Table 2. Parameters of patients with hypoxemic respiratory failure at various stages of HFNC use.
| Parameters | Patients with pneumonia only (n = 263) | Patients with non-pneumonia conditions only (n = 220) | ||||
|---|---|---|---|---|---|---|
| Patients who failed HFNC and required intubation (n = 101) | Patients who used HFNC successfully and avoided intubation (n = 162) | p value | Patients who failed HFNC and required intubation (n = 84) | Patients who used HFNC successfully and avoided intubation (n = 136) | p value | |
| Clinical and serological parameters (Median, Inter-quartile range) | ||||||
| Immediately prior to HFNC initiation | ||||||
| Pre-HFNC BIPAP use (%) | 18 (17.8) | 33 (20.5) | 0.634 | 20 (23.8) | 41 (30.2) | 0.354 |
| Pre-HFNC CPAP use (%) | 11 (10.9) | 26 (16.2) | 0.277 | 13 (15.5) | 23 (16.9) | 0.853 |
| Respiratory rate (breaths/min) | 27 (23–33) | 24 (20–28) | 0.006* | 25 (21–29) | 24 (19–29) | 0.417 |
| FiO2 (%) | 50 (40–100) | 50 (36–80) | 0.007* | 45 (36–50) | 40 (35–50) | 0.516 |
| SpO2 (%) | 95 (92–98) | 95 (92–98) | 0.553 | 95 (91–98) | 95 (91–97) | 0.775 |
| SF ratio | 176 (97–243) | 208 (115–257) | 0.006* | 200 (170–257) | 238 (185–277) | 0.035* |
| ROX index | 5.93 (3.93–8.97) | 8.18 (5.00–11.55) | <0.001* | 7.92 (6.06–10.78) | 10.02 (7.23–13.04) | 0.021* |
| PaCO2 (mmHg) | 33 (29–40) | 34 (30–37) | 0.356 | 35 (31–39) | 35 (29–39) | 0.426 |
| Serum HCO3 (mmol/l) | 22.6 (20.0–26.4) | 22.5 (19.3–26.0) | 0.150 | 22.5 (19.2–26.6) | 23.0 (20.2–26.2) | 0.064 |
| pH | 7.44 (7.41–7.48) | 7.43 (7.39–7.48) | 0.208 | 7.43 (7.37–7.48) | 7.41 (7.38–7.46) | 0.617 |
| Heart rate (bpm) | 106 (89–118) | 95 (83–107) | <0.001* | 96 (83–113) | 100 (81–114) | 0.960 |
| Systolic blood pressure (mmHg) | 136 (115–157) | 128 (111–153) | 0.256 | 121 (101–141) | 126 (107–145) | 0.351 |
| Diastolic blood pressure (mmHg) | 75 (63–85) | 72 (61–83) | 0.661 | 66 (52–78) | 70 (60–81) | 0.072 |
| Median GCS | 15 (15–15) | 15 (15–15) | 0.175 | 15 (14–15) | 15 (15–15) | 0.436 |
| 1hr after HFNC administered | ||||||
| Respiratory rate (breaths/min) | 26 (23–31) | 23 (19–30) | 0.004* | 24 (19–28) | 22 (18–27) | 0.338 |
| Flow (L/min) | 50 (50–60) | 50 (40–50) | 0.605 | 50 (45–60) | 50 (40–60) | 0.783 |
| FiO2 (%) | 60 (50–70) | 50 (40–60) | <0.001* | 50 (40–60) | 40 (35–50) | 0.001* |
| SpO2 (%) | 96 (93–98) | 96 (94–99) | 0.436 | 95 (93–97) | 96 (94–98) | 0.877 |
| SF ratio | 164 (134–194) | 190 (158–232) | <0.001* | 196 (165–240) | 240 (186–271) | 0.001* |
| ROX index | 6.74 (4.53–8.70) | 8.56 (6.74–11.19) | <0.001* | 8.03 (6.58–11.06) | 10.35 (7.48–14.00) | 0.001* |
| PaCO2 (mmHg) | 33 (29–38) | 34 (29–38) | 0.823 | 34 (30–39) | 33 (28–38) | 0.814 |
| Serum HCO3 (mmol/l) | 23.1 (20.0–27.0) | 23.0 (20.7–26.0) | 0.223 | 23.8 (20.3–26.0) | 22.0 (20.0–24.5) | 0.259 |
| pH | 7.45 (7.40–7.49) | 7.44 (7.40–7.47) | 0.616 | 7.44 (7.40–7.50) | 7.44 (7.40–7.47) | 0.440 |
| Heart rate (bpm) | 102 (86–118) | 92 (82–103) | <0.001* | 98 (83–112) | 96 (81–106) | 0.289 |
| Systolic blood pressure (mmHg) | 133 (116–150) | 129 (111–149) | 0.727 | 119 (107–137) | 120 (106–137) | 0.916 |
| Diastolic blood pressure (mmHg) | 69 (61–81) | 69 (60–79) | 0.809 | 68 (55–77) | 67 (59–77) | 0.564 |
| Median GCS | 15 (15–15) | 15 (15–15) | 0.682 | 15 (14–15) | 15 (15–15) | 0.389 |
* represents those parameters that are statistically significant.