Table 1.
Patient demographic and clinical characteristics
| Variable | Intubated patients (n = 113) | Non-intubated patients (n = 201) | p value |
|---|---|---|---|
| Sex, male, n (%) | 68 (60.2) | 101 (50.2) | 0.091 |
| Age (years), median [IQR] | 77 [67, 83] | 73 [65, 85] | 0.603 |
| BMI (kg/m2), mean ± SD | 22.7 ± 5.5 | 22.9 ± 5.8 | 0.678 |
| Charlson Comorbidity Index, median [IQR] | 3 [1, 5] | 3 [1, 5] | 0.968 |
| Comorbidities, n (%) | |||
| COPD | 22 (19.5) | 42 (20.9) | 0.764 |
| Chronic renal disease stage 4 or 5 | 13 (11.5) | 37 (18.4) | 0.127 |
| History of myocardial infarction | 31 (27.4) | 47 (23.4) | 0.426 |
| Heart failure | 32 (28.3) | 71 (35.3) | 0.205 |
| History of a cerebrovascular event | 32 (28.3) | 54 (26.9) | 0.782 |
| Dementia | 18 (15.9) | 24 (11.9) | 0.320 |
| Post-COVID-19 status | 18 (15.9) | 25 (12.4) | 0.388 |
| Vital signs | |||
| SBP, mmHg, mean ± SD | 126 ± 35 | 132 ± 34 | 0.137 |
| MAP, mmHg, mean ± SD | 88 ± 23 | 92 ± 22 | 0.072 |
| Hypotension (SBP ≤ 90 or MAP ≤ 65 mmHg), n (%) | 15 (13.3) | 24 (11.9) | 0.731 |
| Heart rate, bpm, mean ± SD | 102 ± 23 | 98 ± 23 | 0.216 |
| Respiratory rate, per minute, median [IQR] | 28 [24, 32] | 26 [24, 30] | 0.014 |
| Respiratory rate > 30 per minute, n (%) | 33 (29.2) | 42 (20.1) | 0.098 |
| SpO2, (%), median [IQR] | 94 [90, 98] | 96 [92, 99] | 0.006 |
| Glasgow Coma Scale score, median [IQR] | 15 [13, 15] | 15 [15] | < 0.001 |
| Glasgow Coma Scale score < 15, n (%) | 41 (36.3) | 33 (16.4) | 0.002 |
| Blood gas analysis | |||
| pH, mean ± SD | 7.37 ± 0.11 | 7.41 ± 0.08 | 0.001 |
| PaO2, mmHg, median [IQR] | 125 [84, 18] | 130 [82, 172] | 0.362 |
| PaCO2, mmHg, median [IQR] | 33 [27, 42] | 33 [29, 40] | 0.910 |
| PF ratio, mean ± SD | 377.77 ± 137.47 | 391.87 ± 135.20 | 0.379 |
| Bicarbonate, mEq/L, mean ± SD | 19.9 ± 6.1 | 21.6 ± 4.8 | 0.007 |
| Blood lactate, mmol/L, median [IQR] | 1.7 [0.8, 3.3] | 1.8 [1.0, 2.8] | 0.717 |
| Serum creatinine, mg/dL, median [IQR] | 1.18 [0.79, 1.72] | 1.14 [0.82, 1.82] | 0.848 |
| SOFA score, median [IQR] | 3 [2, 5] | 2 [1, 4] | 0.001 |
| Non-invasive respiratory support, n (%) | 88 (77.9) | 131 (65.2) | 0.019 |
| Final diagnosis, n (%) | |||
| Respiratory infection | 63 (55.8) | 73 (36.3) | 0.001 |
| Sepsis | 76 (67.3) | 73 (36.3) | < 0.001 |
| Acute exacerbation of COPD | 20 (17.7) | 37 (18.4) | 0.876 |
| Asthma attack | 4 (3.5) | 10 (5.0) | 0.555 |
| Cardiogenic pulmonary edema | 22 (19.5) | 61 (30.3) | 0.036 |
| COVID-19 pneumonia | 17 (15.0) | 7 (3.5) | 0.050 |
| Diaphragmatic excursion, cm, median [IQR] | 0.9 [0.76, 1.10] | 1.8 [1.30, 2.40] | < 0.001 |
BMI body mass index, COPD chronic obstructive pulmonary disease, COVID-19 coronavirus disease 2019, IQR interquartile range, PaO2 partial pressure of arterial oxygen, PaCO2 partial pressure of arterial carbon dioxide, PF ratio ratio of the partial pressure of arterial oxygen to inspired oxygen fraction, SD standard deviation, SOFA Sequential Organ Failure Assessment, SpO2 blood oxygen saturation level