All | SOC | CPAP | HFNO | Statistically significant differences | |
Number of participants | 30 | 10 | 10 | 10 | – |
Male (n)
| 17 | 6 | 5 | 6 | – |
Mean age (95% CI) (min max) | 56(52 to 60) (35–75) | 54(47 to 61) (35–74) | 60(52 to 68) (44–75) | 53(45 to 61) (39–68) | p=NS (ANOVA) |
Ethnicity | |||||
Asian – Pakistani (n) | 10 | 2 | 6 | 2 | – |
White - British (n) | 8 | 4 | 0 | 4 | – |
Not given (n) | 4 | 1 | 3 | 0 | – |
Asian - Indian (n) | 3 | 0 | 0 | 3 | – |
Asian - other (n) | 2 | 1 | 0 | 1 | – |
White - other (n) | 1 | 1 | 0 | 0 | – |
Caribbean (n) | 1 | 1 | 0 | 0 | – |
Mixed – White and Caribbean (n) | 1 | 0 | 1 | 0 | – |
Mean number of days of illness at time of hospital admission (95% CI) (min–max) | 9(8 to 11) (0–17) | 8(5 to 11) (2–15) | 8(6 to 11)) (3–12) | 11(8 to 14) (0–15) | p=NS (ANOVA) |
Mean number of days of illness at time of sampling (95% CI) (min–max) | 12(10 to 14) (3–25) | 9(5 to 13) (3–18) | 13(9 to 16) (6–24) | 16(13 to 19) (11–25) | p=0.02 (ANOVA) SOC vs CPAP p=NS (unpaired t-test) SOC vs HFNO p<0.01 (unpaired t-test) |
Median number of days in hospital at the time of sampling (IQR) (min–max) | 2(1–5) (0–14) | 1 (0–2) (0–3) | 4.5(2–6) (1–9) | 3(2–6) (2–14) | p<0.01 (Kruskal-Wallis) SOC vs CPAP p<0.01 (Mann-Whitney) SOC vs HFNO p<0.01 (Mann-Whitney) |
Mean number of days CPAP/HFNO at time of sampling (95% CI) (min–max) | N/A | N/A | 2.4 [1.5–3.3] (1-4) | 1.8 [1.0–2.6] (0–3) | – |
Median FiO2 at time of sampling (IQR) (min-max) | 56(40 to 73) (35–98) | 59(40 to 65) (40–98) | 48(40 to 62) (40–80) | 63(40 to 91) (35–98) | p=NS (Kruskal-Wallis) |
Mean SpO2 at time of sampling (95% CI mean) (min–max) | 94(93 to 95) (92–99) | 95(93 to 96) (92–99) | 94(93 to 95) (92–96) | 94(93 to 96) (92–98) | p=NS (ANOVA) |
Room type | |||||
Open bay/cohort area | 12 | 4 | 4 | 4 | – |
Side room – ambient pressure | 8 | 5 | 0 | 3 | – |
Side room – negative pressure | 7 | 0 | 6 | 1 | – |
Side room – natural airflow | 3 | 1 | 0 | 2 | – |
Estimated air changes per hour | |||||
10 | 15 | 6 | 6 | 6 | – |
4–6 | 10 | 4 | 4 | 2 | – |
4 | 2 | 0 | 0 | 2 | – |
Mean room air temperature (°C) at time of sampling (95% CI) (min–max) | 21.9(21 to 23) (18.0–25.0) | 23.2(22 to 24) (20.0–25.0) | 21.9(21 to 23) (19.0–24.0) | 20.7(19 to 22) (18.0–23.0) | p=0.01 (ANOVA) SOC vs CPAP p=NS (unpaired t-test) SOC vs HFNO p<0.01 (unpaired t-test) |
Median room air CO2 content (ppm) at time of sampling (IQR) (min–max) | 574.5(500–808) (419–1548) | 672.5(530–774) (459–1548) | 502.0(448–582) (419-618) | 915.0 (459–1303) (506–1460) | p=0.01 (Kruskal-Wallis) SOC vs CPAP p=0.02 (Mann-Whitney) SOC vs HFNO p=NS (Mann-Whitney) |
Mean room air humidity (%) at time of sampling (95% CI mean) (min–max) | 37.6(34 to 41)(22.0–58.0) | 37.5(32 to 43)(23.0–41.0) | 30.4(26 to 35)(23.0–41.0) | 44.8(37 to 53)(26.0–58.0) | p<0.01 (ANOVA) SOC vs CPAP p=0.03 (unpaired t-test) SOC vs HFNO p=NS (unpaired t-test) |
Receiving humidified oxygen (n) | 15 | 6 | 2 | 7 | – |
CPAP full face mask (unvented) (n) | N/A | N/A | 8 | N/A | – |
CPAP partial face mask (vented) (n) | N/A | N/A | 2 | N/A | – |
A total of 30 participants with moderate/severe COVID-19 were enrolled into the study. Paired t-tests were post-hoc analysis of differences between SOC and CPAP/HFNO study groups only.
ANOVA, analysis of variance; CPAP, continuous positive airway pressure; FiO2, fraction of inspired oxygen; HFNO, high-flow nasal oxygen; N/A, not applicable; NS, not significant; SOC, supplemental oxygen care; SpO2, oxygen saturation.