 (5.7) | 1 (8.3) | 1 (4.3) | > 0.999 |
Angiotensin II receptor blockers, n (%) | 4 (11.4) | 3 (25.0) | 1 (4.3) | > 0.999 |
Angiotensin-converting enzyme inhibitors, n (%) | 3 (8.6) | 2 (16.7) | 1 (4.3) | 0.239 |
Oral anticoagulants, n (%) | 2 (5.7) | 2 (16.7) | 0 (0.0) | 0.098 |
Antiplatelet therapy, n (%) | 5 (14.3) | 5 (41.7) | 0 (0.0) | 0.150 |
Steroids in the previous month, n (%) | 3 (8.6) | 2 (16.7) | 1 (4.3) | 0.239 |
Drugs received during ICU stay | ||||
Darunavir/ritonavir, n (%) | 5 (14.3) | 0 (0.0) | 5 (21.7) | 0.150 |
Hydroxychloroquine, n (%) | 24 (68.6) | 10 (83.3) | 14 (60.9) | 0.432 |
Remdesivir, n (%) | 1 (2.9) | 0 (0.0) | 1 (4.3) | > 0.999 |
Tocilizumab, n (%) | 12 (34.3) | 5 (41.7) | 7 (30.4) | 0.709 |
Methylprednisolone, n (%) | 15 (42.9) | 6 (50.0) | 9 (39.1) | 0.721 |
Anticoagulation regimen | ||||
None, n (%) | 1 (2.9) | 0 (0.0) | 1 (4.3) | 0.098 |
Enoxaparin, prophylactic dose, n (%) | 9 (25.7) | 6 (50.0) | 3 (13.0) | |
Enoxaparin, therapeutic dose, n (%) | 18 (51.4) | 5 (41.7) | 13 (56.5) | |
Sodium heparin (continuous infusion), n (%) | 7 (20.0) | 1 (8.3) | 6 (26.1) | |
Blood analyses | ||||
Interleukin-6 (ng/L) | 45 [8–153] | 18 [8–45] | 85 [10–739] | 0.115 |
D-dimer (mcg/L) | 1497 [990–4126] | 1024 [519–2792] | 1581 [1174–5358] | 0.023* |
Ferritin (mcg/L) | 921 [603–1888] | 733 [477–904] | 1399 [888–1929] | 0.016* |
C-reactive protein (mg/L) | 17 [9–89] | 10 [5–16] | 40 [13–107] | 0.017* |
Gas exchange | ||||
pHa | 7.43 [7.40–7.45] | 7.44 [7.42–7.47] | 7.43 [7.34–7.45] | 0.184 |
PaCO2 (mmHg) | 43 [39–53] | 39 [37–42] | 47 [42–55] | 0.001* |
PaO2 (mmHg) | 94 [77–125] | 108 [93–144] | 82 [71–97] | 0.023* |
PaO2/FiO2 (mmHg) | 179 [117–195] | 194 [186–250] | 139 [108–188] | 0.002* |
Bicarbonate (mEq/L) | 28 [25–31] | 27 [25–28] | 29 [25–33] | 0.071 |
Respiratory parameters | ||||
PEEP (cmH2O) | 10 [8–10] | 10 [8–10] | 10 [8–12] | 0.959 |
FiO2 (%) | 60 [50–70] | 60 [45–63] | 60 [50–70] | 0.172 |
Respiratory rate (min−1) | 19 [16–24] | 16 [14–20] | 20 [16–25] | 0.011* |
Tidal volume per predicted body weight (mL/kg) | 7.3 [5.5–7.8] | n.a | 7.3 [5.5–7.8] | n.a |
Driving pressure (cmH2O) | 16 [12–18] | n.a | 16 [12–18] | n.a |
Plateau pressure (cmH2O) | 25 [21–28] | n.a | 25 [21–28] | n.a |
Compliance (mL/cmH2O) | 34 [22–43] | n.a | 34 [22–43] | n.a |
Ventilatory ratio | 1.8 [1.4–2.4] | n.a | 1.8 [1.4–2.4] | n.a |
Parameter | All (N = 35) | Non-invasive (N = 12) | Invasive (N = 23) | p |
---|---|---|---|---|
Lung volume (mL) | 2794 [2150 to 3690] | 3680 [3180 to 4245] | 2359 [1934 to 3207] | 0.001 |
Mean attenuation (HU) | − 615 [− 687 to − 454] | − 771 [− 807 to − 649] | − 506 [− 639 to − 406] | < 0.001* |
Lung weight§ (g) | 1039 [878 to 1268] | 966 [759 to 1061] | 1086 [884 to 1283] | 0.045* |
Pulmonary gas volume (mL) (Vgas) | 1621 [1019 to 2498] | 2929 [1873 to 3350] | 1140 [726 to 1765] | < 0.001* |
Evidence of macroscopic pulmonary embolism, n (%) | 6 (17.1) | 1 (8.0) | 5 (21.7) | 0.640 |
Non-perfused tissue (g) | 138 [90 to 219] | 118 [87 to 201] | 180 [102 to 262] | 0.327 |
Dead-space tissue (g) | 87 [57 to 162] | 87 [71 to 142] | 86 [51 to 171] | 0.503 |
Non-aerated/non-perfused lung tissue (g) | 33 [12 to 84] | 11 [3 to 21] | 65 [29 to 105] | 0.001* |
Shunt tissue (g) | 193 [70 to 299] | 39 [20 to 128] | 253 [180 to 357] | < 0.001* |
Tissue with gas:blood volume ratio < 1 (g) | 360 [292 to 435] | 429 [325 to 464] | 355 [291 to 423] | 0.195 |
Tissue with gas:blood volume ratio > 1 (g) | 293 [249 to 355] | 295 [273 to 328] | 293 [248 to 365] | 0.932 |
Lung DECT analysis—pulmonary gas volume distribution
Lung DECT analysis—pulmonary blood volume distribution
Lung DECT analysis—gas:blood volume matching
Correlations between clinical and DECT parameters
Dual-energy computed tomography parameters | D-dimer C-reactive protein | Respiratory system compliance§ | PaO2/FiO2 | PaCO2 | Ventilatory Ratio§ | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
ρ | p | ρ | p | ρ | p | ρ | p | ρ | p | ρ | p | |
Normally aerated lung tissue (%) | − 0.403 | 0.016* | − 0.488 | 0.003* | 0.284 | 0.189 | 0.730 | < 0.001* | 0.483 | 0.003* | − 0.351 | 0.101 |
Poorly aerated lung tissue (%) | 0.343 | 0.044* | 0.236 | 0.172 | − 0.144 | 0.511 | − 0.342 | 0.044* | − 0.221 | 0.201 | 0.407 | 0.054 |
Non-aerated lung tissue (%) | 0.379 | 0.025* | 0.575 | < 0.001* | − 0.280 | 0.196 | − 0.637 | < 0.001* | − 0.383 | 0.023* | 0.108 | 0.625 |
Non-perfused lung tissue (%) | 0.418 | 0.012* | 0.061 | 0.730 | − 0.071 | 0.747 | − 0.12 | 0.491 | 0.385 | 0.023* | 0.432 | 0.040* |
Shunt lung tissue (%) | 0.186 | 0.285 | 0.486 | 0.003* | − 0.105 | 0.634 | − 0.579 | < 0.001* | 0.261 | 0.130 | − 0.149 | 0.497 |
Lung tissue with gas:blood volume ratio < 1 (%) | − 0.418 | 0.012* | − 0.557 | 0.001* | 0.422 | 0.045* | 0.481 | 0.003* | − 0.441 | 0.008* | 0.067 | 0.761 |
Lung tissue with gas:blood volume ratio > 1 (%) | − 0.285 | 0.097 | − 0.169 | 0.333 | − 0.166 | 0.449 | 0.471 | 0.004* | − 0.227 | 0.190 | − 0.116 | 0.599 |
Dead-space lung tissue (%) | 0.101 | 0.565 | − 0.351 | 0.039* | 0.165 | 0.451 | 0.289 | 0.092 | 0.070 | 0.690 | 0.205 | 0.349 |
Non-aerated, non-perfused lung tissue (%) | 0.513 | 0.002* | 0.531 | 0.001* | − 0.212 | 0.332 | − 0.439 | 0.008* | 0.497 | 0.002* | 0.368 | 0.084 |
Lung tissue with gas:blood volume mismatch (%) | 0.440 | 0.008* | 0.481 | 0.003* | − 0.138 | 0.529 | − 0.633 | < 0.001* | 0.440 | 0.008* | 0.163 | 0.457 |