PP group (n=78) Non-PP group (n=78)
P value
Male (%) 62 (79.5) 61 (78.2) 1.000
Age (year) 77.5 (70.0, 83.0) 76.0 (65.0, 86.0) 0.942
BMI (kg/m2) 25.0 (22.7, 27.4) 22.5 (20.8, 25.4) 0.002
SOFA score 8.0 (6.0, 9.0) 7.50 (6.0, 9.0) 0.858
APACHE Ⅱ 22.0 (16.3, 27.0) 22.0 (18.0, 28.0) 0.865
The main reasons for entering the ICU (%)
Mainly due to COVID-19 infection 35 (44.9) 23 (29.5) 0.076
Chronic disease exacerbation 42 (53.8) 51 (65.4)
Trauma 1 (1.3) 4 (5.1)
Intubated (%) 66 (84.6) 70 (89.7) 0.472
Confirmed COVID-19 (%) 60 (76.9) 66 (84.6) 0.310
Infection with sepsis (%) 4 (5.1) 4 (5.1) 1.000
PEEP (cmH2O)a 8.5 (6.3, 10.0) 5.0 (5.0, 7.0) <0.001
Respiratory Rate (breaths/min)a 16.0 (15.0, 20.0) 15.0 (15.0, 15.0) <0.001
Tidal volume (ml)a 456.5 (392.5, 557.3) 452.0 (409.0, 528.0) 0.541
Peak airway pressure (cmH2O)a 23.0 (18.3, 26.0) 20.0 (16.0, 24.0) 0.007
Cydn (ml/cmH2O)a 32.6 (23.3, 41.2) 31.5 (25.6, 40.7) 0.892
Underlying disease (%)
Pre-existing pulmonary disease 30 (38.5) 27 (34.6) 0.739
Hypertension 47 (60.3) 41 (52.6) 0.419
Diabetes 24 (30.8) 22 (28.2) 0.861
Cardiovascular disease 15 (19.2) 14 (17.9) 1.000
Cerebrovascular disease 15 (19.2) 18 (23.1) 0.695
Malignant tumor 19 (24.4) 10 (12.8) 0.100
Hepatitis 6 (7.7) 6 (7.7) 1.000
Chronic kidney disease 11 (14.1) 12 (15.4) 1.000
Chest CT (%)
Pulmonary plaques or Ground-glass opacity 58 (84.1) 62 (86.1) 0.916
Pulmonary fibrosis 13 (18.8) 19 (26.4) 0.385
Pulmonary consolidation 9 (13.0) 9 (12.5) 1.000
Medication use (%)b
Antibiotic 76 (97.4) 45 (57.7) <0.001
Anti COVID-19 39 (50.0) 21 (26.9) 0.005
Immunoglobulin 35 (44.9) 6 (7.7) <0.001
Dexamethasone 71 (91.0) 58 (74.4) 0.011
Norepinephrine 78 (100.0) 63 (80.8) <0.001
Blood gas indicators
PaO2/FiO2 ratio (mmHg) 125.5 (104.3, 169.0) 212.5 (130.5, 289.5) <0.001
FiO2 (%) 60.0 (45.8, 80.0) 50.0 (40.0, 61.0) 0.003
LAC (mmol/L) 2.1 (1.6, 2.8) 2.3 (1.6, 3.2) 0.433
Inflammation
CRP (mg/L) 65.6 (18.4, 129.5) 64.1 (27.5, 133.9) 0.414
PCT (ng/ml) 0.4 (0.1, 2.7) 1.1 (0.4, 3.1) 0.036
Blood system
D-D (mg/L) 2.6 (1.4, 7.4) 2.5 (1.6, 8.3) 0.889
WBC (×109/L) 10.1 (7.8, 12.9) 8.9 (6.4, 13.6) 0.562
LYM (×109/L) 0.5 (0.3, 0.7) 0.5 (0.3, 1.0) 0.328
Hb (g/L) 122.0 (105.3, 138.5) 116.5 (90.3, 130.3) 0.034
PLT (109/L) 162.5 (110.8, 199.8) 156.0 (106.5, 216.0) 0.728
Cardiac function
BNP (pg/ml) 1537.0 (768.3, 3479.5) 1672.0 (472.5, 5370.5) 0.928
TnT (ng/ml) 0.04 (0.02, 0.10) 0.05 (0.03, 0.12) 0.103
LDH (U/L) 516.0 (418.3, 657.0) 386.0 (276.0, 610.0) 0.014
Liver function
ALT (U/L) 27.0 (16.5, 43.5) 25.5 (16.0, 38.8) 0.725
AST (U/L) 39.0 (27.5, 59.5) 44.0 (27.0, 69.0) 0.508
TBIL (μmol/L) 11.0 (7.3, 17.0) 12.1 (8.5, 14.9) 0.523
Renal function
Cr (μmol/L) 97.5 (72.3, 201.5) 112.0 (70.5, 186.3) 0.989
Urea (mmol/L) 11.7 (8.0, 19.4) 12.2 (7.9, 18.0) 0.844
eGFR [ml/(min×1.73m2)] 60.6 (26.9, 81.9) 50.1 (27.0, 86.3) 0.976