Table 1.
Demographical and clinical conditions of the patients before preoxygenation
| Parameters | Cohorts | Comparisons between cohorts | |
|---|---|---|---|
| NIV | HCO | ||
| Procedure for oxygenation and ventilation | Non-invasive ventilation | High-flow nasal cannula oxygen | |
| Patients included in the analysis | 154 | 161 | p-value |
| Age (years) | |||
| Minimum | 28 | 27 | 0.377 |
| Maximum | 68 | 67 | |
| Mean ± SD | 57.12 ± 11.14 | 58.22 ± 10.91 | |
| Sex | |||
| Male | 105 (68) | 107 (66) | 0.811 |
| Female | 49 (32) | 54 (34) | |
| Body-mass index (kg/m2) | 25.52 ± 1.11 | 25.22 ± 1.85 | 0.084 |
| Simplified Acute Physiology Score II | 53 ± 13 | 50 ± 15 | 0.059 |
| Sepsis-related Organ Failure Assessment score | 8.12 ± 4.35 | 9.01 ± 4.61 | 0.079 |
| Underlying chronic lung disease | 42 (27) | 51 (32) | 0.459 |
| Upper airway tract cancer history | 6 (4) | 4 (2) | 0.531 |
| Reason for the intensive care unit admission | |||
| Respiratory infection | 54 (35) | 61 (38) | 0.392 |
| Chronic obstructive pulmonary disease exacerbation | 10 (7) | 11 (7) | |
| Extra-pulmonary acute respiratory distress syndrome. | 15 (10) | 12 (7) | |
| Pulmonary atelectasis | 5 (3) | 3 (2) | |
| Shock | 42 (27) | 57 (35) | |
| Cardiogenic pulmonary edema | 15 (10) | 8 (5) | |
| Neurologic conditions | 13 (8) | 9 (6) | |
| Vasopressor support at inclusion | 28 (18) | 31 (19) | 0.885 |
| Bilateral pulmonary infiltrates | 77 (50) | 82 (51) | 0.911 |
| Respiratory rates (breaths/ min) | 61 ± 9 | 62 ± 8 | 0.298 |
| The partial pressure of arterial oxygen to fraction of inspired oxygen ratio | |||
| Mild hypoxemia (201–300 mmHg) | 34 (22) | 35 (22) | 0.889 |
| Moderate-to-severe hypoxemia (≤200 mmHg) | 120 (78) | 126 (78) | |
Constant variables are reported as frequency (percentages) and continuous and ordinal variables are reported as mean ± standard deviation (SD)
For constant variables the Fischer exact test and for continuous and ordinal variables the Mann-Whitney U-test was performed for statistical analysis
A p-value of less than 0.05 was considered significant
Fraction of inspired oxygen = 0.21 + oxygen flow rate × 0.03