TABLE 1.
Patient characteristics on ICU admission, clinical course, and outcomes
| Characteristics | All patients (N = 42) | HFNC success (n = 22) | HFNC failure (n = 20) | P value a |
|---|---|---|---|---|
| Baseline | ||||
| Age, median [IQR], years | 67 [59‐72.5] | 65 [54‐70] | 69 [64‐75] | 0.03 |
| Male, sex, n (%) | 28 (66) | 15 (68) | 13 (65) | 1 |
| Obesity, BMI≥30 kg/m2, n (%) | 16 (38) | 9 (41) | 7 (35) | 0.76 |
| Sequential organ failure assessment, median [IQR] | 3.5 [3‐5] | 3 [3–4] | 4 [3‐6] | 0.02 |
| White blood cell counts, median [IQR], ×10^9/L | 8.0 [6.8‐9.3] | 9.0 [7.6‐10.7] | 6.9 [6.1‐7.8] | 0.01 |
| Platelet counts, median [IQR], ×10^9/L | 256 [205‐318] | 313 [246‐398] | 199 [163‐238] | 0.002 |
| Chest computed tomography b Percentage of lung damage, median [IQR] (%) |
52.5 [50‐63.75] |
55 [50‐60] |
50.0 [50.0‐67.5] |
0.51 |
| Respiratory measures of patients at ICU admission, median [IQR] | ||||
| Respiratory rate, per min | 24 [19.5‐28.5] | 23 [18‐27] | 25 [21‐30] | 0.09 |
| Ratio PaO2/FiO2 | 125.5 [96‐161] | 128 [100‐176] | 121.5 [88.5135.5] | 0.16 |
| FiO2 HFNC, % | 66 [59‐80] | 65 [60‐80] | 67.5 [57.5‐80] | 0.60 |
| Flow HFNC, L/min | 57.5 [59–80] | 60 [50‐60] | 55 [50‐60] | 0.80 |
| Respiratory measures of patients at Nadir, median [IQR] | ||||
| Respiratory rate, per min | 32 [28‐37] | 31 [28‐35]] | 33.5 [28‐39] | 0.53 |
| Ratio PaO2/FiO2 | 99.5 [78.5‐112] | 110 [87.5‐127.5] | 89 [69.5‐96] | 0.01 |
| FiO2, (%) | 86 [80‐100] | 72.5 [60‐100] | 100 [100‐100] | 0.003 |
| Flow HFNC, L/min | 60 [60‐60] | 60 [60‐60] | 60 [60‐60] | 1 |
| Prediction of HFNC success by ROX index c | ||||
| ROX index at H2, median [IQR] d | 6,23 [5,13‐7,63] | 6,33 [4,98‐8,30] | 6,12 [5,29‐6,91] | 0,64 |
| ROX index at H6, median [IQR] | 6,78 [4,89‐8,56] | 7,03 [5,20‐9,37] | 6,52 [4,57‐7,75] | 0,18 |
| ROX index at H12, median [IQR] | 6.19 [5.20‐7.89] | 6.82 [5.80‐9.12] | 5.56 [4.60‐6.67] | 0.04 |
| ROX index >4.88 at H12, n (%) e | 28 (78) | 20 (91) | 8 (57) | 0.04 |
| ICU clinical course | ||||
| Time from ICU admission to intubation, median [IQR] hours | ‐ | ‐ | 24 [10–49] | ‐ |
| Use of vasopressors f | 20 (48) | 0 (0) | 20 (100) | 0.0003 |
| Acute kidney injury g | 17 (40) | 4 (18) | 13 (65) | 0.004 |
| Acute liver injury h | 7 (17) | 1 (4) | 6 (30) | 0.04 |
| Ventilator‐associated pneumonia i | ‐ | ‐ | 7 (35) | ‐ |
| Outcomes | ||||
| Median length of stay in ICU survivors, median [IQR] days | 8 [5‐19] | 7 [4‐8] | 23 [18‐42] | 0.0001 |
| Died at day 28, n (%) | 6 (13) | 0 (0) | 6 (30) | 0.007 |
| Discharged from hospital at day 28, n (%) | 17 (40) | 16 (73) | 1 (0.5) | 0.00001 |
Abbreviations: BMI, body mass index; FiO2, fraction of inspired oxygen; ICU, intensive care unit; IQR, interquartile; HFNC, high‐flow nasal cannula; PaO2, partial pressure of oxygen.
Nonparametric tests or Fischer exact test comparing HFNC success vs HFNC failure, as appropriate.
Data available for 29/42 patients.
The ROX index was defined as the ratio of SpO2/FIO2(%) to RR (breaths/min). The ROX index is an early marker to predicting the success or failure of HFNC.
Measures performed on 39 patients.
Measures performed on 36 patients.
Use of vasopressors defined as norepinephrine intravenous administration (more than 0.2 μg/kg/min).
Acute kidney injury stages 2 and 3 according to the 2012 Kidney Disease: Improving Global Outcomes (KDIGO).
Defined as alanine aminotransferase or aspartate aminotransferase level greater than three times the upper limit of normal.
Definition according to IDSA/ATS criteria.